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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements.  See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache License, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License.  You may obtain a copy of the License at
    8    *
    9    *     http://www.apache.org/licenses/LICENSE-2.0
   10    *
   11    * Unless required by applicable law or agreed to in writing, software
   12    * distributed under the License is distributed on an "AS IS" BASIS,
   13    * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   14    * See the License for the specific language governing permissions and
   15    * limitations under the License.
   16    */
   17   
   18   // $Id: DocumentBuilderFactory.java 884950 2009-11-27 18:46:18Z mrglavas $
   19   
   20   package javax.xml.parsers;
   21   
   22   import javax.xml.validation.Schema;
   23   
   24   /**
   25    * Defines a factory API that enables applications to obtain a
   26    * parser that produces DOM object trees from XML documents.
   27    *
   28    * @author <a href="Jeff.Suttor@Sun.com">Jeff Suttor</a>
   29    * @version $Revision: 884950 $, $Date: 2009-11-27 13:46:18 -0500 (Fri, 27 Nov 2009) $
   30    */
   31   
   32   public abstract class DocumentBuilderFactory {
   33   
   34       private boolean validating = false;
   35       private boolean namespaceAware = false;
   36       private boolean whitespace = false;
   37       private boolean expandEntityRef = true;
   38       private boolean ignoreComments = false;
   39       private boolean coalescing = false;
   40       
   41       protected DocumentBuilderFactory () {
   42       }
   43   
   44       /**
   45        * Obtain a new instance of a
   46        * <code>DocumentBuilderFactory</code>. This static method creates
   47        * a new factory instance.
   48        * This method uses the following ordered lookup procedure to determine
   49        * the <code>DocumentBuilderFactory</code> implementation class to
   50        * load:
   51        * <ul>
   52        * <li>
   53        * Use the <code>javax.xml.parsers.DocumentBuilderFactory</code> system
   54        * property.
   55        * </li>
   56        * <li>
   57        * Use the properties file "lib/jaxp.properties" in the JRE directory.
   58        * This configuration file is in standard <code>java.util.Properties
   59        * </code> format and contains the fully qualified name of the
   60        * implementation class with the key being the system property defined
   61        * above.
   62        * 
   63        * The jaxp.properties file is read only once by the JAXP implementation
   64        * and it's values are then cached for future use.  If the file does not exist
   65        * when the first attempt is made to read from it, no further attempts are
   66        * made to check for its existence.  It is not possible to change the value
   67        * of any property in jaxp.properties after it has been read for the first time.
   68        * </li>
   69        * <li>
   70        * Use the Services API (as detailed in the JAR specification), if
   71        * available, to determine the classname. The Services API will look
   72        * for a classname in the file
   73        * <code>META-INF/services/javax.xml.parsers.DocumentBuilderFactory</code>
   74        * in jars available to the runtime.
   75        * </li>
   76        * <li>
   77        * Platform default <code>DocumentBuilderFactory</code> instance.
   78        * </li>
   79        * </ul>
   80        *
   81        * Once an application has obtained a reference to a
   82        * <code>DocumentBuilderFactory</code> it can use the factory to
   83        * configure and obtain parser instances.
   84        * 
   85        * 
   86        * <h2>Tip for Trouble-shooting</h2>
   87        * <p>Setting the <code>jaxp.debug</code> system property will cause
   88        * this method to print a lot of debug messages
   89        * to <tt>System.err</tt> about what it is doing and where it is looking at.</p>
   90        * 
   91        * <p> If you have problems loading {@link DocumentBuilder}s, try:</p>
   92        * <pre>
   93        * java -Djaxp.debug=1 YourProgram ....
   94        * </pre>
   95        * 
   96        * @return New instance of a <code>DocumentBuilderFactory</code>
   97        *
   98        * @exception FactoryConfigurationError if the implementation is not
   99        * available or cannot be instantiated.
  100        */
  101       public static DocumentBuilderFactory newInstance() {
  102           try {
  103               return (DocumentBuilderFactory) FactoryFinder.find(
  104                   /* The default property name according to the JAXP spec */
  105                   "javax.xml.parsers.DocumentBuilderFactory",
  106                   /* The fallback implementation class name */
  107                   "org.apache.xerces.jaxp.DocumentBuilderFactoryImpl");
  108           } 
  109           catch (FactoryFinder.ConfigurationError e) {
  110               throw new FactoryConfigurationError(e.getException(), e.getMessage());
  111           }
  112       }
  113       
  114       /**
  115        * @return New instance of a <code>DocumentBuilderFactory</code>
  116        *
  117        * @exception FactoryConfigurationError if the implementation is not
  118        * available or cannot be instantiated.
