documentfactory.java

Java的面向对象数据库系统的源代码

/*
 * Copyright 2001 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * This software is open source.
 * See the bottom of this file for the licence.
 *
 * $Id: DocumentFactory.java,v 1.3 2003/11/02 17:55:20 per_nyfelt Exp $
 */

package org.dom4j;

import org.dom4j.rule.Pattern;
import org.dom4j.tree.*;
import org.dom4j.xpath.DefaultXPath;
import org.dom4j.xpath.XPathPattern;
import org.jaxen.VariableContext;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.util.List;
import java.util.Map;

/** <p><code>DocumentFactory</code> is a collection of factory methods to allow
  * easy custom building of DOM4J trees. The default tree that is built uses
  * a doubly linked tree. </p>
  *
  * <p>The tree built allows full XPath expressions from anywhere on the
  * tree.</p>
  *
  * @author <a href="mailto:[e-mail]">James Strachan</a>
  * @version $Revision: 1.3 $
  */
public class DocumentFactory implements Serializable, NodeFactory, XPathFactory {

    /** The Singleton instance */
    //private static transient DocumentFactory singleton;
    private final static ThreadLocal singlePerThread=new ThreadLocal();
    private static String documentFactoryClassName=null;

    protected transient QNameCache cache;

    /** Default namespace prefix -> URI mappings for XPath expressions to use */
    private Map xpathNamespaceURIs;

    static {
        try {
            documentFactoryClassName = System.getProperty(
                "org.dom4j.factory",
                "org.dom4j.DocumentFactory"
            );
        }
        catch (Exception e) {
            documentFactoryClassName = "org.dom4j.DocumentFactory";
        }
        getInstance();  //create first one
    }

    /** <p>Access to singleton implementation of DocumentFactory which
      * is used if no DocumentFactory is specified when building using the
      * standard builders.</p>
      *
      * @return the default singleon instance
      */
    public static DocumentFactory getInstance() {
        DocumentFactory fact = (DocumentFactory)singlePerThread.get();
        if (fact==null) {
          fact=createSingleton( documentFactoryClassName ); //create first instance
          singlePerThread.set(fact);
        }
        return fact;
    }

    public DocumentFactory() {
        init();
    }


    // Factory methods

    public Document createDocument() {
        DefaultDocument answer = new DefaultDocument();
        answer.setDocumentFactory( this );
        return answer;
    }

    public Document createDocument(Element rootElement) {
        Document answer = createDocument();
        answer.setRootElement(rootElement);
        return answer;
    }

    public DocumentType createDocType(String name, String publicId, String systemId) {
        return new DefaultDocumentType( name, publicId, systemId );
    }

    public Element createElement(QName qname) {
        return new DefaultElement(qname);
    }

    public Element createElement(String name) {
        return createElement(createQName(name));
    }

    public Element createElement(String qualifiedName, String namespaceURI) {
        return createElement(createQName(qualifiedName, namespaceURI));
    }

    public Attribute createAttribute(Element owner, QName qname, String value) {
        return new DefaultAttribute(qname, value);
    }

    public Attribute createAttribute(Element owner, String name, String value) {
        return createAttribute(owner, createQName(name), value);
    }

    public CDATA createCDATA(String text) {
        return new DefaultCDATA(text);
    }

    public Comment createComment(String text) {
        return new DefaultComment(text);
    }

    public Text createText(String text) {
        if ( text == null ) {
            throw new IllegalArgumentException( "Adding text to an XML document must not be null" );
        }
        return new DefaultText(text);
    }


    public Entity createEntity(String name, String text) {
        return new DefaultEntity(name, text);
    }

    public Namespace createNamespace(String prefix, String uri) {
        return AbstractNamespace.get(prefix, uri);
    }

    public Namespace getNamespace(String uri) {
        return AbstractNamespace.get(uri);
    }

    public Namespace getXmlNameSpace() {
        return AbstractNamespace.XML_NAMESPACE;
    }

    public Namespace getNoNamespace() {
        return AbstractNamespace.NO_NAMESPACE;
    }

    public ProcessingInstruction createProcessingInstruction(String target, String data) {
        return new DefaultProcessingInstruction(target, data);
    }

    public ProcessingInstruction createProcessingInstruction(String target, Map data) {
        return new DefaultProcessingInstruction(target, data);
    }

    public QName createQName(String localName, Namespace namespace) {
        return cache.get(localName, namespace);
    }

    public QName createQName(String localName) {
        return cache.get(localName);
    }

    public QName createQName(String name, String prefix, String uri) {
        return cache.get(name, AbstractNamespace.get( prefix, uri ));
    }

    public QName createQName(String qualifiedName, String uri) {
        return cache.get(qualifiedName, uri);
    }

    /** <p><code>createXPath</code> parses an XPath expression
      * and creates a new XPath <code>XPath</code> instance.</p>
      *
      * @param xpathExpression is the XPath expression to create
      * @return a new <code>XPath</code> instance
      * @throws InvalidXPathException if the XPath expression is invalid
      */
    public XPath createXPath(String xpathExpression) throws InvalidXPathException {
        DefaultXPath xpath = new DefaultXPath( xpathExpression );
        if ( xpathNamespaceURIs != null ) {
            xpath.setNamespaceURIs( xpathNamespaceURIs );
        }
        return xpath;
    }

