namespacestack.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: NamespaceStack.java,v 1.5 2003/11/02 18:04:59 per_nyfelt Exp $
 */

package org.dom4j.tree;

import org.dom4j.*;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

/** NamespaceStack implements a stack of namespaces and optionally
  * maintains a cache of all the fully qualified names (<code>QName</code>)
  * which are in scope. This is useful when building or navigating a <i>dom4j</i>
  * document.
  *
  * @author <a href="mailto:[e-mail]">James Strachan</a>
  * @version $Revision: 1.5 $
  */
public class NamespaceStack {

    /** The factory used to create new <code>AbstractNamespace</code> instances */
    private NodeFactory nodeFactory;

    /** The Stack of namespaces */
    private ArrayList namespaceStack = new ArrayList();

    /** The cache of qualifiedNames to QNames per namespace context */
    private ArrayList namespaceCacheList = new ArrayList();

    /** A cache of current namespace context cache of mapping from qualifiedName to QName */
    private Map currentNamespaceCache;

    /** A cache of mapping from qualifiedName to QName before any namespaces are declared */
    private Map rootNamespaceCache = new HashMap();


    /** Caches the default namespace defined via xmlns="" */
    private Namespace defaultNamespace;


    public NamespaceStack() {
        this.nodeFactory = DocumentFactory.getInstance();
    }

    /**
     * @deprecated      Use NamespaceStack(NodeFactory) instead.
     */
    public NamespaceStack(DocumentFactory documentFactory) {
        this.nodeFactory = documentFactory;
    }

    public NamespaceStack(NodeFactory nodeFactory) {
        this.nodeFactory = nodeFactory;
    }

    /** Pushes the given namespace onto the stack so that its prefix
      * becomes available.
      *
      * @param namespace is the <code>AbstractNamespace</code> to add to the stack.
      */
    public void push(Namespace namespace) {
        namespaceStack.add( namespace );
        namespaceCacheList.add( null );
        currentNamespaceCache = null;
        String prefix = namespace.getPrefix();
        if ( prefix == null || prefix.length() == 0 ) {
            defaultNamespace = namespace;
        }
    }

    /** Pops the most recently used <code>AbstractNamespace</code> from
      * the stack
      *
      * @return AbstractNamespace popped from the stack
      */
    public Namespace pop() {
        return remove( namespaceStack.size() - 1 );
    }

    /** @return the number of namespaces on the stackce stack.
     */
    public int size() {
        return namespaceStack.size();
    }

    /** Clears the stack
      */
    public void clear() {
        namespaceStack.clear();
        namespaceCacheList.clear();
        rootNamespaceCache.clear();
        currentNamespaceCache = null;
    }

    /** @return the namespace at the specified index on the stack
      */
    public AbstractNamespace getNamespace( int index ) {
        return (AbstractNamespace) namespaceStack.get( index );
    }

    /** @return the namespace for the given prefix or null
      * if it could not be found.
      */
    public Namespace getNamespaceForPrefix( String prefix ) {
        if ( prefix == null ) {
            prefix = "";
        }
        for ( int i = namespaceStack.size() - 1; i >= 0; i-- ) {
            Namespace namespace = (Namespace) namespaceStack.get(i);
            if ( prefix.equals( namespace.getPrefix() ) ) {
                return namespace;
            }
        }
        return null;
    }

    /** @return the URI for the given prefix or null if it
      * could not be found.
      */
    public String getURI( String prefix ) {
        Namespace namespace = getNamespaceForPrefix( prefix );
        return ( namespace != null ) ? namespace.getURI() : null;
    }

    /** @return true if the given prefix is in the stack.
      */
    public boolean contains( Namespace namespace ) {
        String prefix = namespace.getPrefix();
        Namespace current = null;
        if ( prefix == null || prefix.length() == 0 ) {
            current = getDefaultNamespace();
        }
        else {
            current = getNamespaceForPrefix( prefix );
        }
        if ( current == null ) {
            return false;
        }
        if ( current == namespace ) {
            return true;
        }
        return namespace.getURI().equals( current.getURI() );
    }

    public QName getQName( String namespaceURI, String localName, String qualifiedName ) {
        if ( localName == null ) {
            localName = qualifiedName;
        }
        else if ( qualifiedName == null ) {
            qualifiedName = localName;
        }
        if ( namespaceURI == null ) {
            namespaceURI = "";
        }
        String prefix = "";
        int index = qualifiedName.indexOf(":");
        if (index > 0) {
            prefix = qualifiedName.substring(0, index);
            if (localName.trim().length() == 0) {
                localName = qualifiedName.substring(index+1);
            }
        } else if (localName.trim().length() == 0) {
            localName = qualifiedName;
        }
        Namespace namespace = createNamespace( prefix, namespaceURI );
        return pushQName( localName, qualifiedName, namespace, prefix );
    }

    public QName getAttributeQName( String namespaceURI, String localName, String qualifiedName ) {
        if ( qualifiedName == null ) {
            qualifiedName = localName;
        }
        Map map = getNamespaceCache();
        QName answer = (QName) map.get( qualifiedName );
        if ( answer != null ) {
            return answer;
        }
        if ( localName == null ) {
            localName = qualifiedName;
        }
        if ( namespaceURI == null ) {
            namespaceURI = "";
        }
        Namespace namespace = null;
        String prefix = "";
        int index = qualifiedName.indexOf(":");
        if (index > 0) {
            prefix = qualifiedName.substring(0, index);
            namespace = createNamespace( prefix, namespaceURI );
            if ( localName.trim().length() == 0) {
                localName = qualifiedName.substring(index+1);
            }
        }
        else {
            // attributes with no prefix have no namespace
            namespace = AbstractNamespace.NO_NAMESPACE;
            if ( localName.trim().length() == 0) {
                localName = qualifiedName;
            }
        }
        answer = pushQName( localName, qualifiedName, namespace, prefix );
        map.put( qualifiedName, answer );
        return answer;
    }