  119        */
  120       public static DocumentBuilderFactory newInstance(String factoryClassName,
  121               ClassLoader classLoader) {
  122           if (factoryClassName == null) {
  123               throw new FactoryConfigurationError("factoryClassName cannot be null.");
  124           }
  125           if (classLoader == null) {
  126               classLoader = SecuritySupport.getContextClassLoader();
  127           }
  128           try {
  129               return (DocumentBuilderFactory) FactoryFinder.newInstance(factoryClassName, classLoader, false);
  130           }
  131           catch (FactoryFinder.ConfigurationError e) {
  132               throw new FactoryConfigurationError(e.getException(), e.getMessage());
  133           }
  134       }
  135   
  136       /**
  137        * Creates a new instance of a {@link javax.xml.parsers.DocumentBuilder}
  138        * using the currently configured parameters.
  139        *
  140        * @exception ParserConfigurationException if a DocumentBuilder
  141        * cannot be created which satisfies the configuration requested.
  142        * @return A new instance of a DocumentBuilder.
  143        */
  144       
  145       public abstract DocumentBuilder newDocumentBuilder()
  146           throws ParserConfigurationException;
  147       
  148       
  149       /**
  150        * Specifies that the parser produced by this code will
  151        * provide support for XML namespaces. By default the value of this is set
  152        * to <code>false</code>
  153        *
  154        * @param awareness true if the parser produced will provide support
  155        *                  for XML namespaces; false otherwise.
  156        */
  157       
  158       public void setNamespaceAware(boolean awareness) {
  159           this.namespaceAware = awareness;
  160       }
  161   
  162       /**
  163        * Specifies that the parser produced by this code will
  164        * validate documents as they are parsed. By default the value of this
  165        * is set to <code>false</code>.
  166        * 
  167        * <p>
  168        * Note that "the validation" here means
  169        * <a href="http://www.w3.org/TR/REC-xml#proc-types">a validating
  170        * parser</a> as defined in the XML recommendation.
  171        * In other words, it essentially just controls the DTD validation.
  172        * (except the legacy two properties defined in JAXP 1.2.
  173        * See <a href="#validationCompatibility">here</a> for more details.)
  174        * </p>
  175        * 
  176        * <p>
  177        * To use modern schema languages such as W3C XML Schema or
  178        * RELAX NG instead of DTD, you can configure your parser to be
  179        * a non-validating parser by leaving the {@link #setValidating(boolean)}
  180        * method <tt>false</tt>, then use the {@link #setSchema(Schema)}
  181        * method to associate a schema to a parser.
  182        * </p>
  183        * 
  184        * @param validating true if the parser produced will validate documents
  185        *                   as they are parsed; false otherwise.
  186        */
  187       
  188       public void setValidating(boolean validating) {
  189           this.validating = validating;
  190       }
  191   
  192       /**
  193        * Specifies that the parsers created by this  factory must eliminate
  194        * whitespace in element content (sometimes known loosely as
  195        * 'ignorable whitespace') when parsing XML documents (see XML Rec
  196        * 2.10). Note that only whitespace which is directly contained within
  197        * element content that has an element only content model (see XML
  198        * Rec 3.2.1) will be eliminated. Due to reliance on the content model
  199        * this setting requires the parser to be in validating mode. By default
  200        * the value of this is set to <code>false</code>.
  201        *
  202        * @param whitespace true if the parser created must eliminate whitespace
  203        *                   in the element content when parsing XML documents;
  204        *                   false otherwise.
  205        */
  206   
  207       public void setIgnoringElementContentWhitespace(boolean whitespace) {
  208           this.whitespace = whitespace;
  209       }
  210   
  211       /**
  212        * Specifies that the parser produced by this code will
  213        * expand entity reference nodes. By default the value of this is set to
  214        * <code>true</code>
  215        *
  216        * @param expandEntityRef true if the parser produced will expand entity
  217        *                        reference nodes; false otherwise.