    /** <p><code>createXPath</code> parses an XPath expression
      * and creates a new XPath <code>XPath</code> instance.</p>
      *
      * @param xpathExpression is the XPath expression to create
      * @param variableContext is the variable context to use when evaluating the XPath
      * @return a new <code>XPath</code> instance
      * @throws InvalidXPathException if the XPath expression is invalid
      */
    public XPath createXPath(String xpathExpression, VariableContext variableContext) {
        XPath xpath = createXPath( xpathExpression );
        xpath.setVariableContext( variableContext );
        return xpath;
    }

    /** <p><code>createXPathFilter</code> parses a NodeFilter
      * from the given XPath filter expression.
      * XPath filter expressions occur within XPath expressions such as
      * <code>self::node()[ filterExpression ]</code></p>
      *
      * @param xpathFilterExpression is the XPath filter expression
      * to create
      * @param variableContext is the variable context to use when evaluating the XPath
      * @return a new <code>NodeFilter</code> instance
      */
    public NodeFilter createXPathFilter(String xpathFilterExpression, VariableContext variableContext) {
        XPath answer = createXPath( xpathFilterExpression );
        //DefaultXPath answer = new DefaultXPath( xpathFilterExpression );
        answer.setVariableContext( variableContext );
        return answer;
    }

    /** <p><code>createXPathFilter</code> parses a NodeFilter
      * from the given XPath filter expression.
      * XPath filter expressions occur within XPath expressions such as
      * <code>self::node()[ filterExpression ]</code></p>
      *
      * @param xpathFilterExpression is the XPath filter expression
      * to create
      * @return a new <code>NodeFilter</code> instance
      */
    public NodeFilter createXPathFilter(String xpathFilterExpression) {
        return createXPath( xpathFilterExpression );
        //return new DefaultXPath( xpathFilterExpression );
    }

    /** <p><code>createPattern</code> parses the given
      * XPath expression to create an XSLT style {@link Pattern} instance
      * which can then be used in an XSLT processing model.</p>
      *
      * @param xpathPattern is the XPath pattern expression
      * to create
      * @return a new <code>Pattern</code> instance
      */
    public Pattern createPattern(String xpathPattern) {
        return new XPathPattern( xpathPattern );
    }


    // Properties
    //-------------------------------------------------------------------------

    /** Returns a list of all the QName instances currently used by this document factory
     */
    public List getQNames() {
        return cache.getQNames();
    }

    /** @return the Map of namespace URIs that will be used by by XPath expressions
     * to resolve namespace prefixes into namespace URIs. The map is keyed by
     * namespace prefix and the value is the namespace URI. This value could well be
     * null to indicate no namespace URIs are being mapped.
     */
    public Map getXPathNamespaceURIs() {
        return xpathNamespaceURIs;
    }

    /** Sets the namespace URIs to be used by XPath expressions created by this factory
     * or by nodes associated with this factory. The keys are namespace prefixes and the
     * values are namespace URIs.
     */
    public void setXPathNamespaceURIs(Map xpathNamespaceURIs) {
        this.xpathNamespaceURIs = xpathNamespaceURIs;
    }

    // Implementation methods
    //-------------------------------------------------------------------------


    /** <p><code>createSingleton</code> creates the singleton instance
      * from the given class name.</p>
      *
      * @param className is the name of the DocumentFactory class to use
      * @return a new singleton instance.
      */
    protected static DocumentFactory createSingleton(String className) {
        // let's try and class load an implementation?
        try {
            // I'll use the current class loader
            // that loaded me to avoid problems in J2EE and web apps
            Class theClass = Class.forName(
                className,
                true,
                DocumentFactory.class.getClassLoader()
            );
            return (DocumentFactory) theClass.newInstance();
        }
        catch (Throwable e) {
            System.out.println( "WARNING: Cannot load DocumentFactory: " + className );
            return new DocumentFactory();
        }
    }

    /** @return the cached QName instance if there is one or adds the given
      * qname to the cache if not
       */
    protected QName intern(QName qname) {
        return cache.intern(qname);
    }

    /** Factory method to create the QNameCache. This method should be overloaded
      * if you wish to use your own derivation of QName.
      */
    protected QNameCache createQNameCache() {
        return new QNameCache(this);
    }



    private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
        in.defaultReadObject();
        init();
    }

    protected void init() {
        cache = createQNameCache();
    }
}




/*
 * Redistribution and use of this software and associated documentation
 * ("Software"), with or without modification, are permitted provided
 * that the following conditions are met:
 *
 * 1. Redistributions of source code must retain copyright
 *    statements and notices.  Redistributions must also contain a
 *    copy of this document.
 *
 * 2. Redistributions in binary form must reproduce the
 *    above copyright notice, this list of conditions and the
 *    following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 *
 * 3. The name "DOM4J" must not be used to endorse or promote
 *    products derived from this Software without prior written
 *    permission of MetaStuff, Ltd.  For written permission,
 *    please contact [e-mail].
 *
 * 4. Products derived from this Software may not be called "DOM4J"
 *    nor may "DOM4J" appear in their names without prior written
 *    permission of MetaStuff, Ltd. DOM4J is a registered
 *    trademark of MetaStuff, Ltd.
 *
 * 5. Due credit should be given to the DOM4J Project
 *    (http://dom4j.org/).
 *
 * THIS SOFTWARE IS PROVIDED BY METASTUFF, LTD. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
 * METASTUFF, LTD. OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Copyright 2001 (C) MetaStuff, Ltd. All Rights Reserved.
 *
 * $Id: DocumentFactory.java,v 1.3 2003/11/02 17:55:20 per_nyfelt Exp $
 */