Interface CachedRowSet
- All Superinterfaces:
AutoCloseable,Joinable,ResultSet,RowSet,Wrapper
- All Known Subinterfaces:
FilteredRowSet,JoinRowSet,WebRowSet
CachedRowSet must implement.
The reference implementation of the CachedRowSet interface provided
by Oracle Corporation is a standard implementation. Developers may use this implementation
just as it is, they may extend it, or they may choose to write their own implementations
of this interface.
A CachedRowSet object is a container for rows of data
that caches its rows in memory, which makes it possible to operate without always being
connected to its data source. Further, it is a
JavaBeans component and is scrollable,
updatable, and serializable. A CachedRowSet object typically
contains rows from a result set, but it can also contain rows from any file
with a tabular format, such as a spread sheet. The reference implementation
supports getting data only from a ResultSet object, but
developers can extend the SyncProvider implementations to provide
access to other tabular data sources.
An application can modify the data in a CachedRowSet object, and
those modifications can then be propagated back to the source of the data.
A CachedRowSet object is a disconnected rowset, which means
that it makes use of a connection to its data source only briefly. It connects to its
data source while it is reading data to populate itself with rows and again
while it is propagating changes back to its underlying data source. The rest
of the time, a CachedRowSet object is disconnected, including
while its data is being modified. Being disconnected makes a RowSet
object much leaner and therefore much easier to pass to another component. For
example, a disconnected RowSet object can be serialized and passed
over the wire to a thin client such as a personal digital assistant (PDA).
1.0 Creating a CachedRowSet Object
The following line of code uses the default constructor for
CachedRowSet
supplied in the reference implementation (RI) to create a default
CachedRowSet object.
CachedRowSetImpl crs = new CachedRowSetImpl();
This new CachedRowSet object will have its properties set to the
default properties of a BaseRowSet object, and, in addition, it will
have an RIOptimisticProvider object as its synchronization provider.
RIOptimisticProvider, one of two SyncProvider
implementations included in the RI, is the default provider that the
SyncFactory singleton will supply when no synchronization
provider is specified.
A SyncProvider object provides a CachedRowSet object
with a reader (a RowSetReader object) for reading data from a
data source to populate itself with data. A reader can be implemented to read
data from a ResultSet object or from a file with a tabular format.
A SyncProvider object also provides
a writer (a RowSetWriter object) for synchronizing any
modifications to the CachedRowSet object's data made while it was
disconnected with the data in the underlying data source.
A writer can be implemented to exercise various degrees of care in checking
for conflicts and in avoiding them.
(A conflict occurs when a value in the data source has been changed after
the rowset populated itself with that value.)
The RIOptimisticProvider implementation assumes there will be
few or no conflicts and therefore sets no locks. It updates the data source
with values from the CachedRowSet object only if there are no
conflicts.
Other writers can be implemented so that they always write modified data to
the data source, which can be accomplished either by not checking for conflicts
or, on the other end of the spectrum, by setting locks sufficient to prevent data
in the data source from being changed. Still other writer implementations can be
somewhere in between.
A CachedRowSet object may use any
SyncProvider implementation that has been registered
with the SyncFactory singleton. An application
can find out which SyncProvider implementations have been
registered by calling the following line of code.
java.util.Enumeration providers = SyncFactory.getRegisteredProviders();
There are two ways for a CachedRowSet object to specify which
SyncProvider object it will use.
- Supplying the name of the implementation to the constructor
The following line of code creates theCachedRowSetobject crs2 that is initialized with default values except that itsSyncProviderobject is the one specified.CachedRowSetImpl crs2 = new CachedRowSetImpl( "com.fred.providers.HighAvailabilityProvider"); - Setting the
SyncProviderusing theCachedRowSetmethodsetSyncProvider
The following line of code resets theSyncProviderobject for crs, theCachedRowSetobject created with the default constructor.crs.setSyncProvider("com.fred.providers.HighAvailabilityProvider");
SyncFactory and SyncProvider for
more details.
2.0 Retrieving Data from a CachedRowSet Object
Data is retrieved from a CachedRowSet object by using the
getter methods inherited from the ResultSet
interface. The following examples, in which crs is a
CachedRowSet
object, demonstrate how to iterate through the rows, retrieving the column
values in each row. The first example uses the version of the
getter methods that take a column number; the second example
uses the version that takes a column name. Column numbers are generally
used when the RowSet object's command
is of the form SELECT * FROM TABLENAME; column names are most
commonly used when the command specifies columns by name.
while (crs.next()) {
String name = crs.getString(1);
int id = crs.getInt(2);
Clob comment = crs.getClob(3);
short dept = crs.getShort(4);
System.out.println(name + " " + id + " " + comment + " " + dept);
}
while (crs.next()) {
String name = crs.getString("NAME");
int id = crs.getInt("ID");
Clob comment = crs.getClob("COM");
short dept = crs.getShort("DEPT");
System.out.println(name + " " + id + " " + comment + " " + dept);
}
2.1 Retrieving RowSetMetaData
An application can get information about the columns in a CachedRowSet
object by calling ResultSetMetaData and RowSetMetaData
methods on a RowSetMetaData object. The following code fragment,
in which crs is a CachedRowSet object, illustrates the process.
The first line creates a RowSetMetaData object with information
about the columns in crs. The method getMetaData,
inherited from the ResultSet interface, returns a
ResultSetMetaData object, which is cast to a
RowSetMetaData object before being assigned to the variable
rsmd. The second line finds out how many columns jrs has, and
the third line gets the JDBC type of values stored in the second column of
jrs.
RowSetMetaData rsmd = (RowSetMetaData)crs.getMetaData();
int count = rsmd.getColumnCount();
int type = rsmd.getColumnType(2);
The RowSetMetaData interface differs from the
ResultSetMetaData interface in two ways.
- It includes
settermethods: ARowSetobject uses these methods internally when it is populated with data from a differentResultSetobject. - It contains fewer
gettermethods: SomeResultSetMetaDatamethods to not apply to aRowSetobject. For example, methods retrieving whether a column value is writable or read only do not apply because all of aRowSetobject's columns will be writable or read only, depending on whether the rowset is updatable or not.
RowSetMetaData object, implementations must
override the getMetaData() method defined in
java.sql.ResultSet and return a RowSetMetaData object.
3.0 Updating a CachedRowSet Object
Updating a CachedRowSet object is similar to updating a
ResultSet object, but because the rowset is not connected to
its data source while it is being updated, it must take an additional step
to effect changes in its underlying data source. After calling the method
updateRow or insertRow, a
CachedRowSet
object must also call the method acceptChanges to have updates
written to the data source. The following example, in which the cursor is
on a row in the CachedRowSet object crs, shows
the code required to update two column values in the current row and also
update the RowSet object's underlying data source.
crs.updateShort(3, 58);
crs.updateInt(4, 150000);
crs.updateRow();
crs.acceptChanges();
The next example demonstrates moving to the insert row, building a new
row on the insert row, inserting it into the rowset, and then calling the
method acceptChanges to add the new row to the underlying data
source. Note that as with the getter methods, the updater methods may take
either a column index or a column name to designate the column being acted upon.
crs.moveToInsertRow();
crs.updateString("Name", "Shakespeare");
crs.updateInt("ID", 10098347);
crs.updateShort("Age", 58);
crs.updateInt("Sal", 150000);
crs.insertRow();
crs.moveToCurrentRow();
crs.acceptChanges();
NOTE: Where the insertRow() method inserts the contents of a
CachedRowSet object's insert row is implementation-defined.