    /** Adds a namepace to the stack with the given prefix and URI */
    public void push( String prefix, String uri ) {
        if ( uri == null ) {
            uri = "";
        }
        Namespace namespace = createNamespace( prefix, uri );
        push( namespace );
    }

    /** Adds a new namespace to the stack */
    public Namespace addNamespace( String prefix, String uri ) {
        Namespace namespace = createNamespace( prefix, uri );
        push( namespace );
        return namespace;
    }

    /** Pops a namepace from the stack with the given prefix and URI */
    public Namespace pop( String prefix ) {
        if ( prefix == null ) {
            prefix = "";
        }
        Namespace namespace = null;
        for (int i = namespaceStack.size() - 1; i >= 0; i-- ) {
            Namespace ns = (Namespace) namespaceStack.get(i);
            if ( prefix.equals( ns.getPrefix() ) ) {
                remove(i);
                namespace = ns;
                break;
            }
        }
        if ( namespace == null ) {
            System.out.println( "Warning: missing namespace prefix ignored: " + prefix );
        }
        return namespace;
    }

    public String toString() {
        return super.toString() + " Stack: " + namespaceStack.toString();
    }

    /**
     * @deprecated      Use getNodeFactory() instead
     */
    public DocumentFactory getDocumentFactory() {
        if (getNodeFactory() instanceof XPathFactory) {
            return new DelegateDocumentFactory(getNodeFactory(), (XPathFactory) getNodeFactory());
        } else {
            return new DelegateDocumentFactory(getNodeFactory(), DocumentFactory.getInstance());
        }
    }

    /**
     * @deprecated      Use setNodeFactory(NodeFactory) instead
     */
    public void setDocumentFactory(DocumentFactory documentFactory) {
        this.nodeFactory = documentFactory;
    }

    public NodeFactory getNodeFactory() {
        return nodeFactory;
    }

    public void setNodeFactory(NodeFactory nodeFactory) {
        this.nodeFactory = nodeFactory;
    }

    public Namespace getDefaultNamespace() {
        if ( defaultNamespace == null ) {
            defaultNamespace = findDefaultNamespace();
        }
        return defaultNamespace;
    }

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

    /** Adds the QName to the stack of available QNames
      */
    protected QName pushQName( String localName, String qualifiedName, Namespace namespace, String prefix ) {
        if ( prefix == null || prefix.length() == 0 ) {
            this.defaultNamespace = null;
        }
        return createQName( localName, qualifiedName, namespace );
    }

    /** Factory method to creeate new QName instances. By default this method
      * interns the QName
      */
    protected QName createQName( String localName, String qualifiedName, Namespace namespace ) {
        return getNodeFactory().createQName( localName, namespace );
    }

    /** Factory method to creeate new AbstractNamespace instances. By default this method
      * interns the AbstractNamespace
      */
    protected Namespace createNamespace( String prefix, String namespaceURI ) {
        return getNodeFactory().createNamespace( prefix, namespaceURI );
    }

    /** Attempts to find the current default namespace on the stack right now or returns null if one
      * could not be found
      */
    protected Namespace findDefaultNamespace() {
        for ( int i = namespaceStack.size() - 1; i >= 0; i-- ) {
            Namespace namespace = (Namespace) namespaceStack.get(i);
            if ( namespace != null ) {
                String prefix = namespace.getPrefix();
                if ( prefix == null || namespace.getPrefix().length() == 0 ) {
                    return namespace;
                }
            }
        }
        return null;
    }

    /** Removes the namespace at the given index of the stack */
    protected Namespace remove(int index) {
        Namespace namespace = (Namespace) namespaceStack.remove(index);
        namespaceCacheList.remove(index);
        defaultNamespace = null;
        currentNamespaceCache = null;
        return namespace;
    }

    protected Map getNamespaceCache() {
        if ( currentNamespaceCache == null ) {
            int index = namespaceStack.size() - 1;
            if ( index < 0 ) {
                currentNamespaceCache = rootNamespaceCache;
            }
            else {
                currentNamespaceCache = (Map) namespaceCacheList.get(index);
                if ( currentNamespaceCache == null ) {
                    currentNamespaceCache = new HashMap();
                    namespaceCacheList.set(index, currentNamespaceCache);
                }
            }
        }
        return currentNamespaceCache;
    }
}




/*
 * 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: NamespaceStack.java,v 1.5 2003/11/02 18:04:59 per_nyfelt Exp $
 */