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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

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 * particular file as subject to the "Classpath" exception as provided

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 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

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 *

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package javax.xml.transform;

/**

 * <p>A TransformerFactory instance can be used to create

 * {@link javax.xml.transform.Transformer} and

 * {@link javax.xml.transform.Templates} objects.</p>

 *

 * <p>The system property that determines which Factory implementation

 * to create is named <code>"javax.xml.transform.TransformerFactory"</code>.

 * This property names a concrete subclass of the

 * <code>TransformerFactory</code> abstract class. If the property is not

 * defined, a platform default is be used.</p>

 *

 * @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>

 * @author <a href="mailto:Neeraj.Bajaj@sun.com">Neeraj Bajaj</a>

 *

 * @since 1.5

 */

public abstract class TransformerFactory {

    /**

     * Default constructor is protected on purpose.

     */

    protected TransformerFactory() { }

    /**

     * <p>Obtain a new instance of a <code>TransformerFactory</code>.

     * This static method creates a new factory instance

     * This method uses the following ordered lookup procedure to determine

     * the <code>TransformerFactory</code> implementation class to

     * load:</p>

     * <ul>

     * <li>

     * Use the <code>javax.xml.transform.TransformerFactory</code> system

     * property.

     * </li>

     * <li>

     * Use the properties file "lib/jaxp.properties" in the JRE directory.

     * This configuration file is in standard <code>java.util.Properties

     * </code> format and contains the fully qualified name of the

     * implementation class with the key being the system property defined

     * above.

     *

     * The jaxp.properties file is read only once by the JAXP implementation

     * and it's values are then cached for future use.  If the file does not exist

     * when the first attempt is made to read from it, no further attempts are

     * made to check for its existence.  It is not possible to change the value

     * of any property in jaxp.properties after it has been read for the first time.

     * </li>

     * <li>

     * Use the Services API (as detailed in the JAR specification), if

     * available, to determine the classname. The Services API will look

     * for a classname in the file

     * <code>META-INF/services/javax.xml.transform.TransformerFactory</code>

     * in jars available to the runtime.

     * </li>

     * <li>

     * Platform default <code>TransformerFactory</code> instance.

     * </li>

     * </ul>

     *

     * <p>Once an application has obtained a reference to a <code>

     * TransformerFactory</code> it can use the factory to configure

     * and obtain transformer instances.</p>

     *

     * @return new TransformerFactory instance, never null.

     *

     * @throws TransformerFactoryConfigurationError Thrown if the implementation

     *    is not available or cannot be instantiated.

     */

    public static TransformerFactory newInstance()

        throws TransformerFactoryConfigurationError {

        try {

            return (TransformerFactory) FactoryFinder.find(

            /* The default property name according to the JAXP spec */

            "javax.xml.transform.TransformerFactory",

            /* The fallback implementation class name, XSLTC */

            "com.sun.org.apache.xalan.internal.xsltc.trax.TransformerFactoryImpl");

        } catch (FactoryFinder.ConfigurationError e) {

            throw new TransformerFactoryConfigurationError(

                e.getException(),

                e.getMessage());

        }

    }

    /**

     * <p>Obtain a new instance of a <code>TransformerFactory</code> from factory class name.

     * This function is useful when there are multiple providers in the classpath.

     * It gives more control to the application as it can specify which provider

     * should be loaded.</p>

     *

     * <p>Once an application has obtained a reference to a <code>

     * TransformerFactory</code> it can use the factory to configure

     * and obtain transformer instances.</p>

     *

     * <h2>Tip for Trouble-shooting</h2>

     * <p>Setting the <code>jaxp.debug</code> system property will cause

     * this method to print a lot of debug messages

     * to <code>System.err</code> about what it is doing and where it is looking at.</p>

     *

     * <p> If you have problems try:</p>

     * <pre>

     * java -Djaxp.debug=1 YourProgram ....

     * </pre>

     *

     * @param factoryClassName fully qualified factory class name that provides implementation of <code>javax.xml.transform.TransformerFactory</code>.

     *

     * @param classLoader <code>ClassLoader</code> used to load the factory class. If <code>null</code>

     *                     current <code>Thread</code>'s context classLoader is used to load the factory class.

     *

     * @return new TransformerFactory instance, never null.

     *

     * @throws TransformerFactoryConfigurationError

     *                    if <code>factoryClassName</code> is <code>null</code>, or

     *                   the factory class cannot be loaded, instantiated.