The reference implementation for the CachedRowSet interface
inserts a new row immediately following the current row, but it could be
implemented to insert new rows in any number of other places.
Another thing to note about these examples is how they use the method
acceptChanges. It is this method that propagates changes in
a CachedRowSet object back to the underlying data source,
calling on the RowSet object's writer internally to write
changes to the data source. To do this, the writer has to incur the expense
of establishing a connection with that data source. The
preceding two code fragments call the method acceptChanges
immediately after calling updateRow or insertRow.
However, when there are multiple rows being changed, it is more efficient to call
acceptChanges after all calls to updateRow
and insertRow have been made. If acceptChanges
is called only once, only one connection needs to be established.
4.0 Updating the Underlying Data Source
When the methodacceptChanges is executed, the
CachedRowSet object's writer, a RowSetWriterImpl
object, is called behind the scenes to write the changes made to the
rowset to the underlying data source. The writer is implemented to make a
connection to the data source and write updates to it.
A writer is made available through an implementation of the
SyncProvider interface, as discussed in section 1,
"Creating a CachedRowSet Object."
The default reference implementation provider, RIOptimisticProvider,
has its writer implemented to use an optimistic concurrency control
mechanism. That is, it maintains no locks in the underlying database while
the rowset is disconnected from the database and simply checks to see if there
are any conflicts before writing data to the data source. If there are any
conflicts, it does not write anything to the data source.
The reader/writer facility
provided by the SyncProvider class is pluggable, allowing for the
customization of data retrieval and updating. If a different concurrency
control mechanism is desired, a different implementation of
SyncProvider can be plugged in using the method
setSyncProvider.
In order to use the optimistic concurrency control routine, the
RIOptimisticProvider maintains both its current
value and its original value (the value it had immediately preceding the
current value). Note that if no changes have been made to the data in a
RowSet object, its current values and its original values are the same,
both being the values with which the RowSet object was initially
populated. However, once any values in the RowSet object have been
changed, the current values and the original values will be different, though at
this stage, the original values are still the initial values. With any subsequent
changes to data in a RowSet object, its original values and current
values will still differ, but its original values will be the values that
were previously the current values.
Keeping track of original values allows the writer to compare the RowSet
object's original value with the value in the database. If the values in
the database differ from the RowSet object's original values, which means that
the values in the database have been changed, there is a conflict.
Whether a writer checks for conflicts, what degree of checking it does, and how
it handles conflicts all depend on how it is implemented.
5.0 Registering and Notifying Listeners
Being JavaBeans components, all rowsets participate in the JavaBeans event model, inheriting methods for registering listeners and notifying them of changes from theBaseRowSet class. A listener for a
CachedRowSet object is a component that wants to be notified
whenever there is a change in the rowset. For example, if a
CachedRowSet object contains the results of a query and
those
results are being displayed in, say, a table and a bar graph, the table and
bar graph could be registered as listeners with the rowset so that they can
update themselves to reflect changes. To become listeners, the table and
bar graph classes must implement the RowSetListener interface.
Then they can be added to the CachedRowSet object's list of
listeners, as is illustrated in the following lines of code.
crs.addRowSetListener(table);
crs.addRowSetListener(barGraph);
Each CachedRowSet method that moves the cursor or changes
data also notifies registered listeners of the changes, so
table and barGraph will be notified when there is
a change in crs.
6.0 Passing Data to Thin Clients
One of the main reasons to use aCachedRowSet object is to
pass data between different components of an application. Because it is
serializable, a CachedRowSet object can be used, for example,
to send the result of a query executed by an enterprise JavaBeans component
running in a server environment over a network to a client running in a
web browser.
While a CachedRowSet object is disconnected, it can be much
leaner than a ResultSet object with the same data.
As a result, it can be especially suitable for sending data to a thin client
such as a PDA, where it would be inappropriate to use a JDBC driver
due to resource limitations or security considerations.
Thus, a CachedRowSet object provides a means to "get rows in"
without the need to implement the full JDBC API.
7.0 Scrolling and Updating
A second major use forCachedRowSet objects is to provide
scrolling and updating for ResultSet objects that
do not provide these capabilities themselves. In other words, a
CachedRowSet object can be used to augment the
capabilities of a JDBC technology-enabled driver (hereafter called a
"JDBC driver") when the DBMS does not provide full support for scrolling and
updating. To achieve the effect of making a non-scrollable and read-only
ResultSet object scrollable and updatable, a programmer
simply needs to create a CachedRowSet object populated
with that ResultSet object's data. This is demonstrated
in the following code fragment, where stmt is a
Statement object.
ResultSet rs = stmt.executeQuery("SELECT * FROM EMPLOYEES");
CachedRowSetImpl crs = new CachedRowSetImpl();
crs.populate(rs);
The object crs now contains the data from the table
EMPLOYEES, just as the object rs does.
The difference is that the cursor for crs can be moved
forward, backward, or to a particular row even if the cursor for
rs can move only forward. In addition, crs is
updatable even if rs is not because by default, a
CachedRowSet object is both scrollable and updatable.
In summary, a CachedRowSet object can be thought of as simply
a disconnected set of rows that are being cached outside of a data source.
Being thin and serializable, it can easily be sent across a wire,
and it is well suited to sending data to a thin client. However, a
CachedRowSet object does have a limitation: It is limited in
size by the amount of data it can store in memory at one time.
8.0 Getting Universal Data Access
Another advantage of theCachedRowSet class is that it makes it
possible to retrieve and store data from sources other than a relational
database. The reader for a rowset can be implemented to read and populate
its rowset with data from any tabular data source, including a spreadsheet
or flat file.
Because both a CachedRowSet object and its metadata can be
created from scratch, a component that acts as a factory for rowsets
can use this capability to create a rowset containing data from
non-SQL data sources. Nevertheless, it is expected that most of the time,
CachedRowSet objects will contain data that was fetched
from an SQL database using the JDBC API.
9.0 Setting Properties
All rowsets maintain a set of properties, which will usually be set using a tool. The number and kinds of properties a rowset has will vary, depending on what the rowset does and how it gets its data. For example, rowsets that get their data from aResultSet object need to
set the properties that are required for making a database connection.
If a rowset uses the DriverManager facility to make a
connection, it needs to set a property for the JDBC URL that identifies
the appropriate driver, and it needs to set the properties that give the
user name and password.
If, on the other hand, the rowset uses a DataSource object
to make the connection, which is the preferred method, it does not need to
set the property for the JDBC URL. Instead, it needs to set
properties for the logical name of the data source, for the user name,
and for the password.
NOTE: In order to use a DataSource object for making a
connection, the DataSource object must have been registered
with a naming service that uses the Java Naming and Directory
Interface (JNDI) API. This registration
is usually done by a person acting in the capacity of a system
administrator.
In order to be able to populate itself with data from a database, a rowset
needs to set a command property. This property is a query that is a
PreparedStatement object, which allows the query to have
parameter placeholders that are set at run time, as opposed to design time.
To set these placeholder parameters with values, a rowset provides
setter methods for setting values of each data type,
similar to the setter methods provided by the PreparedStatement
interface.
