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package javax.xml.parsers;

import javax.xml.validation.Schema;

/**

 * Defines a factory API that enables applications to obtain a

 * parser that produces DOM object trees from XML documents.

 *

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

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

 *

 * @version $Revision: 1.9 $, $Date: 2010/05/25 16:19:44 $

 */

public abstract class DocumentBuilderFactory {

    private boolean validating = false;

    private boolean namespaceAware = false;

    private boolean whitespace = false;

    private boolean expandEntityRef = true;

    private boolean ignoreComments = false;

    private boolean coalescing = false;

    /**

     * <p>Protected constructor to prevent instantiation.

     * Use {@link #newInstance()}.</p>

     */

    protected DocumentBuilderFactory () {

    }

    /**

     * Obtain a new instance of a

     * <code>DocumentBuilderFactory</code>. This static method creates

     * a new factory instance.

     * This method uses the following ordered lookup procedure to determine

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

     * load:

     * <ul>

     * <li>

     * Use the <code>javax.xml.parsers.DocumentBuilderFactory</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>

     * Uses the service-provider loading facilities, defined by the

     * {@link java.util.ServiceLoader} class, to attempt to locate and load an

     * implementation of the service using the {@linkplain

     * java.util.ServiceLoader#load(java.lang.Class) default loading mechanism}:

     * the service-provider loading facility will use the {@linkplain

     * java.lang.Thread#getContextClassLoader() current thread's context class loader}

     * to attempt to load the service. If the context class

     * loader is null, the {@linkplain

     * ClassLoader#getSystemClassLoader() system class loader} will be used.

     * </li>

     * <li>

     * Otherwise, the system-default implementation is returned.

     * </li>

     * </ul>

     *

     * Once an application has obtained a reference to a

     * <code>DocumentBuilderFactory</code> it can use the factory to

     * configure and obtain parser instances.

     *

     *

     * <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 loading {@link DocumentBuilder}s, try:</p>

     * <pre>

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

     * </pre>

     *

     * @return New instance of a <code>DocumentBuilderFactory</code>

     *

     * @throws FactoryConfigurationError in case of {@linkplain

     * java.util.ServiceConfigurationError service configuration error} or if

     * the implementation is not available or cannot be instantiated.

     */

    public static DocumentBuilderFactory newInstance() {

        return FactoryFinder.find(

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

                DocumentBuilderFactory.class, // "javax.xml.parsers.DocumentBuilderFactory"

                /* The fallback implementation class name */

                "com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderFactoryImpl");

    }

    /**

     * <p>Obtain a new instance of a <code>DocumentBuilderFactory</code> from 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>DocumentBuilderFactory</code>

     * it can use the factory to configure and obtain parser 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.parsers.DocumentBuilderFactory</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 instance of a <code>DocumentBuilderFactory</code>

     *

     * @throws FactoryConfigurationError if <code>factoryClassName</code> is <code>null</code>, or

     *                                   the factory class cannot be loaded, instantiated.

     *

     * @see #newInstance()

     *

     * @since 1.6

     */

    public static DocumentBuilderFactory newInstance(String factoryClassName, ClassLoader classLoader){

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

            return FactoryFinder.newInstance(DocumentBuilderFactory.class,

                        factoryClassName, classLoader, false);

    }

    /**

     * Creates a new instance of a {@link javax.xml.parsers.DocumentBuilder}

     * using the currently configured parameters.

     *

     * @return A new instance of a DocumentBuilder.

     *

     * @throws ParserConfigurationException if a DocumentBuilder

     *   cannot be created which satisfies the configuration requested.

     */

    public abstract DocumentBuilder newDocumentBuilder()

        throws ParserConfigurationException;

    /**

     * Specifies that the parser produced by this code will

     * provide support for XML namespaces. By default the value of this is set

     * to <code>false</code>

     *

     * @param awareness true if the parser produced will provide support

     *                  for XML namespaces; false otherwise.

     */

    public void setNamespaceAware(boolean awareness) {

        this.namespaceAware = awareness;

    }

    /**

     * Specifies that the parser produced by this code will

     * validate documents as they are parsed. By default the value of this

     * is set to <code>false</code>.

     *

     * <p>

     * Note that "the validation" here means

     * <a href="http://www.w3.org/TR/REC-xml#proc-types">a validating

     * parser</a> as defined in the XML recommendation.

     * In other words, it essentially just controls the DTD validation.

     * (except the legacy two properties defined in JAXP 1.2.)