     *

     * @see #newInstance()

     *

     * @since 1.6

     */

    public static TransformerFactory newInstance(String factoryClassName, ClassLoader classLoader)

        throws TransformerFactoryConfigurationError{

        try {

            //do not fallback if given classloader can't find the class, throw exception

            return (TransformerFactory) FactoryFinder.newInstance(factoryClassName, classLoader, false);

        } catch (FactoryFinder.ConfigurationError e) {

            throw new TransformerFactoryConfigurationError(

                e.getException(),

                e.getMessage());

        }

    }

    /**

     * <p>Process the <code>Source</code> into a <code>Transformer</code>

     * <code>Object</code>.  The <code>Source</code> is an XSLT document that

     * conforms to <a href="http://www.w3.org/TR/xslt">

     * XSL Transformations (XSLT) Version 1.0</a>.  Care must

     * be taken not to use this <code>Transformer</code> in multiple

     * <code>Thread</code>s running concurrently.

     * Different <code>TransformerFactories</code> can be used concurrently by

     * different <code>Thread</code>s.</p>

     *

     * @param source <code>Source </code> of XSLT document used to create

     *   <code>Transformer</code>.

     *   Examples of XML <code>Source</code>s include

     *   {@link javax.xml.transform.dom.DOMSource DOMSource},

     *   {@link javax.xml.transform.sax.SAXSource SAXSource}, and

     *   {@link javax.xml.transform.stream.StreamSource StreamSource}.

     *

     * @return A <code>Transformer</code> object that may be used to perform

     *   a transformation in a single <code>Thread</code>, never

     *   <code>null</code>.

     *

     * @throws TransformerConfigurationException Thrown if there are errors when

     *    parsing the <code>Source</code> or it is not possible to create a

     *   <code>Transformer</code> instance.

     *

     * @see <a href="http://www.w3.org/TR/xslt">

     *   XSL Transformations (XSLT) Version 1.0</a>

     */

    public abstract Transformer newTransformer(Source source)

        throws TransformerConfigurationException;

    /**

     * <p>Create a new <code>Transformer</code> that performs a copy

     * of the <code>Source</code> to the <code>Result</code>.

     * i.e. the "<em>identity transform</em>".</p>

     *

     * @return A Transformer object that may be used to perform a transformation

     * in a single thread, never null.

     *

     * @throws TransformerConfigurationException When it is not

     *   possible to create a <code>Transformer</code> instance.

     */

    public abstract Transformer newTransformer()

        throws TransformerConfigurationException;

    /**

     * Process the Source into a Templates object, which is a

     * a compiled representation of the source. This Templates object

     * may then be used concurrently across multiple threads.  Creating

     * a Templates object allows the TransformerFactory to do detailed

     * performance optimization of transformation instructions, without

     * penalizing runtime transformation.

     *

     * @param source An object that holds a URL, input stream, etc.

     *

     * @return A Templates object capable of being used for transformation

     *   purposes, never <code>null</code>.

     *

     * @throws TransformerConfigurationException When parsing to

     *   construct the Templates object fails.

     */

    public abstract Templates newTemplates(Source source)

        throws TransformerConfigurationException;

    /**

     * <p>Get the stylesheet specification(s) associated with the

     * XML <code>Source</code> document via the

     * <a href="http://www.w3.org/TR/xml-stylesheet/">

     * xml-stylesheet processing instruction</a> that match the given criteria.

     * Note that it is possible to return several stylesheets, in which case

     * they are applied as if they were a list of imports or cascades in a

     * single stylesheet.</p>

     *

     * @param source The XML source document.

     * @param media The media attribute to be matched.  May be null, in which

     *      case the prefered templates will be used (i.e. alternate = no).

     * @param title The value of the title attribute to match.  May be null.

     * @param charset The value of the charset attribute to match.  May be null.

     *

     * @return A <code>Source</code> <code>Object</code> suitable for passing

     *   to the <code>TransformerFactory</code>.

     *

     * @throws TransformerConfigurationException An <code>Exception</code>

     *   is thrown if an error occurings during parsing of the

     *   <code>source</code>.

     *

     * @see <a href="http://www.w3.org/TR/xml-stylesheet/">

     *   Associating Style Sheets with XML documents Version 1.0</a>

     */

    public abstract Source getAssociatedStylesheet(

        Source source,

        String media,

        String title,

        String charset)

        throws TransformerConfigurationException;

    /**

     * Set an object that is used by default during the transformation

     * to resolve URIs used in document(), xsl:import, or xsl:include.