The following code fragment illustrates how the CachedRowSet
object crs might have its command property set. Note that if a
tool is used to set properties, this is the code that the tool would use.
crs.setCommand("SELECT FIRST_NAME, LAST_NAME, ADDRESS FROM CUSTOMERS " +
"WHERE CREDIT_LIMIT > ? AND REGION = ?");
The values that will be used to set the command's placeholder parameters are
contained in the RowSet object's params field, which is a
Vector object.
The CachedRowSet class provides a set of setter
methods for setting the elements in its params field. The
following code fragment demonstrates setting the two parameters in the
query from the previous example.
crs.setInt(1, 5000);
crs.setString(2, "West");
The params field now contains two elements, each of which is
an array two elements long. The first element is the parameter number;
the second is the value to be set.
In this case, the first element of params is
1, 5000, and the second element is 2,
"West". When an application calls the method
execute, it will in turn call on this RowSet object's reader,
which will in turn invoke its readData method. As part of
its implementation, readData will get the values in
params and use them to set the command's placeholder
parameters.
The following code fragment gives an idea of how the reader
does this, after obtaining the Connection object
con.
PreparedStatement pstmt = con.prepareStatement(crs.getCommand());
reader.decodeParams();
// decodeParams figures out which setter methods to use and does something
// like the following:
// for (i = 0; i < params.length; i++) {
// pstmt.setObject(i + 1, params[i]);
// }
At this point, the command for crs is the query "SELECT
FIRST_NAME, LAST_NAME, ADDRESS FROM CUSTOMERS WHERE CREDIT_LIMIT > 5000
AND REGION = "West". After the readData method executes
this command with the following line of code, it will have the data from
rs with which to populate crs.
ResultSet rs = pstmt.executeQuery();
The preceding code fragments give an idea of what goes on behind the
scenes; they would not appear in an application, which would not invoke
methods like readData and decodeParams.
In contrast, the following code fragment shows what an application might do.
It sets the rowset's command, sets the command's parameters, and executes
the command. Simply by calling the execute method,
crs populates itself with the requested data from the
table CUSTOMERS.
crs.setCommand("SELECT FIRST_NAME, LAST_NAME, ADDRESS FROM CUSTOMERS" +
"WHERE CREDIT_LIMIT > ? AND REGION = ?");
crs.setInt(1, 5000);
crs.setString(2, "West");
crs.execute();
10.0 Paging Data
Because aCachedRowSet object stores data in memory,
the amount of data that it can contain at any one
time is determined by the amount of memory available. To get around this limitation,
a CachedRowSet object can retrieve data from a ResultSet
object in chunks of data, called pages. To take advantage of this mechanism,
an application sets the number of rows to be included in a page using the method
setPageSize. In other words, if the page size is set to five, a chunk
of five rows of
data will be fetched from the data source at one time. An application can also
optionally set the maximum number of rows that may be fetched at one time. If the
maximum number of rows is set to zero, or no maximum number of rows is set, there is
no limit to the number of rows that may be fetched at a time.
After properties have been set,
the CachedRowSet object must be populated with data
using either the method populate or the method execute.
The following lines of code demonstrate using the method populate.
Note that this version of the method takes two parameters, a ResultSet
handle and the row in the ResultSet object from which to start
retrieving rows.
CachedRowSet crs = new CachedRowSetImpl();
crs.setMaxRows(20);
crs.setPageSize(4);
crs.populate(rsHandle, 10);
When this code runs, crs will be populated with four rows from
rsHandle starting with the tenth row.
The next code fragment shows populating a CachedRowSet object using the
method execute, which may or may not take a Connection
object as a parameter. This code passes execute the Connection
object conHandle.
Note that there are two differences between the following code
fragment and the previous one. First, the method setMaxRows is not
called, so there is no limit set for the number of rows that crs may contain.
(Remember that crs always has the overriding limit of how much data it can
store in memory.) The second difference is that the you cannot pass the method
execute the number of the row in the ResultSet object
from which to start retrieving rows. This method always starts with the first row.
CachedRowSet crs = new CachedRowSetImpl();
crs.setPageSize(5);
crs.execute(conHandle);
After this code has run, crs will contain five rows of data from the
ResultSet object produced by the command for crs. The writer
for crs will use conHandle to connect to the data source and
execute the command for crs. An application is then able to operate on the
data in crs in the same way that it would operate on data in any other
CachedRowSet object.
To access the next page (chunk of data), an application calls the method
nextPage. This method creates a new CachedRowSet object
and fills it with the next page of data. For example, assume that the
CachedRowSet object's command returns a ResultSet object
rs with 1000 rows of data. If the page size has been set to 100, the first
call to the method nextPage will create a CachedRowSet object
containing the first 100 rows of rs. After doing what it needs to do with the
data in these first 100 rows, the application can again call the method
nextPage to create another CachedRowSet object
with the second 100 rows from rs. The data from the first CachedRowSet
object will no longer be in memory because it is replaced with the data from the
second CachedRowSet object. After the tenth call to the method nextPage,
the tenth CachedRowSet object will contain the last 100 rows of data from
rs, which are stored in memory. At any given time, the data from only one
CachedRowSet object is stored in memory.
The method nextPage returns true as long as the current
page is not the last page of rows and false when there are no more pages.
It can therefore be used in a while loop to retrieve all of the pages,
as is demonstrated in the following lines of code.
CachedRowSet crs = CachedRowSetImpl();
crs.setPageSize(100);
crs.execute(conHandle);
while(crs.nextPage()) {
while(crs.next()) {
. . . // operate on chunks (of 100 rows each) in crs,
// row by row
}
}
After this code fragment has been run, the application will have traversed all
1000 rows, but it will have had no more than 100 rows in memory at a time.
The CachedRowSet interface also defines the method previousPage.
Just as the method nextPage is analogous to the ResultSet
method next, the method previousPage is analogous to
the ResultSet method previous. Similar to the method
nextPage, previousPage creates a CachedRowSet
object containing the number of rows set as the page size. So, for instance, the
method previousPage could be used in a while loop at
the end of the preceding code fragment to navigate back through the pages from the last
page to the first page.
The method previousPage is also similar to nextPage
in that it can be used in a while
loop, except that it returns true as long as there is another page
preceding it and false when there are no more pages ahead of it.
By positioning the cursor after the last row for each page,
as is done in the following code fragment, the method previous
navigates from the last row to the first row in each page.
The code could also have left the cursor before the first row on each page and then
used the method next in a while loop to navigate each page
from the first row to the last row.
The following code fragment assumes a continuation from the previous code fragment,
meaning that the cursor for the tenth CachedRowSet object is on the
last row. The code moves the cursor to after the last row so that the first
call to the method previous will put the cursor back on the last row.
