Class TransformService
- java.lang.Object
-
- javax.xml.crypto.dsig.TransformService
- All Implemented Interfaces:
-
AlgorithmMethod
,Transform
,XMLStructure
public abstract class TransformService extends Object implements Transform
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.
- Since:
- 1.6
Field Summary
Fields declared in interface javax.xml.crypto.dsig.Transform
BASE64, ENVELOPED, XPATH, XPATH2, XSLT
Constructor Summary
Modifier | Constructor | Description |
---|---|---|
protected | TransformService() | Default constructor, for invocation by subclasses. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
String | getAlgorithm() | Returns the URI of the algorithm supported by this |
static TransformService | getInstance(String algorithm,
String mechanismType) | Returns a |
static TransformService | getInstance(String algorithm,
String mechanismType,
String provider) | Returns a |
static TransformService | getInstance(String algorithm,
String mechanismType,
Provider provider) | Returns a |
String | getMechanismType() | Returns the mechanism type supported by this |
Provider | getProvider() | Returns the provider of this |
abstract void | init(TransformParameterSpec params) | Initializes this |
abstract void | init(XMLStructure parent,
XMLCryptoContext context) | Initializes this |
abstract void | marshalParams(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, wait
Methods declared in interface javax.xml.crypto.dsig.Transform
getParameterSpec, transform, transform
Methods declared in interface javax.xml.crypto.XMLStructure
isFeatureSupported
Constructor Detail
TransformService
protected TransformService()
Default constructor, for invocation by subclasses.
Method Detail
getInstance
public static TransformService getInstance(String algorithm, String mechanismType) throws NoSuchAlgorithmException
Returns a TransformService
that 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 TransformService
implementation of the desired algorithm and MechanismType
service attribute. It traverses the list of registered security Provider
s, starting with the most preferred Provider
. A new TransformService
object from the first Provider
that 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.preferred
Security
property 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 -
mechanismType
- the type of the XML processing mechanism and representation - Returns:
- a new
TransformService
- Throws:
-
NullPointerException
- ifalgorithm
ormechanismType
isnull
-
NoSuchAlgorithmException
- if noProvider
supports aTransformService
implementation for the specified algorithm and mechanism type - See Also:
Provider
getInstance
public static TransformService getInstance(String algorithm, String mechanismType, Provider provider) throws NoSuchAlgorithmException
Returns a TransformService
that supports the specified algorithm URI (ex: Transform.XPATH2
) and mechanism type (ex: DOM) as supplied by the specified provider. Note that the specified Provider
object does not have to be registered in the provider list.
- Parameters:
-
algorithm
- the URI of the algorithm -
mechanismType
- the type of the XML processing mechanism and representation -
provider
- theProvider
object - Returns:
- a new
TransformService
- Throws:
-
NullPointerException
- ifprovider
,algorithm
, ormechanismType
isnull
-
NoSuchAlgorithmException
- if aTransformService
implementation for the specified algorithm and mechanism type is not available from the specifiedProvider
object - See Also:
Provider
getInstance
public static TransformService getInstance(String algorithm, String mechanismType, String provider) throws NoSuchAlgorithmException, NoSuchProviderException
Returns a TransformService
that 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 -
mechanismType
- the type of the XML processing mechanism and representation -
provider
- the string name of the provider - Returns:
- a new
TransformService
- Throws:
-
NoSuchProviderException
- if the specified provider is not registered in the security provider list -
NullPointerException
- ifprovider
,mechanismType
, oralgorithm
isnull
-
NoSuchAlgorithmException
- if aTransformService
implementation for the specified algorithm and mechanism type is not available from the specified provider - See Also:
Provider
getMechanismType
public final String getMechanismType()
Returns the mechanism type supported by this TransformService
.
- Returns:
- the mechanism type
getAlgorithm
public final String getAlgorithm()
Returns the URI of the algorithm supported by this TransformService
.
- Specified by:
-
getAlgorithm
in interfaceAlgorithmMethod
- Returns:
- the algorithm URI
getProvider
public final Provider getProvider()
Returns the provider of this TransformService
.
- Returns:
- the provider
init
public abstract void init(TransformParameterSpec params) throws InvalidAlgorithmParameterException
Initializes this TransformService
with the specified parameters.
If the parameters exist in XML form, the init(XMLStructure, XMLCryptoContext)
method should be used to initialize the TransformService
.
- Parameters:
-
params
- the algorithm parameters (may benull
if not required or optional) - Throws:
-
InvalidAlgorithmParameterException
- if the specified parameters are invalid for this algorithm
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 to -
context
- theXMLCryptoContext
containing additional context (may benull
if not applicable) - Throws:
-
ClassCastException
- if the type ofparent
orcontext
is not compatible with thisTransformService
-
NullPointerException
- ifparent
isnull
-
MarshalException
- if the parameters cannot be marshalled
init
public abstract void init(XMLStructure parent, XMLCryptoContext context) throws InvalidAlgorithmParameterException
Initializes this TransformService
with the specified parameters and document context.
- Parameters:
-
parent
- a mechanism-specific structure containing the parent structure -
context
- theXMLCryptoContext
containing additional context (may benull
if not applicable) - Throws:
-
ClassCastException
- if the type ofparent
orcontext
is not compatible with thisTransformService
-
NullPointerException
- ifparent
isnull
-
InvalidAlgorithmParameterException
- if the specified parameters are invalid for this algorithm