  218        */
  219       
  220       public void setExpandEntityReferences(boolean expandEntityRef) {
  221           this.expandEntityRef = expandEntityRef;
  222       }
  223   
  224       /**
  225        * <p>Specifies that the parser produced by this code will
  226        * ignore comments. By default the value of this is set to <code>false
  227        * </code>.</p>
  228        * 
  229        * @param ignoreComments <code>boolean</code> value to ignore comments during processing
  230        */
  231       
  232       public void setIgnoringComments(boolean ignoreComments) {
  233           this.ignoreComments = ignoreComments;
  234       }
  235   
  236       /**
  237        * Specifies that the parser produced by this code will
  238        * convert CDATA nodes to Text nodes and append it to the
  239        * adjacent (if any) text node. By default the value of this is set to
  240        * <code>false</code>
  241        *
  242        * @param coalescing  true if the parser produced will convert CDATA nodes
  243        *                    to Text nodes and append it to the adjacent (if any)
  244        *                    text node; false otherwise.
  245        */
  246       
  247       public void setCoalescing(boolean coalescing) {
  248           this.coalescing = coalescing;
  249       }
  250   
  251       /**
  252        * Indicates whether or not the factory is configured to produce
  253        * parsers which are namespace aware.
  254        *
  255        * @return  true if the factory is configured to produce parsers which
  256        *          are namespace aware; false otherwise.
  257        */
  258       
  259       public boolean isNamespaceAware() {
  260           return namespaceAware;
  261       }
  262   
  263       /**
  264        * Indicates whether or not the factory is configured to produce
  265        * parsers which validate the XML content during parse.
  266        *
  267        * @return  true if the factory is configured to produce parsers
  268        *          which validate the XML content during parse; false otherwise.
  269        */
  270       
  271       public boolean isValidating() {
  272           return validating;
  273       }
  274   
  275       /**
  276        * Indicates whether or not the factory is configured to produce
  277        * parsers which ignore ignorable whitespace in element content.
  278        *
  279        * @return  true if the factory is configured to produce parsers
  280        *          which ignore ignorable whitespace in element content;
  281        *          false otherwise.
  282        */
  283       
  284       public boolean isIgnoringElementContentWhitespace() {
  285           return whitespace;
  286       }
  287   
  288       /**
  289        * Indicates whether or not the factory is configured to produce
  290        * parsers which expand entity reference nodes.
  291        *
  292        * @return  true if the factory is configured to produce parsers
  293        *          which expand entity reference nodes; false otherwise.
  294        */
  295       
  296       public boolean isExpandEntityReferences() {
  297           return expandEntityRef;
  298       }
  299   
  300       /**
  301        * Indicates whether or not the factory is configured to produce
  302        * parsers which ignores comments.
  303        *
  304        * @return  true if the factory is configured to produce parsers
  305        *          which ignores comments; false otherwise.
  306        */
  307       
  308       public boolean isIgnoringComments() {
  309           return ignoreComments;
  310       }
  311   
  312       /**
  313        * Indicates whether or not the factory is configured to produce
  314        * parsers which converts CDATA nodes to Text nodes and appends it to
  315        * the adjacent (if any) Text node.
  316        *
  317        * @return  true if the factory is configured to produce parsers
  318        *          which converts CDATA nodes to Text nodes and appends it to
  319        *          the adjacent (if any) Text node; false otherwise.
  320        */
  321       
  322       public boolean isCoalescing() {
  323           return coalescing;
  324       }
  325   
  326       /**
  327        * Allows the user to set specific attributes on the underlying
  328        * implementation.
  329        * @param name The name of the attribute.
  330        * @param value The value of the attribute.
  331        * @exception IllegalArgumentException thrown if the underlying
  332        * implementation doesn't recognize the attribute.
  333        */
  334       public abstract void setAttribute(String name, Object value)
  335                   throws IllegalArgumentException;
  336   
  337       /**
  338        * Allows the user to retrieve specific attributes on the underlying
  339        * implementation.
  340        * @param name The name of the attribute.
  341        * @return value The value of the attribute.
  342        * @exception IllegalArgumentException thrown if the underlying
  343        * implementation doesn't recognize the attribute.
  344        */
  345       public abstract Object getAttribute(String name)
  346                   throws IllegalArgumentException;
  347                   
  348   	/**
  349   	 * <p>Set a feature for this <code>DocumentBuilderFactory</code> and <code>DocumentBuilder</code>s created by this factory.</p>
  350   	 * 
  351   	 * <p>
  352   	 * Feature names are fully qualified {@link java.net.URI}s.
