qnamecache.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: QNameCache.java,v 1.4 2003/11/02 18:04:59 per_nyfelt Exp $
 */

package org.dom4j.tree;

import org.dom4j.DocumentFactory;
import org.dom4j.Namespace;
import org.dom4j.NodeFactory;
import org.dom4j.QName;

import java.util.*;

/** <p><code>QNameCache</code> caches instances of <code>QName</code>
  * for reuse both across documents and within documents.</p>
  *
  * @author <a href="mailto:[e-mail]">James Strachan</a>
  * @version $Revision: 1.4 $
  */
public class QNameCache {

    /** Cache of {@link org.dom4j.tree.DefaultQName} instances with no namespace */
    protected Map noNamespaceCache = Collections.synchronizedMap(new HashMap());

    /** Cache of {@link Map} instances indexed by namespace which contain
      * caches of {@link org.dom4j.tree.DefaultQName} for each name
      */
    protected Map namespaceCache = Collections.synchronizedMap(new HashMap());

    /** The document factory associated with new QNames instances in this cache
      * or null if no instances should be associated by default
      */
    private NodeFactory nodeFactory;


    public QNameCache() {
    }

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

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

    /** Returns a list of all the QName instances currently used
     */
    public List getQNames() {
        List answer = new ArrayList();
        answer.addAll( noNamespaceCache.values() );
        for ( Iterator iter = namespaceCache.values().iterator(); iter.hasNext(); ) {
            Map map = (Map) iter.next();
            answer.addAll( map.values() );
        }
        return answer;
    }

    /** @return the QName for the given name and no namepsace
      */
    public QName get(String name) {
        QName answer = null;
        if (name!=null) {
          answer=(QName) noNamespaceCache.get(name);
        }
        else {
          name="";
        }
        if (answer == null) {
            answer = createQName(name);
            answer.setNodeFactory(nodeFactory);
            noNamespaceCache.put(name, answer);
        }
        return answer;
    }

    /** @return the QName for the given local name and namepsace
      */
    public QName get(String name, Namespace namespace) {
        Map cache = getNamespaceCache(namespace);
        QName answer = null;
        if (name!=null) {
          answer=(QName) cache.get(name);
        }
        else {
          name="";
        }
        if (answer == null) {
            answer = createQName(name, namespace);
            answer.setNodeFactory(nodeFactory);
            cache.put(name, answer);
        }
        return answer;
    }


    /** @return the QName for the given local name, qualified name and namepsace
      */
    public QName get(String localName, Namespace namespace, String qualifiedName) {
        Map cache = getNamespaceCache(namespace);
        QName answer = null;
        if (localName!=null) {
          answer=(QName) cache.get(localName);
        }
        else {
          localName="";
        }

        if (answer == null) {
            answer = createQName(localName, namespace, qualifiedName);
            answer.setNodeFactory(nodeFactory);
            cache.put(localName, answer);
        }
        return answer;
    }


    public QName get(String qualifiedName, String uri) {
        int index = qualifiedName.indexOf( ':' );
        if ( index < 0 ) {
            return get( qualifiedName, AbstractNamespace.get( uri ) );
        }
        else {
            String name = qualifiedName.substring( index + 1 );
            String prefix = qualifiedName.substring( 0, index );
            return get(name, AbstractNamespace.get( prefix, uri ));
        }
    }


    /** @return the cached QName instance if there is one or adds the given
      * qname to the cache if not
       */
    public QName intern(QName qname) {
        return get(qname.getName(), qname.getNamespace(), qname.getQualifiedName());
    }

    /** @return the cache for the given namespace. If one does not
      * currently exist it is created.
      */
    protected Map getNamespaceCache(Namespace namespace) {
        if (namespace == AbstractNamespace.NO_NAMESPACE) {
            return noNamespaceCache;
        }
        Map answer = null;
        if (namespace!=null) {
          answer=(Map) namespaceCache.get(namespace);
        }
        if (answer == null) {
            answer = createMap();
            namespaceCache.put(namespace, answer);
        }
        return answer;
    }

    /** A factory method
      * @return a newly created {@link Map} instance.
      */
    protected Map createMap() {
        return Collections.synchronizedMap(new HashMap());
    }

    /** Factory method to create a new QName object
      * which can be overloaded to create derived QName instances
      */
    protected QName createQName(String name) {
        return new DefaultQName(name);
    }

    /** Factory method to create a new QName object
      * which can be overloaded to create derived QName instances
      */
    protected QName createQName(String name, Namespace namespace) {
        return new DefaultQName(name, namespace);
    }

    /** Factory method to create a new QName object
      * which can be overloaded to create derived QName instances
      */
    protected QName createQName(String name, Namespace namespace, String qualifiedName) {
        return new DefaultQName(name, namespace, qualifiedName);
    }
}




/*
 * 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: QNameCache.java,v 1.4 2003/11/02 18:04:59 per_nyfelt Exp $
 */