After going through all of the rows in the last page (the CachedRowSet
object crs), the code then enters
the while loop to get to the ninth page, go through the rows backwards,
go to the eighth page, go through the rows backwards, and so on to the first row
of the first page.
crs.afterLast();
while(crs.previous()) {
. . . // navigate through the rows, last to first
{
while(crs.previousPage()) {
crs.afterLast();
while(crs.previous()) {
. . . // go from the last row to the first row of each page
}
}
- Since:
- 1.5
-
Field Summary
FieldsModifier and TypeFieldDescriptionstatic final booleanDeprecated.Because this field is final (it is part of an interface), its value cannot be changed.Fields declared in interface java.sql.ResultSet
CLOSE_CURSORS_AT_COMMIT, CONCUR_READ_ONLY, CONCUR_UPDATABLE, FETCH_FORWARD, FETCH_REVERSE, FETCH_UNKNOWN, HOLD_CURSORS_OVER_COMMIT, TYPE_FORWARD_ONLY, TYPE_SCROLL_INSENSITIVE, TYPE_SCROLL_SENSITIVE -
Method Summary
Modifier and TypeMethodDescriptionvoidPropagates row update, insert and delete changes made to thisCachedRowSetobject to the underlying data source.voidacceptChanges(Connection con) Propagates all row update, insert and delete changes to the data source backing thisCachedRowSetobject using the specifiedConnectionobject to establish a connection to the data source.booleancolumnUpdated(int idx) Indicates whether the designated column in the current row of thisCachedRowSetobject has been updated.booleancolumnUpdated(String columnName) Indicates whether the designated column in the current row of thisCachedRowSetobject has been updated.voidcommit()EachCachedRowSetobject'sSyncProvidercontains aConnectionobject from theResultSetor JDBC properties passed to it's constructors.Creates aRowSetobject that is a deep copy of the data in thisCachedRowSetobject.Creates aCachedRowSetobject that is a deep copy of thisCachedRowSetobject's data but is independent of it.Creates aCachedRowSetobject that is an empty copy of thisCachedRowSetobject.Returns a newRowSetobject backed by the same data as that of thisCachedRowSetobject.voidexecute(Connection conn) Populates thisCachedRowSetobject with data, using the given connection to produce the result set from which the data will be read.int[]Returns an array containing one or more column numbers indicating the columns that form a key that uniquely identifies a row in thisCachedRowSetobject.Returns aResultSetobject containing the original value of thisCachedRowSetobject.Returns aResultSetobject containing the original value for the current row only of thisCachedRowSetobject.intReturns the page-size for theCachedRowSetobjectRetrieves the first warning reported by calls on thisRowSetobject.booleanRetrieves abooleanindicating whether rows marked for deletion appear in the set of current rows.Retrieves theSyncProviderimplementation for thisCachedRowSetobject.Returns an identifier for the object (table) that was used to create thisCachedRowSetobject.booleannextPage()Increments the current page of theCachedRowSet.voidPopulates thisCachedRowSetobject with data from the givenResultSetobject.voidPopulates thisCachedRowSetobject with data from the givenResultSetobject.booleanDecrements the current page of theCachedRowSet.voidrelease()Releases the current contents of thisCachedRowSetobject and sends arowSetChangedevent to all registered listeners.voidRestores thisCachedRowSetobject to its original value, that is, its value before the last set of changes.voidrollback()EachCachedRowSetobject'sSyncProvidercontains aConnectionobject from the originalResultSetor JDBC properties passed to it.voidEachCachedRowSetobject'sSyncProvidercontains aConnectionobject from the originalResultSetor JDBC properties passed to it.voidrowSetPopulated(RowSetEvent event, int numRows) Notifies registered listeners that a RowSet object in the given RowSetEvent object has populated a number of additional rows.voidsetKeyColumns(int[] keys) Sets thisCachedRowSetobject'skeyColsfield with the given array of column numbers, which forms a key for uniquely identifying a row in thisCachedRowSetobject.voidSets the metadata for thisCachedRowSetobject with the givenRowSetMetaDataobject.voidSets the current row in thisCachedRowSetobject as the original row.voidsetPageSize(int size) Sets theCachedRowSetobject's page-size.voidsetShowDeleted(boolean b) Sets the propertyshowDeletedto the givenbooleanvalue, which determines whether rows marked for deletion appear in the set of current rows.voidsetSyncProvider(String provider) Sets theSyncProviderobject for thisCachedRowSetobject to the one specified.voidsetTableName(String tabName) Sets the identifier for the table from which thisCachedRowSetobject was derived to the given table name.intsize()Returns the number of rows in thisCachedRowSetobject.Collection<?> Converts thisCachedRowSetobject to aCollectionobject that contains all of thisCachedRowSetobject's data.Collection<?> toCollection(int column) Converts the designated column in thisCachedRowSetobject to aCollectionobject.Collection<?> toCollection(String column) Converts the designated column in thisCachedRowSetobject to aCollectionobject.voidCancels the deletion of the current row and notifies listeners that a row has changed.voidImmediately removes the current row from thisCachedRowSetobject if the row has been inserted, and also notifies listeners that a row has changed.voidImmediately reverses the last update operation if the row has been modified.Methods declared in interface javax.sql.rowset.Joinable
getMatchColumnIndexes, getMatchColumnNames, setMatchColumn, setMatchColumn, setMatchColumn, setMatchColumn, unsetMatchColumn, unsetMatchColumn, unsetMatchColumn, unsetMatchColumnMethods declared in interface java.sql.ResultSet
absolute, afterLast, beforeFirst, cancelRowUpdates, clearWarnings, close, deleteRow, findColumn, first, getArray, getArray, getAsciiStream, getAsciiStream, getBigDecimal, getBigDecimal, getBigDecimal, getBigDecimal, getBinaryStream, getBinaryStream, getBlob, getBlob, getBoolean, getBoolean, getByte, getByte, getBytes, getBytes, getCharacterStream, getCharacterStream, getClob, getClob, getConcurrency, getCursorName, getDate, getDate, getDate, getDate, getDouble, getDouble, getFetchDirection, getFetchSize, getFloat, getFloat, getHoldability, getInt, getInt, getLong, getLong, getMetaData, getNCharacterStream, getNCharacterStream, getNClob, getNClob, getNString, getNString, getObject, getObject, getObject, getObject, getObject, getObject, getRef, getRef, getRow, getRowId, getRowId, getShort, getShort, getSQLXML, getSQLXML, getStatement, getString, getString, getTime, getTime, getTime, getTime, getTimestamp, getTimestamp, getTimestamp, getTimestamp, getType, getUnicodeStream, getUnicodeStream, getURL, getURL, getWarnings, insertRow, isAfterLast, isBeforeFirst, isClosed, isFirst, isLast, last, moveToCurrentRow, moveToInsertRow, next, previous, refreshRow, relative, rowDeleted, rowInserted, rowUpdated, setFetchDirection, setFetchSize, updateArray, updateArray, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateAsciiStream, updateBigDecimal, updateBigDecimal, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBinaryStream, updateBlob, updateBlob, updateBlob, updateBlob, updateBlob, updateBlob, updateBoolean, updateBoolean, updateByte, updateByte, updateBytes, updateBytes, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateCharacterStream, updateClob, updateClob, updateClob, updateClob, updateClob, updateClob, updateDate, updateDate, updateDouble, updateDouble, updateFloat, updateFloat, updateInt, updateInt, updateLong, updateLong, updateNCharacterStream, updateNCharacterStream, updateNCharacterStream, updateNCharacterStream, updateNClob, updateNClob, updateNClob, updateNClob, updateNClob, updateNClob, updateNString, updateNString, updateNull, updateNull, updateObject, updateObject, updateObject, updateObject, updateObject, updateObject, updateObject, updateObject, updateRef, updateRef, updateRow, updateRowId, updateRowId, updateShort, updateShort, updateSQLXML, updateSQLXML, updateString, updateString, updateTime, updateTime, updateTimestamp, updateTimestamp, wasNullMethods declared in interface javax.sql.RowSet
addRowSetListener, clearParameters, execute, getCommand, getDataSourceName, getEscapeProcessing, getMaxFieldSize, getMaxRows, getPassword, getQueryTimeout, getTransactionIsolation, getTypeMap, getUrl, getUsername, isReadOnly, removeRowSetListener, setArray, setAsciiStream, setAsciiStream, setAsciiStream, setAsciiStream, setBigDecimal, setBigDecimal, setBinaryStream, setBinaryStream, setBinaryStream, setBinaryStream, setBlob, setBlob, setBlob, setBlob, setBlob, setBlob, setBoolean, setBoolean, setByte, setByte, setBytes, setBytes, setCharacterStream, setCharacterStream, setCharacterStream, setCharacterStream, setClob, setClob, setClob, setClob, setClob, setClob, setCommand, setConcurrency, setDataSourceName, setDate, setDate, setDate, setDate, setDouble, setDouble, setEscapeProcessing, setFloat, setFloat, setInt, setInt, setLong, setLong, setMaxFieldSize, setMaxRows, setNCharacterStream, setNCharacterStream, setNCharacterStream, setNCharacterStream, setNClob, setNClob, setNClob, setNClob, setNClob, setNClob, setNString, setNString, setNull, setNull, setNull, setNull, setObject, setObject, setObject, setObject, setObject, setObject, setPassword, setQueryTimeout, setReadOnly, setRef, setRowId, setRowId, setShort, setShort, setSQLXML, setSQLXML, setString, setString, setTime, setTime, setTime, setTime, setTimestamp, setTimestamp, setTimestamp, setTimestamp, setTransactionIsolation, setType, setTypeMap, setUrl, setURL, setUsernameMethods declared in interface java.sql.Wrapper