     * </p>

     *

     * <p>

     * To use modern schema languages such as W3C XML Schema or

     * RELAX NG instead of DTD, you can configure your parser to be

     * a non-validating parser by leaving the {@link #setValidating(boolean)}

     * method <code>false</code>, then use the {@link #setSchema(Schema)}

     * method to associate a schema to a parser.

     * </p>

     *

     * @param validating true if the parser produced will validate documents

     *                   as they are parsed; false otherwise.

     */

    public void setValidating(boolean validating) {

        this.validating = validating;

    }

    /**

     * Specifies that the parsers created by this  factory must eliminate

     * whitespace in element content (sometimes known loosely as

     * 'ignorable whitespace') when parsing XML documents (see XML Rec

     * 2.10). Note that only whitespace which is directly contained within

     * element content that has an element only content model (see XML

     * Rec 3.2.1) will be eliminated. Due to reliance on the content model

     * this setting requires the parser to be in validating mode. By default

     * the value of this is set to <code>false</code>.

     *

     * @param whitespace true if the parser created must eliminate whitespace

     *                   in the element content when parsing XML documents;

     *                   false otherwise.

     */

    public void setIgnoringElementContentWhitespace(boolean whitespace) {

        this.whitespace = whitespace;

    }

    /**

     * Specifies that the parser produced by this code will

     * expand entity reference nodes. By default the value of this is set to

     * <code>true</code>

     *

     * @param expandEntityRef true if the parser produced will expand entity

     *                        reference nodes; false otherwise.

     */

    public void setExpandEntityReferences(boolean expandEntityRef) {

        this.expandEntityRef = expandEntityRef;

    }

    /**

     * <p>Specifies that the parser produced by this code will

     * ignore comments. By default the value of this is set to <code>false

     * </code>.</p>

     *

     * @param ignoreComments <code>boolean</code> value to ignore comments during processing

     */

    public void setIgnoringComments(boolean ignoreComments) {

        this.ignoreComments = ignoreComments;

    }

    /**

     * Specifies that the parser produced by this code will

     * convert CDATA nodes to Text nodes and append it to the

     * adjacent (if any) text node. By default the value of this is set to

     * <code>false</code>

     *

     * @param coalescing  true if the parser produced will convert CDATA nodes

     *                    to Text nodes and append it to the adjacent (if any)

     *                    text node; false otherwise.

     */

    public void setCoalescing(boolean coalescing) {

        this.coalescing = coalescing;

    }

    /**

     * Indicates whether or not the factory is configured to produce

     * parsers which are namespace aware.

     *

     * @return  true if the factory is configured to produce parsers which

     *          are namespace aware; false otherwise.

     */

    public boolean isNamespaceAware() {

        return namespaceAware;

    }

    /**

     * Indicates whether or not the factory is configured to produce

     * parsers which validate the XML content during parse.

     *

     * @return  true if the factory is configured to produce parsers

     *          which validate the XML content during parse; false otherwise.

     */

    public boolean isValidating() {

        return validating;

    }

    /**

     * Indicates whether or not the factory is configured to produce

     * parsers which ignore ignorable whitespace in element content.

     *

     * @return  true if the factory is configured to produce parsers

     *          which ignore ignorable whitespace in element content;

     *          false otherwise.

     */

    public boolean isIgnoringElementContentWhitespace() {

        return whitespace;

    }

    /**

     * Indicates whether or not the factory is configured to produce

     * parsers which expand entity reference nodes.

     *

     * @return  true if the factory is configured to produce parsers

     *          which expand entity reference nodes; false otherwise.

     */

    public boolean isExpandEntityReferences() {

        return expandEntityRef;

    }

    /**

     * Indicates whether or not the factory is configured to produce

     * parsers which ignores comments.

     *

     * @return  true if the factory is configured to produce parsers

     *          which ignores comments; false otherwise.

     */

    public boolean isIgnoringComments() {

        return ignoreComments;

    }

    /**

     * Indicates whether or not the factory is configured to produce

     * parsers which converts CDATA nodes to Text nodes and appends it to

     * the adjacent (if any) Text node.

     *

     * @return  true if the factory is configured to produce parsers

     *          which converts CDATA nodes to Text nodes and appends it to

     *          the adjacent (if any) Text node; false otherwise.

     */

    public boolean isCoalescing() {

        return coalescing;

    }

    /**

     * Allows the user to set specific attributes on the underlying

     * implementation.

     * <p>

     * All implementations that implement JAXP 1.5 or newer are required to

     * support the {@link javax.xml.XMLConstants#ACCESS_EXTERNAL_DTD} and

     * {@link javax.xml.XMLConstants#ACCESS_EXTERNAL_SCHEMA} properties.

