Class TransformService
- All Implemented Interfaces:
AlgorithmMethod,Transform,XMLStructure
Each instance of TransformService supports a specific
transform or canonicalization algorithm and XML mechanism type. To create a
TransformService, call one of the static
getInstance methods, passing in the algorithm URI and
XML mechanism type desired, for example:
TransformService ts = TransformService.getInstance(Transform.XPATH2, "DOM");
TransformService implementations are registered and loaded
using the Provider mechanism. Each
TransformService service provider implementation should include
a MechanismType service attribute that identifies the XML
mechanism type that it supports. If the attribute is not specified,
"DOM" is assumed. For example, a service provider that supports the
XPath Filter 2 Transform and DOM mechanism would be specified in the
Provider subclass as:
put("TransformService." + Transform.XPATH2,
"org.example.XPath2TransformService");
put("TransformService." + Transform.XPATH2 + " MechanismType", "DOM");
TransformService implementations that support the DOM
mechanism type must abide by the DOM interoperability requirements defined
in the DOM Mechanism
Requirements. See the TransformService section in the
Java Security Standard Algorithm Names Specification for a list of
standard algorithm URIs and mechanism types.
Once a TransformService has been created, it can be used
to process Transform or CanonicalizationMethod
objects. If the Transform or CanonicalizationMethod
exists in XML form (for example, when validating an existing
XMLSignature), the init(XMLStructure, XMLCryptoContext)
method must be first called to initialize the transform and provide document
context (even if there are no parameters). Alternatively, if the
Transform or CanonicalizationMethod is being
created from scratch, the init(TransformParameterSpec) method
is called to initialize the transform with parameters and the
marshalParams method is called to marshal the
parameters to XML and provide the transform with document context. Finally,
the transform method is called to perform the
transformation.
Concurrent Access
The static methods of this class are guaranteed to be thread-safe. Multiple threads may concurrently invoke the static methods defined in this class with no ill effects.
However, this is not true for the non-static methods defined by this
class. Unless otherwise documented by a specific provider, threads that
need to access a single TransformService instance
concurrently should synchronize amongst themselves and provide the
necessary locking. Multiple threads each manipulating a different
TransformService instance need not synchronize.
- Since:
- 1.6
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Field Summary
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Constructor Summary
ConstructorsModifierConstructorDescriptionprotectedDefault constructor, for invocation by subclasses. -
Method Summary
Modifier and TypeMethodDescriptionfinal StringReturns the URI of the algorithm supported by thisTransformService.static TransformServicegetInstance(String algorithm, String mechanismType) Returns aTransformServicethat supports the specified algorithm URI (ex:Transform.XPATH2) and mechanism type (ex: DOM).static TransformServicegetInstance(String algorithm, String mechanismType, String provider) Returns aTransformServicethat supports the specified algorithm URI (ex:Transform.XPATH2) and mechanism type (ex: DOM) as supplied by the specified provider.static TransformServicegetInstance(String algorithm, String mechanismType, Provider provider) Returns aTransformServicethat supports the specified algorithm URI (ex:Transform.XPATH2) and mechanism type (ex: DOM) as supplied by the specified provider.final StringReturns the mechanism type supported by thisTransformService.final ProviderReturns the provider of thisTransformService.abstract voidinit(TransformParameterSpec params) Initializes thisTransformServicewith the specified parameters.abstract voidinit(XMLStructure parent, XMLCryptoContext context) Initializes thisTransformServicewith the specified parameters and document context.abstract voidmarshalParams(XMLStructure parent, XMLCryptoContext context) Marshals the algorithm-specific parameters.Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitMethods declared in interface javax.xml.crypto.dsig.Transform
getParameterSpec, transform, transformMethods declared in interface javax.xml.crypto.XMLStructure
isFeatureSupported
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Constructor Details
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TransformService
protected TransformService()Default constructor, for invocation by subclasses.