isWrapperFor, unwrap
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Field Details
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COMMIT_ON_ACCEPT_CHANGES
Deprecated.Because this field is final (it is part of an interface), its value cannot be changed.Causes theCachedRowSetobject'sSyncProviderto commit the changes whenacceptChanges()is called. If set to false, the changes will not be committed until one of theCachedRowSetinterface transaction methods is called.- See Also:
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Method Details
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populate
Populates thisCachedRowSetobject with data from the givenResultSetobject.This method can be used as an alternative to the
executemethod when an application has a connection to an openResultSetobject. Using the methodpopulatecan be more efficient than using the version of theexecutemethod that takes no parameters because it does not open a new connection and re-execute thisCachedRowSetobject's command. Using thepopulatemethod is more a matter of convenience when compared to using the version ofexecutethat takes aResultSetobject.- Parameters:
data- theResultSetobject containing the data to be read into thisCachedRowSetobject- Throws:
SQLException- if a nullResultSetobject is supplied or thisCachedRowSetobject cannot retrieve the associatedResultSetMetaDataobject- See Also:
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execute
Populates thisCachedRowSetobject with data, using the given connection to produce the result set from which the data will be read. This method should close any database connections that it creates to ensure that thisCachedRowSetobject is disconnected except when it is reading data from its data source or writing data to its data source.The reader for this
CachedRowSetobject will use conn to establish a connection to the data source so that it can execute the rowset's command and read data from the the resultingResultSetobject into thisCachedRowSetobject. This method also closes conn after it has populated thisCachedRowSetobject.If this method is called when an implementation has already been populated, the contents and the metadata are (re)set. Also, if this method is called before the method
acceptChangeshas been called to commit outstanding updates, those updates are lost.- Parameters:
conn- a standard JDBCConnectionobject with valid properties- Throws:
SQLException- if an invalidConnectionobject is supplied or an error occurs in establishing the connection to the data source- See Also:
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acceptChanges
Propagates row update, insert and delete changes made to thisCachedRowSetobject to the underlying data source.This method calls on this
CachedRowSetobject's writer to do the work behind the scenes. StandardCachedRowSetimplementations should use theSyncFactorysingleton to obtain aSyncProviderinstance providing aRowSetWriterobject (writer). The writer will attempt to propagate changes made in thisCachedRowSetobject back to the data source.When the method
acceptChangesexecutes successfully, in addition to writing changes to the data source, it makes the values in the current row be the values in the original row.Depending on the synchronization level of the
SyncProviderimplementation being used, the writer will compare the original values with those in the data source to check for conflicts. When there is a conflict, theRIOptimisticProviderimplementation, for example, throws aSyncProviderExceptionand does not write anything to the data source.An application may choose to catch the
SyncProviderExceptionobject and retrieve theSyncResolverobject it contains. TheSyncResolverobject lists the conflicts row by row and sets a lock on the data source to avoid further conflicts while the current conflicts are being resolved. Further, for each conflict, it provides methods for examining the conflict and setting the value that should be persisted in the data source. After all conflicts have been resolved, an application must call theacceptChangesmethod again to write resolved values to the data source. If all of the values in the data source are already the values to be persisted, the methodacceptChangesdoes nothing.Some provider implementations may use locks to ensure that there are no conflicts. In such cases, it is guaranteed that the writer will succeed in writing changes to the data source when the method
acceptChangesis called. This method may be called immediately after the methodsupdateRow,insertRow, ordeleteRowhave been called, but it is more efficient to call it only once after all changes have been made so that only one connection needs to be established.Note: The
acceptChanges()method will determine if theCOMMIT_ON_ACCEPT_CHANGESis set to true or not. If it is set to true, all updates in the synchronization are committed to the data source. Otherwise, the application must explicitly call thecommit()orrollback()methods as appropriate.- Throws:
SyncProviderException- if the underlying synchronization provider's writer fails to write the updates back to the data source- See Also:
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acceptChanges
Propagates all row update, insert and delete changes to the data source backing thisCachedRowSetobject using the specifiedConnectionobject to establish a connection to the data source.The other version of the
acceptChangesmethod is not passed a connection because it uses theConnectionobject already defined within theRowSetobject, which is the connection used for populating it initially.This form of the method
acceptChangesis similar to the form that takes no arguments; however, unlike the other form, this form can be used only when the underlying data source is a JDBC data source. The updatedConnectionproperties must be used by theSyncProviderto reset theRowSetWriterconfiguration to ensure that the contents of theCachedRowSetobject are synchronized correctly.When the method
acceptChangesexecutes successfully, in addition to writing changes to the data source, it makes the values in the current row be the values in the original row.Depending on the synchronization level of the
SyncProviderimplementation being used, the writer will compare the original values with those in the data source to check for conflicts. When there is a conflict, theRIOptimisticProviderimplementation, for example, throws aSyncProviderExceptionand does not write anything to the data source.An application may choose to catch the
SyncProviderExceptionobject and retrieve theSyncResolverobject it contains. TheSyncResolverobject lists the conflicts row by row and sets a lock on the data source to avoid further conflicts while the current conflicts are being resolved. Further, for each conflict, it provides methods for examining the conflict and setting the value that should be persisted in the data source. After all conflicts have been resolved, an application must call theacceptChangesmethod again to write resolved values to the data source. If all of the values in the data source are already the values to be persisted, the methodacceptChangesdoes nothing.Some provider implementations may use locks to ensure that there are no conflicts. In such cases, it is guaranteed that the writer will succeed in writing changes to the data source when the method
acceptChangesis called. This method may be called immediately after the methodsupdateRow,insertRow, ordeleteRowhave been called, but it is more efficient to call it only once after all changes have been made so that only one connection needs to be established.Note: The
acceptChanges()method will determine if theCOMMIT_ON_ACCEPT_CHANGESis set to true or not. If it is set to true, all updates in the synchronization are committed to the data source. Otherwise, the application must explicitly call thecommitorrollbackmethods as appropriate.- Parameters:
con- a standard JDBCConnectionobject- Throws:
SyncProviderException- if the underlying synchronization provider's writer fails to write the updates back to the data source- See Also:
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restoreOriginal