  353   	 * Implementations may define their own features.
  354   	 * An {@link ParserConfigurationException} is thrown if this <code>DocumentBuilderFactory</code> or the
  355   	 * <code>DocumentBuilder</code>s it creates cannot support the feature.
  356   	 * It is possible for an <code>DocumentBuilderFactory</code> to expose a feature value but be unable to change its state.
  357   	 * </p>
  358   	 * 
  359   	 * <p>
  360   	 * All implementations are required to support the {@link javax.xml.XMLConstants#FEATURE_SECURE_PROCESSING} feature.
  361   	 * When the feature is:</p>
  362   	 * <ul>
  363   	 *   <li>
  364   	 *     <code>true</code>: the implementation will limit XML processing to conform to implementation limits.
  365   	 *     Examples include entity expansion limits and XML Schema constructs that would consume large amounts of resources.
  366   	 *     If XML processing is limited for security reasons, it will be reported via a call to the registered
  367   	 *    {@link org.xml.sax.ErrorHandler#fatalError(SAXParseException exception)}.
  368   	 *     See {@link  DocumentBuilder#setErrorHandler(org.xml.sax.ErrorHandler errorHandler)}.
  369   	 *   </li>
  370   	 *   <li>
  371   	 *     <code>false</code>: the implementation will processing XML according to the XML specifications without
  372   	 *     regard to possible implementation limits.
  373   	 *   </li>
  374   	 * </ul>
  375   	 * 
  376   	 * @param name Feature name.
  377   	 * @param value Is feature state <code>true</code> or <code>false</code>.
  378   	 *  
  379   	 * @throws ParserConfigurationException if this <code>DocumentBuilderFactory</code> or the <code>DocumentBuilder</code>s
  380   	 *   it creates cannot support this feature.
  381        * @throws NullPointerException If the <code>name</code> parameter is null.
  382   	 */
  383   	public abstract void setFeature(String name, boolean value)
  384   		throws ParserConfigurationException;
  385   
  386   	/**
  387   	 * <p>Get the state of the named feature.</p>
  388   	 * 
  389   	 * <p>
  390   	 * Feature names are fully qualified {@link java.net.URI}s.
  391   	 * Implementations may define their own features.
  392   	 * An {@link ParserConfigurationException} is thrown if this <code>DocumentBuilderFactory</code> or the
  393   	 * <code>DocumentBuilder</code>s it creates cannot support the feature.
  394   	 * It is possible for an <code>DocumentBuilderFactory</code> to expose a feature value but be unable to change its state.
  395   	 * </p>
  396   	 * 
  397   	 * @param name Feature name.
  398   	 * 
  399   	 * @return State of the named feature.
  400   	 * 
  401   	 * @throws ParserConfigurationException if this <code>DocumentBuilderFactory</code>
  402   	 *   or the <code>DocumentBuilder</code>s it creates cannot support this feature.
  403   	 */
  404   	public abstract boolean getFeature(String name)
  405   		throws ParserConfigurationException;
  406       
  407       /**
  408        * Gets the {@link Schema} object specified through
  409        * the {@link #setSchema(Schema schema)} method.
  410        * 
  411        * 
  412        * @throws UnsupportedOperationException
  413        *      For backward compatibility, when implementations for
  414        *      earlier versions of JAXP is used, this exception will be
  415        *      thrown.
  416        * 
  417        * @return
  418        *      the {@link Schema} object that was last set through
  419        *      the {@link #setSchema(Schema)} method, or null
  420        *      if the method was not invoked since a {@link DocumentBuilderFactory}
  421        *      is created.
  422        * 
  423        * @since 1.5
  424        */
  425       public Schema getSchema() {
  426           throw new UnsupportedOperationException(
  427               "This parser does not support specification \""
  428               + this.getClass().getPackage().getSpecificationTitle()
  429               + "\" version \""
  430               + this.getClass().getPackage().getSpecificationVersion()
  431               + "\""
  432               );
  433   
  434       }
  435       
  436       /**
  437        * <p>Set the {@link Schema} to be used by parsers created
  438        * from this factory.