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Method Details
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getInstance
public static TransformService getInstance(String algorithm, String mechanismType) throws NoSuchAlgorithmException Returns aTransformServicethat supports the specified algorithm URI (ex:Transform.XPATH2) and mechanism type (ex: DOM).This method uses the standard JCA provider lookup mechanism to locate and instantiate a
TransformServiceimplementation of the desired algorithm andMechanismTypeservice attribute. It traverses the list of registered securityProviders, starting with the most preferredProvider. A newTransformServiceobject from the firstProviderthat supports the specified algorithm and mechanism type is returned.Note that the list of registered providers may be retrieved via the
Security.getProviders()method.- Implementation Note:
- The JDK Reference Implementation additionally uses the
jdk.security.provider.preferredSecurityproperty to determine the preferred provider order for the specified algorithm. This may be different than the order of providers returned bySecurity.getProviders(). - Parameters:
algorithm- the URI of the algorithm. See theTransformServicesection in the Java Security Standard Algorithm Names Specification for a list of standard transform algorithms.mechanismType- the type of the XML processing mechanism and representation. See theTransformServicesection in the Java Security Standard Algorithm Names Specification for a list of standard mechanism types.- Returns:
- a new
TransformService - Throws:
NullPointerException- ifalgorithmormechanismTypeisnullNoSuchAlgorithmException- if noProvidersupports aTransformServiceimplementation for the specified algorithm and mechanism type- See Also:
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getInstance
public static TransformService getInstance(String algorithm, String mechanismType, Provider provider) throws NoSuchAlgorithmException Returns aTransformServicethat supports the specified algorithm URI (ex:Transform.XPATH2) and mechanism type (ex: DOM) as supplied by the specified provider. Note that the specifiedProviderobject does not have to be registered in the provider list.- Parameters:
algorithm- the URI of the algorithm. See theTransformServicesection in the Java Security Standard Algorithm Names Specification for a list of standard transform algorithms.mechanismType- the type of the XML processing mechanism and representation. See theTransformServicesection in the Java Security Standard Algorithm Names Specification for a list of standard mechanism types.provider- theProviderobject- Returns:
- a new
TransformService - Throws:
NullPointerException- ifprovider,algorithm, ormechanismTypeisnullNoSuchAlgorithmException- if aTransformServiceimplementation for the specified algorithm and mechanism type is not available from the specifiedProviderobject- See Also:
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getInstance
public static TransformService getInstance(String algorithm, String mechanismType, String provider) throws NoSuchAlgorithmException, NoSuchProviderException Returns aTransformServicethat supports the specified algorithm URI (ex:Transform.XPATH2) and mechanism type (ex: DOM) as supplied by the specified provider. The specified provider must be registered in the security provider list.Note that the list of registered providers may be retrieved via the
Security.getProviders()method.- Parameters:
algorithm- the URI of the algorithm. See theTransformServicesection in the Java Security Standard Algorithm Names Specification for a list of standard transform algorithms.mechanismType- the type of the XML processing mechanism and representation. See theTransformServicesection in the Java Security Standard Algorithm Names Specification for a list of standard mechanism types.provider- the string name of the provider- Returns:
- a new
TransformService - Throws:
NoSuchProviderException- if the specified provider is not registered in the security provider listNullPointerException- ifprovider,mechanismType, oralgorithmisnullNoSuchAlgorithmException- if aTransformServiceimplementation for the specified algorithm and mechanism type is not available from the specified provider- See Also:
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getMechanismType
Returns the mechanism type supported by thisTransformService.- Returns:
- the mechanism type
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getAlgorithm
Returns the URI of the algorithm supported by thisTransformService.- Specified by:
getAlgorithmin interfaceAlgorithmMethod- Returns:
- the algorithm URI
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getProvider
Returns the provider of thisTransformService.- Returns:
- the provider
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init
Initializes thisTransformServicewith the specified parameters.If the parameters exist in XML form, the
init(XMLStructure, XMLCryptoContext)method should be used to initialize theTransformService.- Parameters:
params- the algorithm parameters (may benullif not required or optional)- Throws:
InvalidAlgorithmParameterException- if the specified parameters are invalid for this algorithm
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marshalParams
public abstract void marshalParams(XMLStructure parent, XMLCryptoContext context) throws MarshalException Marshals the algorithm-specific parameters. If there are no parameters to be marshalled, this method returns without throwing an exception.- Parameters:
parent- a mechanism-specific structure containing the parent node that the marshalled parameters should be appended tocontext- theXMLCryptoContextcontaining additional context (may benullif not applicable)- Throws:
ClassCastException- if the type ofparentorcontextis not compatible with thisTransformServiceNullPointerException- ifparentisnullMarshalException- if the parameters cannot be marshalled
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init
public abstract void init(XMLStructure parent, XMLCryptoContext context) throws InvalidAlgorithmParameterException Initializes thisTransformServicewith the specified parameters and document context.- Parameters:
parent- a mechanism-specific structure containing the parent structurecontext- theXMLCryptoContextcontaining additional context (may benullif not applicable)- Throws:
ClassCastException- if the type ofparentorcontextis not compatible with thisTransformServiceNullPointerException- ifparentisnullInvalidAlgorithmParameterException- if the specified parameters are invalid for this algorithm
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