Restores thisCachedRowSetobject to its original value, that is, its value before the last set of changes. If there have been no changes to the rowset or only one set of changes, the original value is the value with which thisCachedRowSetobject was populated; otherwise, the original value is the value it had immediately before its current value.When this method is called, a
CachedRowSetimplementation must ensure that all updates, inserts, and deletes to the current rowset instance are replaced by the previous values. In addition, the cursor should be reset to the first row and arowSetChangedevent should be fired to notify all registered listeners.- Throws:
SQLException- if an error occurs rolling back the current value of thisCachedRowSetobject to its previous value- See Also:
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release
Releases the current contents of thisCachedRowSetobject and sends arowSetChangedevent to all registered listeners. Any outstanding updates are discarded and the rowset contains no rows after this method is called. There are no interactions with the underlying data source, and any rowset content, metadata, and content updates should be non-recoverable.This
CachedRowSetobject should lock until its contents and associated updates are fully cleared, thus preventing 'dirty' reads by other components that hold a reference to thisRowSetobject. In addition, the contents cannot be released until all components reading thisCachedRowSetobject have completed their reads. ThisCachedRowSetobject should be returned to normal behavior after firing therowSetChangedevent.The metadata, including JDBC properties and Synchronization SPI properties, are maintained for future use. It is important that properties such as the
commandproperty be relevant to the originating data source from which thisCachedRowSetobject was originally established.This method empties a rowset, as opposed to the
closemethod, which marks the entire rowset as recoverable to allow the garbage collector the rowset's Java VM resources.- Throws:
SQLException- if an error occurs flushing the contents of thisCachedRowSetobject- See Also:
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undoDelete
Cancels the deletion of the current row and notifies listeners that a row has changed. After this method is called, the current row is no longer marked for deletion. This method can be called at any time during the lifetime of the rowset.In addition, multiple cancellations of row deletions can be made by adjusting the position of the cursor using any of the cursor position control methods such as:
CachedRowSet.absoluteCachedRowSet.firstCachedRowSet.last
- Throws:
SQLException- if (1) the current row has not been deleted or (2) the cursor is on the insert row, before the first row, or after the last row- See Also:
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undoInsert
Immediately removes the current row from thisCachedRowSetobject if the row has been inserted, and also notifies listeners that a row has changed. This method can be called at any time during the lifetime of a rowset and assuming the current row is within the exception limitations (see below), it cancels the row insertion of the current row.In addition, multiple cancellations of row insertions can be made by adjusting the position of the cursor using any of the cursor position control methods such as:
CachedRowSet.absoluteCachedRowSet.firstCachedRowSet.last
- Throws:
SQLException- if (1) the current row has not been inserted or (2) the cursor is before the first row, after the last row, or on the insert row- See Also:
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undoUpdate
Immediately reverses the last update operation if the row has been modified. This method can be called to reverse updates on all columns until all updates in a row have been rolled back to their state just prior to the last synchronization (acceptChanges) or population. This method may also be called while performing updates to the insert row.undoUpdatemay be called at any time during the lifetime of a rowset; however, after a synchronization has occurred, this method has no effect until further modification to the rowset data has occurred.- Throws:
SQLException- if the cursor is before the first row or after the last row in thisCachedRowSetobject- See Also:
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columnUpdated
Indicates whether the designated column in the current row of thisCachedRowSetobject has been updated.- Parameters:
idx- anintidentifying the column to be checked for updates- Returns:
trueif the designated column has been visibly updated;falseotherwise- Throws:
SQLException- if the cursor is on the insert row, before the first row, or after the last row- See Also:
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columnUpdated
Indicates whether the designated column in the current row of thisCachedRowSetobject has been updated.- Parameters:
columnName- aStringobject giving the name of the column to be checked for updates- Returns:
trueif the column has been visibly updated;falseotherwise- Throws:
SQLException- if the cursor is on the insert row, before the first row, or after the last row- See Also:
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toCollection
Converts thisCachedRowSetobject to aCollectionobject that contains all of thisCachedRowSetobject's data. Implementations have some latitude in how they can represent thisCollectionobject because of the abstract nature of theCollectionframework. Each row must be fully represented in either a general purposeCollectionimplementation or a specializedCollectionimplementation, such as aTreeMapobject or aVectorobject. An SQLNULLcolumn value must be represented as anullin the Java programming language.The standard reference implementation for the
CachedRowSetinterface uses aTreeMapobject for the rowset, with the values in each row being contained inVectorobjects. It is expected that most implementations will do the same.The
TreeMaptype of collection guarantees that the map will be in ascending key order, sorted according to the natural order for the key's class. Each key references aVectorobject that corresponds to one row of aRowSetobject. Therefore, the size of eachVectorobject must be exactly equal to the number of columns in theRowSetobject. The key used by theTreeMapcollection is determined by the implementation, which may choose to leverage a set key that is available within the internalRowSettabular structure by virtue of a key already set either on theRowSetobject itself or on the underlying SQL data.- Returns:
- a
Collectionobject that contains the values in each row in thisCachedRowSetobject - Throws:
SQLException- if an error occurs generating the collection- See Also:
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toCollection
Converts the designated column in thisCachedRowSetobject to aCollectionobject. Implementations have some latitude in how they can represent thisCollectionobject because of the abstract nature of theCollectionframework. Each column value should be fully represented in either a general purposeCollectionimplementation or a specializedCollectionimplementation, such as aVectorobject. An SQLNULLcolumn value must be represented as anullin the Java programming language.The standard reference implementation uses a
Vectorobject to contain the column values, and it is expected that most implementations will do the same. If aVectorobject is used, it size must be exactly equal to the number of rows in thisCachedRowSetobject.- Parameters:
column- anintindicating the column whose values are to be represented in aCollectionobject- Returns:
- a
Collectionobject that contains the values stored in the specified column of thisCachedRowSetobject - Throws:
SQLException- if an error occurs generating the collection or an invalid column id is provided- See Also:
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toCollection
Converts the designated column in thisCachedRowSetobject to aCollectionobject. Implementations have some latitude in how they can represent thisCollectionobject because of the abstract nature of theCollectionframework. Each column value should be fully represented in either a general purposeCollectionimplementation or a specializedCollectionimplementation, such as aVectorobject. An SQLNULLcolumn value must be represented as anullin the Java programming language.The standard reference implementation uses a
Vectorobject to contain the column values, and it is expected that most implementations will do the same. If aVectorobject is used, it size must be exactly equal to the number of rows in thisCachedRowSetobject.- Parameters:
column- aStringobject giving the name of the column whose values are to be represented in a collection- Returns:
- a
Collectionobject that contains the values stored in the specified column of thisCachedRowSetobject - Throws:
SQLException- if an error occurs generating the collection or an invalid column id is provided- See Also:
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getSyncProvider