     *

     * @param resolver An object that implements the URIResolver interface,

     * or null.

     */

    public abstract void setURIResolver(URIResolver resolver);

    /**

     * Get the object that is used by default during the transformation

     * to resolve URIs used in document(), xsl:import, or xsl:include.

     *

     * @return The URIResolver that was set with setURIResolver.

     */

    public abstract URIResolver getURIResolver();

    //======= CONFIGURATION METHODS =======

        /**

         * <p>Set a feature for this <code>TransformerFactory</code> and <code>Transformer</code>s

         * or <code>Template</code>s created by this factory.</p>

         *

         * <p>

         * Feature names are fully qualified {@link java.net.URI}s.

         * Implementations may define their own features.

         * An {@link TransformerConfigurationException} is thrown if this <code>TransformerFactory</code> or the

         * <code>Transformer</code>s or <code>Template</code>s it creates cannot support the feature.

         * It is possible for an <code>TransformerFactory</code> to expose a feature value but be unable to change its state.

         * </p>

         *

         * <p>All implementations are required to support the {@link javax.xml.XMLConstants#FEATURE_SECURE_PROCESSING} feature.

         * When the feature is:</p>

         * <ul>

         *   <li>

         *     <code>true</code>: the implementation will limit XML processing to conform to implementation limits

         *     and behave in a secure fashion as defined by the implementation.

         *     Examples include resolving user defined style sheets and functions.

         *     If XML processing is limited for security reasons, it will be reported via a call to the registered

         *     {@link ErrorListener#fatalError(TransformerException exception)}.

         *     See {@link  #setErrorListener(ErrorListener listener)}.

         *   </li>

         *   <li>

         *     <code>false</code>: the implementation will processing XML according to the XML specifications without

         *     regard to possible implementation limits.

         *   </li>

         * </ul>

         *

         * @param name Feature name.

         * @param value Is feature state <code>true</code> or <code>false</code>.

         *

         * @throws TransformerConfigurationException if this <code>TransformerFactory</code>

         *   or the <code>Transformer</code>s or <code>Template</code>s it creates cannot support this feature.

     * @throws NullPointerException If the <code>name</code> parameter is null.

         */

        public abstract void setFeature(String name, boolean value)

                throws TransformerConfigurationException;

    /**

     * Look up the value of a feature.

     *

         * <p>

         * Feature names are fully qualified {@link java.net.URI}s.

         * Implementations may define their own features.

         * <code>false</code> is returned if this <code>TransformerFactory</code> or the

         * <code>Transformer</code>s or <code>Template</code>s it creates cannot support the feature.

         * It is possible for an <code>TransformerFactory</code> to expose a feature value but be unable to change its state.

         * </p>

         *

         * @param name Feature name.

         *

     * @return The current state of the feature, <code>true</code> or <code>false</code>.

     *

     * @throws NullPointerException If the <code>name</code> parameter is null.

     */

    public abstract boolean getFeature(String name);

    /**

     * Allows the user to set specific attributes on the underlying

     * implementation.  An attribute in this context is defined to

     * be an option that the implementation provides.

     * An <code>IllegalArgumentException</code> is thrown if the underlying

     * implementation doesn't recognize the attribute.

     *

     * @param name The name of the attribute.

     * @param value The value of the attribute.

     *

     * @throws IllegalArgumentException When implementation does not

     *   recognize the attribute.

     */

    public abstract void setAttribute(String name, Object value);

    /**

     * Allows the user to retrieve specific attributes on the underlying

     * implementation.

     * An <code>IllegalArgumentException</code> is thrown if the underlying

     * implementation doesn't recognize the attribute.

     *

     * @param name The name of the attribute.

     *

     * @return value The value of the attribute.

     *

     * @throws IllegalArgumentException When implementation does not

     *   recognize the attribute.

     */

    public abstract Object getAttribute(String name);

    /**

     * Set the error event listener for the TransformerFactory, which

     * is used for the processing of transformation instructions,

     * and not for the transformation itself.

     * An <code>IllegalArgumentException</code> is thrown if the

     * <code>ErrorListener</code> listener is <code>null</code>.

     *

     * @param listener The new error listener.

     *

     * @throws IllegalArgumentException When <code>listener</code> is

     *   <code>null</code>

     */

    public abstract void setErrorListener(ErrorListener listener);

    /**

     * Get the error event handler for the TransformerFactory.

     *

     * @return The current error handler, which should never be null.

     */

    public abstract ErrorListener getErrorListener();

}