  439        * 
  440        * <p>
  441        * When a {@link Schema} is non-null, a parser will use a validator
  442        * created from it to validate documents before it passes information
  443        * down to the application.
  444        * 
  445        * <p>When errors are found by the validator, the parser is responsible
  446        * to report them to the user-specified {@link org.xml.sax.ErrorHandler}
  447        * (or if the error handler is not set, ignore them or throw them), just
  448        * like any other errors found by the parser itself.
  449        * In other words, if the user-specified {@link org.xml.sax.ErrorHandler}
  450        * is set, it must receive those errors, and if not, they must be
  451        * treated according to the implementation specific
  452        * default error handling rules.
  453        * 
  454        * <p>
  455        * A validator may modify the outcome of a parse (for example by
  456        * adding default values that were missing in documents), and a parser
  457        * is responsible to make sure that the application will receive
  458        * modified DOM trees.  
  459        * 
  460        * <p>
  461        * Initially, null is set as the {@link Schema}. 
  462        * 
  463        * <p>
  464        * This processing will take effect even if
  465        * the {@link #isValidating()} method returns <tt>false</tt>.
  466        * 
  467        * <p>It is an error to use
  468        * the <code>http://java.sun.com/xml/jaxp/properties/schemaSource</code>
  469        * property and/or the <code>http://java.sun.com/xml/jaxp/properties/schemaLanguage</code>
  470        * property in conjunction with a {@link Schema} object.
  471        * Such configuration will cause a {@link ParserConfigurationException}
  472        * exception when the {@link #newDocumentBuilder()} is invoked.</p>
  473        *
  474        *  
  475        * <h4>Note for implementors</h4>
  476        * <p>
  477        * A parser must be able to work with any {@link Schema}
  478        * implementation. However, parsers and schemas are allowed
  479        * to use implementation-specific custom mechanisms
  480        * as long as they yield the result described in the specification.
  481        * 
  482        * @param schema <code>Schema</code> to use or <code>null</code> to remove a schema.
  483        * 
  484        * @throws UnsupportedOperationException
  485        *      For backward compatibility, when implementations for
  486        *      earlier versions of JAXP is used, this exception will be
  487        *      thrown.
  488        * 
  489        * @since 1.5
  490        */
  491       public void setSchema(Schema schema) {
  492           throw new UnsupportedOperationException(
  493               "This parser does not support specification \""
  494               + this.getClass().getPackage().getSpecificationTitle()
  495               + "\" version \""
  496               + this.getClass().getPackage().getSpecificationVersion()
  497               + "\""
  498               );
  499       }
  500       
  501       /**
  502        * <p>Set state of XInclude processing.</p>
  503        * 
  504        * <p>If XInclude markup is found in the document instance, should it be
  505        * processed as specified in <a href="http://www.w3.org/TR/xinclude/">
  506        * XML Inclusions (XInclude) Version 1.0</a>.</p>
  507        * 
  508        * <p>XInclude processing defaults to <code>false</code>.</p>
  509        * 
  510        * @param state Set XInclude processing to <code>true</code> or
  511        *   <code>false</code>
  512        * 
  513        * @throws UnsupportedOperationException
  514        *      For backward compatibility, when implementations for
  515        *      earlier versions of JAXP is used, this exception will be
  516        *      thrown.
  517        * 
  518        * @since 1.5
  519        */
  520       public void setXIncludeAware(final boolean state) {
  521           throw new UnsupportedOperationException(
  522               "This parser does not support specification \""
  523               + this.getClass().getPackage().getSpecificationTitle()
  524               + "\" version \""
  525               + this.getClass().getPackage().getSpecificationVersion()
  526               + "\""
  527               );
  528       }
  529   
  530       /**
  531        * <p>Get state of XInclude processing.</p>
  532        * 
  533        * @return current state of XInclude processing
  534        * 
  535        * @throws UnsupportedOperationException
  536        *      For backward compatibility, when implementations for
  537        *      earlier versions of JAXP is used, this exception will be
  538        *      thrown.
  539        * 
  540        * @since 1.5
  541        */
  542       public boolean isXIncludeAware() {
  543           throw new UnsupportedOperationException(
  544               "This parser does not support specification \""
  545               + this.getClass().getPackage().getSpecificationTitle()
  546               + "\" version \""
  547               + this.getClass().getPackage().getSpecificationVersion()
  548               + "\""
  549               );
  550       }
  551   }

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