Transformer

public abstract class Transformer
extends Object

java.lang.Object
   ↳ javax.xml.transform.Transformer


An instance of this abstract class can transform a source tree into a result tree.

An instance of this class can be obtained with the TransformerFactory.newTransformer method. This instance may then be used to process XML from a variety of sources and write the transformation output to a variety of sinks.

An object of this class may not be used in multiple threads running concurrently. Different Transformers may be used concurrently by different threads.

A Transformer may be used multiple times. Parameters and output properties are preserved across transformations.

Summary

Protected constructors

Transformer()

Default constructor is protected on purpose.

Public methods

abstract void clearParameters()

Clear all parameters set with setParameter.

abstract ErrorListener getErrorListener()

Get the error event handler in effect for the transformation.

abstract Properties getOutputProperties()

Get a copy of the output properties for the transformation.

abstract String getOutputProperty(String name)

Get an output property that is in effect for the transformer.

abstract Object getParameter(String name)

Get a parameter that was explicitly set with setParameter.

abstract URIResolver getURIResolver()

Get an object that will be used to resolve URIs used in document().

void reset()

Reset this Transformer to its original configuration.

abstract void setErrorListener(ErrorListener listener)

Set the error event listener in effect for the transformation.

abstract void setOutputProperties(Properties oformat)

Set the output properties for the transformation.

abstract void setOutputProperty(String name, String value)

Set an output property that will be in effect for the transformation.

abstract void setParameter(String name, Object value)

Add a parameter for the transformation.

abstract void setURIResolver(URIResolver resolver)

Set an object that will be used to resolve URIs used in document().

abstract void transform(Source xmlSource, Result outputTarget)

Transform the XML Source to a Result.

Inherited methods

Protected constructors

Transformer

Added in API level 8
protected Transformer ()

Default constructor is protected on purpose.

Public methods

clearParameters

Added in API level 8
public abstract void clearParameters ()

Clear all parameters set with setParameter.

getErrorListener

Added in API level 8
public abstract ErrorListener getErrorListener ()

Get the error event handler in effect for the transformation. Implementations must provide a default error listener.

Returns
ErrorListener The current error handler, which should never be null.

getOutputProperties

Added in API level 8
public abstract Properties getOutputProperties ()

Get a copy of the output properties for the transformation.

The properties returned should contain properties set by the user, and properties set by the stylesheet, and these properties are "defaulted" by default properties specified by section 16 of the XSL Transformations (XSLT) W3C Recommendation. The properties that were specifically set by the user or the stylesheet should be in the base Properties list, while the XSLT default properties that were not specifically set should be the default Properties list. Thus, getOutputProperties().getProperty(String key) will obtain any property in that was set by setOutputProperty(String, String), setOutputProperties(Properties), in the stylesheet, or the default properties, while getOutputProperties().get(String key) will only retrieve properties that were explicitly set by setOutputProperty(String, String), setOutputProperties(Properties), or in the stylesheet.

Note that mutation of the Properties object returned will not effect the properties that the transformer contains.

If any of the argument keys are not recognized and are not namespace qualified, the property will be ignored and not returned. In other words the behavior is not orthogonal with setOutputProperties.

Returns
Properties A copy of the set of output properties in effect for the next transformation.

getOutputProperty

Added in API level 8
public abstract String getOutputProperty (String name)

Get an output property that is in effect for the transformer. The property specified may be a property that was set with setOutputProperty, or it may be a property specified in the stylesheet.

Parameters
name String: A non-null String that specifies an output property name, which may be namespace qualified.

Returns
String The string value of the output property, or null if no property was found.

Throws
IllegalArgumentException If the property is not supported.

See also:

getParameter

Added in API level 8
public abstract Object getParameter (String name)

Get a parameter that was explicitly set with setParameter.

This method does not return a default parameter value, which cannot be determined until the node context is evaluated during the transformation process.

Parameters
name String: of Object to get

Returns
Object A parameter that has been set with setParameter.

getURIResolver

Added in API level 8
public abstract URIResolver getURIResolver ()

Get an object that will be used to resolve URIs used in document().

Returns
URIResolver An object that implements the URIResolver interface, or null.

reset

Added in API level 8
public void reset ()

Reset this Transformer to its original configuration.

