TransformService

Class Overview

A Service Provider Interface for transform and canonicalization algorithms.

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 section of the API overview. See the Service Providers section of the API overview for a list of standard 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.

Summary

[Expand] Inherited Constants
From interface javax.xml.crypto.dsig.Transform String BASE64 The Base64 transform algorithm URI. String ENVELOPED The Enveloped Signature transform algorithm URI. String XPATH The XPath transform algorithm URI. String XPATH2 The XPath Filter 2 transform algorithm URI. String XSLT The XSLT transform algorithm URI.

Protected Constructors
	TransformService() Default constructor, for invocation by subclasses.

Public Methods
final String	getAlgorithm() Returns the URI of the algorithm supported by this TransformService.
static TransformService	getInstance(String algorithm, String mechanismType, String provider) Returns a TransformService that supports the specified algorithm URI (ex: XPATH2) and mechanism type (ex: DOM) as supplied by the specified provider.
static TransformService	getInstance(String algorithm, String mechanismType) Returns a TransformService that supports the specified algorithm URI (ex: XPATH2) and mechanism type (ex: DOM).
static TransformService	getInstance(String algorithm, String mechanismType, Provider provider) Returns a TransformService that supports the specified algorithm URI (ex: XPATH2) and mechanism type (ex: DOM) as supplied by the specified provider.
final String	getMechanismType() Returns the mechanism type supported by this TransformService.
final Provider	getProvider() Returns the provider of this TransformService.
abstract void	init(TransformParameterSpec params) Initializes this TransformService with the specified parameters.
abstract void	init(XMLStructure parent, XMLCryptoContext context) Initializes this TransformService with the specified parameters and document context.
abstract void	marshalParams(XMLStructure parent, XMLCryptoContext context) Marshals the algorithm-specific parameters.

[Expand] Inherited Methods
From class java.lang.Object Object clone() Creates and returns a copy of this object. boolean equals(Object obj) Indicates whether some other object is "equal to" this one. void finalize() Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. final Class<?> getClass() Returns the runtime class of this Object. int hashCode() Returns a hash code value for the object. final void notify() Wakes up a single thread that is waiting on this object's monitor. final void notifyAll() Wakes up all threads that are waiting on this object's monitor. String toString() Returns a string representation of the object. final void wait() Causes the current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object. final void wait(long timeout, int nanos) Causes the current thread to wait until another thread invokes the notify() method or the notifyAll() method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed. final void wait(long timeout) Causes the current thread to wait until either another thread invokes the notify() method or the notifyAll() method for this object, or a specified amount of time has elapsed.
From interface javax.xml.crypto.AlgorithmMethod abstract String getAlgorithm() Returns the algorithm URI of this AlgorithmMethod. abstract AlgorithmParameterSpec getParameterSpec() Returns the algorithm parameters of this AlgorithmMethod.
From interface javax.xml.crypto.XMLStructure abstract boolean isFeatureSupported(String feature) Indicates whether a specified feature is supported.
From interface javax.xml.crypto.dsig.Transform abstract AlgorithmParameterSpec getParameterSpec() Returns the algorithm-specific input parameters associated with this Transform. abstract Data transform(Data data, XMLCryptoContext context) Transforms the specified data using the underlying transform algorithm. abstract Data transform(Data data, XMLCryptoContext context, OutputStream os) Transforms the specified data using the underlying transform algorithm.