/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ // $Id: Transformer.java 570103 2007-08-27 13:24:55Z mrglavas $ package javax.xml.transform; import java.util.Properties; /** * 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 * {@link TransformerFactory#newTransformer 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.

* * @author Jeff Suttor * @version $Revision: 570103 $, $Date: 2007-08-27 06:24:55 -0700 (Mon, 27 Aug 2007) $ */ public abstract class Transformer { /** * Default constructor is protected on purpose. */ protected Transformer() { } /** *

Reset this Transformer to its original configuration.

* *

Transformer is reset to the same state as when it was created with * {@link TransformerFactory#newTransformer()}, * {@link TransformerFactory#newTransformer(Source source)} or * {@link 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 {@link URIResolver} * or {@link ErrorListener} Objects, e.g. {@link Object#equals(Object obj)}. * It is guaranteed to have a functionally equal URIResolver * and ErrorListener.

* * @since 1.5 */ public void reset() { // implementors should override this method throw new UnsupportedOperationException( "This Transformer, \"" + this.getClass().getName() + "\", does not support the reset functionality." + " Specification \"" + this.getClass().getPackage().getSpecificationTitle() + "\"" + " version \"" + this.getClass().getPackage().getSpecificationVersion() + "\"" ); } /** *

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 {@link javax.xml.parsers.DocumentBuilder#newDocument()}. * The result of transforming an empty Source depends on * the transformation behavior; it is not always an empty * Result.

* * @param xmlSource The XML input to transform. * @param outputTarget The Result of transforming the * xmlSource. * * @throws TransformerException If an unrecoverable error occurs * during the course of the transformation. */ public abstract void transform(Source xmlSource, Result outputTarget) throws TransformerException; /** * 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.

* * @param name The name of the parameter, which may begin with a * namespace URI in curly braces ({}). * @param value 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. */ public abstract void setParameter(String name, Object value); /** * 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. * * @param name of Object to get * @return A parameter that has been set with setParameter. */ public abstract Object getParameter(String name); /** *

Set a list of parameters.

* *

Note that the list of parameters is specified as a * Properties Object which limits the parameter * values to Strings. Multiple calls to * {@link #setParameter(String name, Object value)} should be used when the * desired values are non-String Objects. * The parameter names should conform as specified in * {@link #setParameter(String name, Object value)}. * An IllegalArgumentException is thrown if any names do not * conform.

* *

New parameters in the list are added to any existing parameters. * If the name of a new parameter is equal to the name of an existing * parameter as determined by {@link java.lang.Object#equals(Object obj)}, * the existing parameter is set to the new value.

* * @param params Parameters to set. * * @throws IllegalArgumentException If any parameter names do not conform * to the naming rules. */ /** * Clear all parameters set with setParameter. */ public abstract void clearParameters(); /** * 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.

* * @param resolver An object that implements the URIResolver interface, * or null. */ public abstract void setURIResolver(URIResolver resolver); /** * Get an object that will be used to resolve URIs used in * document(). * * @return An object that implements the URIResolver interface, * or null. */ public abstract URIResolver getURIResolver(); /** * 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. * * @param oformat A set of output properties that will be * used to override any of the same properties in affect * for the transformation. * * @see javax.xml.transform.OutputKeys * @see java.util.Properties * */ public abstract void setOutputProperties(Properties oformat); /** *

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 {@link #setOutputProperty}, * {@link #setOutputProperties}, in the stylesheet, or the default * properties, while * getOutputProperties().get(String key) will only retrieve properties * that were explicitly set by {@link #setOutputProperty}, * {@link #setOutputProperties}, 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 * {@link #setOutputProperties setOutputProperties}.

* * @return A copy of the set of output properties in effect for * the next transformation. * * @see javax.xml.transform.OutputKeys * @see java.util.Properties * @see * XSL Transformations (XSLT) Version 1.0 */ public abstract Properties getOutputProperties(); /** * 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 {@link #setOutputProperties} * won't be effected by calling this method.

* * @param name A non-null String that specifies an output * property name, which may be namespace qualified. * @param value 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 javax.xml.transform.OutputKeys */ public abstract void setOutputProperty(String name, String value) throws IllegalArgumentException; /** * 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. * * @param name A non-null String that specifies an output * property name, which may be namespace qualified. * * @return The string value of the output property, or null * if no property was found. * * @throws IllegalArgumentException If the property is not supported. * * @see javax.xml.transform.OutputKeys */ public abstract String getOutputProperty(String name) throws IllegalArgumentException; /** * Set the error event listener in effect for the transformation. * * @param listener The new error listener. * @throws IllegalArgumentException if listener is null. */ public abstract void setErrorListener(ErrorListener listener) throws IllegalArgumentException; /** * Get the error event handler in effect for the transformation. * Implementations must provide a default error listener. * * @return The current error handler, which should never be null. */ public abstract ErrorListener getErrorListener(); }