Transformer is reset to the same state as when it was created with TransformerFactory.newTransformer(), TransformerFactory.newTransformer(Source source) or Templates.newTransformer(). reset() is designed to allow the reuse of existing Transformers thus saving resources associated with the creation of new Transformers.

The reset Transformer is not guaranteed to have the same URIResolver or ErrorListener Objects, e.g. Object.equals(Object obj). It is guaranteed to have a functionally equal URIResolver and ErrorListener.

setErrorListener

Added in API level 8
public abstract void setErrorListener (ErrorListener listener)

Set the error event listener in effect for the transformation.

Parameters
listener ErrorListener: The new error listener.

Throws
IllegalArgumentException if listener is null.

setOutputProperties

Added in API level 8
public abstract void setOutputProperties (Properties oformat)

Set the output properties for the transformation. These properties will override properties set in the Templates with xsl:output.

If argument to this function is null, any properties previously set are removed, and the value will revert to the value defined in the templates object.

Pass a qualified property key name as a two-part string, the namespace URI enclosed in curly braces ({}), followed by the local name. If the name has a null URL, the String only contain the local name. An application can safely check for a non-null URI by testing to see if the first character of the name is a '{' character.

For example, if a URI and local name were obtained from an element defined with <xyz:foo xmlns:xyz="http://xyz.foo.com/yada/baz.html"/>, then the qualified name would be "{http://xyz.foo.com/yada/baz.html}foo". Note that no prefix is used.

An IllegalArgumentException is thrown if any of the argument keys are not recognized and are not namespace qualified.

Parameters
oformat Properties: A set of output properties that will be used to override any of the same properties in affect for the transformation.

setOutputProperty

Added in API level 8
public abstract void setOutputProperty (String name, 
                String value)

Set an output property that will be in effect for the transformation.

Pass a qualified property name as a two-part string, the namespace URI enclosed in curly braces ({}), followed by the local name. If the name has a null URL, the String only contain the local name. An application can safely check for a non-null URI by testing to see if the first character of the name is a '{' character.

For example, if a URI and local name were obtained from an element defined with <xyz:foo xmlns:xyz="http://xyz.foo.com/yada/baz.html"/>, then the qualified name would be "{http://xyz.foo.com/yada/baz.html}foo". Note that no prefix is used.

The Properties object that was passed to setOutputProperties(Properties) won't be effected by calling this method.

Parameters
name String: A non-null String that specifies an output property name, which may be namespace qualified.

value String: The non-null string value of the output property.

Throws
IllegalArgumentException If the property is not supported, and is not qualified with a namespace.

See also:

setParameter

Added in API level 8
public abstract void setParameter (String name, 
                Object value)

Add a parameter for the transformation.

Pass a qualified name as a two-part string, the namespace URI enclosed in curly braces ({}), followed by the local name. If the name has a null URL, the String only contain the local name. An application can safely check for a non-null URI by testing to see if the first character of the name is a '{' character.

For example, if a URI and local name were obtained from an element defined with <xyz:foo xmlns:xyz="http://xyz.foo.com/yada/baz.html"/>, then the qualified name would be "{http://xyz.foo.com/yada/baz.html}foo". Note that no prefix is used.

Parameters
name String: The name of the parameter, which may begin with a namespace URI in curly braces ({}).

value Object: The value object. This can be any valid Java object. It is up to the processor to provide the proper object coercion or to simply pass the object on for use in an extension.

Throws
NullPointerException If value is null.

setURIResolver

Added in API level 8
public abstract void setURIResolver (URIResolver resolver)

Set an object that will be used to resolve URIs used in document().

If the resolver argument is null, the URIResolver value will be cleared and the transformer will no longer have a resolver.

Parameters
resolver URIResolver: An object that implements the URIResolver interface, or null.

transform

Added in API level 8
public abstract void transform (Source xmlSource, 
                Result outputTarget)

Transform the XML Source to a Result. Specific transformation behavior is determined by the settings of the TransformerFactory in effect when the Transformer was instantiated and any modifications made to the Transformer instance.

An empty Source is represented as an empty document as constructed by DocumentBuilder.newDocument(). The result of transforming an empty Source depends on the transformation behavior; it is not always an empty Result.

Parameters
xmlSource Source: The XML input to transform.

outputTarget Result: The Result of transforming the xmlSource.

Throws
TransformerException If an unrecoverable error occurs during the course of the transformation.