Retrieves theSyncProviderimplementation for thisCachedRowSetobject. Internally, this method is used by a rowset to trigger read or write actions between the rowset and the data source. For example, a rowset may need to get a handle on the rowset reader (RowSetReaderobject) from theSyncProviderto allow the rowset to be populated.RowSetReader rowsetReader = null; SyncProvider provider = SyncFactory.getInstance("javax.sql.rowset.provider.RIOptimisticProvider"); if (provider instanceof RIOptimisticProvider) { rowsetReader = provider.getRowSetReader(); }Assuming rowsetReader is a private, accessible field within the rowset implementation, when an application calls theexecutemethod, it in turn calls on the reader'sreadDatamethod to populate theRowSetobject.rowsetReader.readData((RowSetInternal)this);In addition, an application can use the
SyncProviderobject returned by this method to call methods that return information about theSyncProviderobject, including information about the vendor, version, provider identification, synchronization grade, and locks it currently has set.- Returns:
- the
SyncProviderobject that was set when the rowset was instantiated, or if none was set, the default provider - Throws:
SQLException- if an error occurs while returning theSyncProviderobject- See Also:
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setSyncProvider
Sets theSyncProviderobject for thisCachedRowSetobject to the one specified. This method allows theSyncProviderobject to be reset.A
CachedRowSetimplementation should always be instantiated with an availableSyncProvidermechanism, but there are cases where resetting theSyncProviderobject is desirable or necessary. For example, an application might want to use the defaultSyncProviderobject for a time and then choose to use a provider that has more recently become available and better fits its needs.Resetting the
SyncProviderobject causes theRowSetobject to request a newSyncProviderimplementation from theSyncFactory. This has the effect of resetting all previous connections and relationships with the originating data source and can potentially drastically change the synchronization behavior of a disconnected rowset.- Parameters:
provider- aStringobject giving the fully qualified class name of aSyncProviderimplementation- Throws:
SQLException- if an error occurs while attempting to reset theSyncProviderimplementation- See Also:
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size
int size()Returns the number of rows in thisCachedRowSetobject.- Returns:
- number of rows in the rowset
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setMetaData
Sets the metadata for thisCachedRowSetobject with the givenRowSetMetaDataobject. When aRowSetReaderobject is reading the contents of a rowset, it creates aRowSetMetaDataobject and initializes it using the methods in theRowSetMetaDataimplementation. The reference implementation uses theRowSetMetaDataImplclass. When the reader has completed reading the rowset contents, this method is called internally to pass theRowSetMetaDataobject to the rowset.- Parameters:
md- aRowSetMetaDataobject containing metadata about the columns in thisCachedRowSetobject- Throws:
SQLException- if invalid metadata is supplied to the rowset
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getOriginal
Returns aResultSetobject containing the original value of thisCachedRowSetobject.The cursor for the
ResultSetobject should be positioned before the first row. In addition, the returnedResultSetobject should have the following properties:- ResultSet.TYPE_SCROLL_INSENSITIVE
- ResultSet.CONCUR_UPDATABLE
The original value for a
RowSetobject is the value it had before the last synchronization with the underlying data source. If there have been no synchronizations, the original value will be the value with which theRowSetobject was populated. This method is called internally when an application calls the methodacceptChangesand theSyncProviderobject has been implemented to check for conflicts. If this is the case, the writer compares the original value with the value currently in the data source to check for conflicts.- Returns:
- a
ResultSetobject that contains the original value for thisCachedRowSetobject - Throws:
SQLException- if an error occurs producing theResultSetobject
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getOriginalRow
Returns aResultSetobject containing the original value for the current row only of thisCachedRowSetobject.The cursor for the
ResultSetobject should be positioned before the first row. In addition, the returnedResultSetobject should have the following properties:- ResultSet.TYPE_SCROLL_INSENSITIVE
- ResultSet.CONCUR_UPDATABLE
- Returns:
- the original result set of the row
- Throws:
SQLException- if there is no current row- See Also:
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setOriginalRow
Sets the current row in thisCachedRowSetobject as the original row.This method is called internally after the any modified values in the current row have been synchronized with the data source. The current row must be tagged as no longer inserted, deleted or updated.
A call to
setOriginalRowis irreversible.- Throws:
SQLException- if there is no current row or an error is encountered resetting the contents of the original row- See Also:
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getTableName
Returns an identifier for the object (table) that was used to create thisCachedRowSetobject. This name may be set on multiple occasions, and the specification imposes no limits on how many times this may occur or whether standard implementations should keep track of previous table names.- Returns:
- a
Stringobject giving the name of the table that is the source of data for thisCachedRowSetobject ornullif no name has been set for the table - Throws:
SQLException- if an error is encountered returning the table name- See Also:
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setTableName
Sets the identifier for the table from which thisCachedRowSetobject was derived to the given table name. The writer uses this name to determine which table to use when comparing the values in the data source with theCachedRowSetobject's values during a synchronization attempt. The table identifier also indicates where modified values from thisCachedRowSetobject should be written.The implementation of this
CachedRowSetobject may obtain the the name internally from theRowSetMetaDataImplobject.- Parameters:
tabName- aStringobject identifying the table from which thisCachedRowSetobject was derived; cannot benullbut may be an empty string- Throws:
SQLException- if an error is encountered naming the table or tabName isnull- See Also:
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getKeyColumns
Returns an array containing one or more column numbers indicating the columns that form a key that uniquely identifies a row in thisCachedRowSetobject.- Returns:
- an array containing the column number or numbers that indicate which columns
constitute a primary key
for a row in this
CachedRowSetobject. This array should be empty if no columns are representative of a primary key. - Throws:
SQLException- if thisCachedRowSetobject is empty- See Also:
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setKeyColumns
Sets thisCachedRowSetobject'skeyColsfield with the given array of column numbers, which forms a key for uniquely identifying a row in thisCachedRowSetobject.If a
CachedRowSetobject becomes part of aJoinRowSetobject, the keys defined by this method and the resulting constraints are maintained if the columns designated as key columns also become match columns.- Parameters:
keys- an array ofintindicating the columns that form a primary key for thisCachedRowSetobject; every element in the array must be greater than0and less than or equal to the number of columns in this rowset- Throws:
SQLException- if any of the numbers in the given array are not valid for this rowset- See Also:
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createCopy
Creates aRowSetobject that is a deep copy of the data in thisCachedRowSetobject. In contrast to theRowSetobject generated from acreateSharedcall, updates made to the copy of the originalRowSetobject must not be visible to the originalRowSetobject. Also, any event listeners that are registered with the originalRowSetmust not have scope over the newRowSetcopies. In addition, any constraint restrictions established must be maintained.- Returns:
- a new
RowSetobject that is a deep copy of thisCachedRowSetobject and is completely independent of thisCachedRowSetobject - Throws:
SQLException- if an error occurs in generating the copy of the of thisCachedRowSetobject- See Also:
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createCopySchema
Creates aCachedRowSetobject that is an empty copy of thisCachedRowSetobject. The copy must not contain any contents but only represent the table structure of the originalCachedRowSetobject. In addition, primary or foreign key constraints set in the originatingCachedRowSetobject must be equally enforced in the new emptyCachedRowSetobject. In contrast to theRowSetobject generated from acreateSharedmethod call, updates made to a copy of thisCachedRowSetobject with thecreateCopySchemamethod must not be visible to it.Applications can form a