     * </p>

     * <ul>

     *   <li>

     *      <p>

     *      Setting the {@link javax.xml.XMLConstants#ACCESS_EXTERNAL_DTD} property

     *      restricts the access to external DTDs, external Entity References to the

     *      protocols specified by the property.

     *      If access is denied during parsing due to the restriction of this property,

     *      {@link org.xml.sax.SAXException} will be thrown by the parse methods defined by

     *      {@link javax.xml.parsers.DocumentBuilder}.

     *      </p>

     *      <p>

     *      Setting the {@link javax.xml.XMLConstants#ACCESS_EXTERNAL_SCHEMA} property

     *      restricts the access to external Schema set by the schemaLocation attribute to

     *      the protocols specified by the property.  If access is denied during parsing

     *      due to the restriction of this property, {@link org.xml.sax.SAXException}

     *      will be thrown by the parse methods defined by

     *      {@link javax.xml.parsers.DocumentBuilder}.

     *      </p>

     *   </li>

     * </ul>

     *

     * @param name The name of the attribute.

     * @param value The value of the attribute.

     *

     * @throws IllegalArgumentException thrown if the underlying

     *   implementation doesn't recognize the attribute.

     */

    public abstract void setAttribute(String name, Object value)

                throws IllegalArgumentException;

    /**

     * Allows the user to retrieve specific attributes on the underlying

     * implementation.

     *

     * @param name The name of the attribute.

     *

     * @return value The value of the attribute.

     *

     * @throws IllegalArgumentException thrown if the underlying

     *   implementation doesn't recognize the attribute.

     */

    public abstract Object getAttribute(String name)

                throws IllegalArgumentException;

    /**

     * <p>Set a feature for this <code>DocumentBuilderFactory</code> and <code>DocumentBuilder</code>s created by this factory.</p>

     *

     * <p>

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

     * Implementations may define their own features.

     * A {@link ParserConfigurationException} is thrown if this <code>DocumentBuilderFactory</code> or the

     * <code>DocumentBuilder</code>s it creates cannot support the feature.

     * It is possible for a <code>DocumentBuilderFactory</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.

     *     Examples include entity expansion limits and XML Schema constructs that would consume large amounts of resources.

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

     *    {@link org.xml.sax.ErrorHandler#fatalError(SAXParseException exception)}.

     *     See {@link  DocumentBuilder#setErrorHandler(org.xml.sax.ErrorHandler errorHandler)}.

     *   </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 ParserConfigurationException if this <code>DocumentBuilderFactory</code> or the <code>DocumentBuilder</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 ParserConfigurationException;

    /**

     * <p>Get the state of the named feature.</p>

     *

     * <p>

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

     * Implementations may define their own features.

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

     * <code>DocumentBuilder</code>s it creates cannot support the feature.

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

     * </p>

     *

     * @param name Feature name.

     *

     * @return State of the named feature.

     *

     * @throws ParserConfigurationException if this <code>DocumentBuilderFactory</code>

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

     */

    public abstract boolean getFeature(String name)

            throws ParserConfigurationException;

    /**

     * Gets the {@link Schema} object specified through

     * the {@link #setSchema(Schema schema)} method.

     *

     * @return

     *      the {@link Schema} object that was last set through

     *      the {@link #setSchema(Schema)} method, or null

     *      if the method was not invoked since a {@link DocumentBuilderFactory}

     *      is created.

     *

     * @throws UnsupportedOperationException When implementation does not

     *   override this method.

     *

     * @since 1.5

     */

    public Schema getSchema() {

        throw new UnsupportedOperationException(

            "This parser does not support specification \""

            + this.getClass().getPackage().getSpecificationTitle()

            + "\" version \""

            + this.getClass().getPackage().getSpecificationVersion()

            + "\""

            );

    }

    /**

     * <p>Set the {@link Schema} to be used by parsers created

     * from this factory.

     *

     * <p>

     * When a {@link Schema} is non-null, a parser will use a validator

     * created from it to validate documents before it passes information

     * down to the application.

     *

     * <p>When errors are found by the validator, the parser is responsible

     * to report them to the user-specified {@link org.xml.sax.ErrorHandler}

     * (or if the error handler is not set, ignore them or throw them), just

     * like any other errors found by the parser itself.

     * In other words, if the user-specified {@link org.xml.sax.ErrorHandler}

     * is set, it must receive those errors, and if not, they must be

     * treated according to the implementation specific

     * default error handling rules.

     *

     * <p>

     * A validator may modify the outcome of a parse (for example by

     * adding default values that were missing in documents), and a parser

     * is responsible to make sure that the application will receive

     * modified DOM trees.

     *