WebRowSetobject from theCachedRowSetobject returned by this method in order to export theRowSetschema definition to XML for future use.- Returns:
- An empty copy of this
CachedRowSetobject - Throws:
SQLException- if an error occurs in cloning the structure of thisCachedRowSetobject- See Also:
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createCopyNoConstraints
Creates aCachedRowSetobject that is a deep copy of thisCachedRowSetobject's data but is independent of it. In contrast to theRowSetobject generated from acreateSharedmethod call, updates made to a copy of thisCachedRowSetobject must not be visible to it. Also, any event listeners that are registered with thisCachedRowSetobject must not have scope over the newRowSetobject. In addition, any constraint restrictions established for thisCachedRowSetobject must not be maintained in the copy.- Returns:
- a new
CachedRowSetobject that is a deep copy of thisCachedRowSetobject and is completely independent of thisCachedRowSetobject - Throws:
SQLException- if an error occurs in generating the copy of the of thisCachedRowSetobject- See Also:
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getRowSetWarnings
Retrieves the first warning reported by calls on thisRowSetobject. Subsequent warnings on thisRowSetobject will be chained to theRowSetWarningobject that this method returns. The warning chain is automatically cleared each time a new row is read. This method may not be called on a RowSet object that has been closed; doing so will cause aSQLExceptionto be thrown.- Returns:
- RowSetWarning the first
RowSetWarningobject reported or null if there are none - Throws:
SQLException- if this method is called on a closed RowSet- See Also:
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getShowDeleted
Retrieves abooleanindicating whether rows marked for deletion appear in the set of current rows. Iftrueis returned, deleted rows are visible with the current rows. Iffalseis returned, rows are not visible with the set of current rows. The default value isfalse.Standard rowset implementations may choose to restrict this behavior due to security considerations or to better fit certain deployment scenarios. This is left as implementation defined and does not represent standard behavior.
Note: Allowing deleted rows to remain visible complicates the behavior of some standard JDBC
RowSetImplementations methods. However, most rowset users can simply ignore this extra detail because only very specialized applications will likely want to take advantage of this feature.- Returns:
trueif deleted rows are visible;falseotherwise- Throws:
SQLException- if a rowset implementation is unable to to determine whether rows marked for deletion are visible- See Also:
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setShowDeleted
Sets the propertyshowDeletedto the givenbooleanvalue, which determines whether rows marked for deletion appear in the set of current rows. If the value is set totrue, deleted rows are immediately visible with the set of current rows. If the value is set tofalse, the deleted rows are set as invisible with the current set of rows.Standard rowset implementations may choose to restrict this behavior due to security considerations or to better fit certain deployment scenarios. This is left as implementations defined and does not represent standard behavior.
- Parameters:
b-trueif deleted rows should be shown;falseotherwise- Throws:
SQLException- if a rowset implementation is unable to to reset whether deleted rows should be visible- See Also:
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commit
EachCachedRowSetobject'sSyncProvidercontains aConnectionobject from theResultSetor JDBC properties passed to it's constructors. This method wraps theConnectioncommit method to allow flexible auto commit or non auto commit transactional control support.Makes all changes that are performed by the
acceptChanges()method since the previous commit/rollback permanent. This method should be used only when auto-commit mode has been disabled.- Throws:
SQLException- if a database access error occurs or this Connection object within thisCachedRowSetis in auto-commit mode- See Also:
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rollback
EachCachedRowSetobject'sSyncProvidercontains aConnectionobject from the originalResultSetor JDBC properties passed to it.Undoes all changes made in the current transaction. This method should be used only when auto-commit mode has been disabled.
- Throws:
SQLException- if a database access error occurs or this Connection object within thisCachedRowSetis in auto-commit mode.
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rollback
EachCachedRowSetobject'sSyncProvidercontains aConnectionobject from the originalResultSetor JDBC properties passed to it.Undoes all changes made in the current transaction back to the last
Savepointtransaction marker. This method should be used only when auto-commit mode has been disabled.- Parameters:
s- ASavepointtransaction marker- Throws:
SQLException- if a database access error occurs or this Connection object within thisCachedRowSetis in auto-commit mode.
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rowSetPopulated
Notifies registered listeners that a RowSet object in the given RowSetEvent object has populated a number of additional rows. ThenumRowsparameter ensures that this event will only be fired everynumRow.The source of the event can be retrieved with the method event.getSource.
- Parameters:
event- aRowSetEventobject that contains theRowSetobject that is the source of the eventsnumRows- when populating, the number of rows interval on which theCachedRowSetpopulated should fire; the default value is zero; cannot be less thanfetchSizeor zero- Throws:
SQLException-numRows < 0 or numRows < getFetchSize()
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populate
Populates thisCachedRowSetobject with data from the givenResultSetobject. While related to thepopulate(ResultSet)method, an additional parameter is provided to allow starting position within theResultSetfrom where to populate the CachedRowSet instance.This method can be used as an alternative to the
executemethod when an application has a connection to an openResultSetobject. Using the methodpopulatecan be more efficient than using the version of theexecutemethod that takes no parameters because it does not open a new connection and re-execute thisCachedRowSetobject's command. Using thepopulatemethod is more a matter of convenience when compared to using the version ofexecutethat takes aResultSetobject.- Parameters:
rs- theResultSetobject containing the data to be read into thisCachedRowSetobjectstartRow- the position in theResultSetfrom where to start populating the records in thisCachedRowSet- Throws:
SQLException- if a nullResultSetobject is supplied or thisCachedRowSetobject cannot retrieve the associatedResultSetMetaDataobject- See Also:
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setPageSize
Sets theCachedRowSetobject's page-size. ACachedRowSetmay be configured to populate itself in page-size sized batches of rows. When eitherpopulate()orexecute()are called, theCachedRowSetfetches an additional page according to the original SQL query used to populate the RowSet.- Parameters:
size- the page-size of theCachedRowSet- Throws:
SQLException- if an error occurs setting theCachedRowSetpage size or if the page size is less than 0.
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getPageSize
int getPageSize()Returns the page-size for theCachedRowSetobject- Returns:
- an
intpage size
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nextPage
Increments the current page of theCachedRowSet. This causes theCachedRowSetimplementation to fetch the next page-size rows and populate the RowSet, if remaining rows remain within scope of the original SQL query used to populated the RowSet.- Returns:
- true if more pages exist; false if this is the last page
- Throws:
SQLException- if an error occurs fetching the next page, or if this method is called prematurely before populate or execute.
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previousPage
Decrements the current page of theCachedRowSet. This causes theCachedRowSetimplementation to fetch the previous page-size rows and populate the RowSet. The amount of rows returned in the previous page must always remain within scope of the original SQL query used to populate the RowSet.- Returns:
- true if the previous page is successfully retrieved; false if this is the first page.
- Throws:
SQLException- if an error occurs fetching the previous page, or if this method is called prematurely before populate or execute.
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