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

package org.dom4j.tree;

import org.dom4j.*;
import org.dom4j.io.OutputFormat;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.StringTokenizer;

/** <p><code>AbstractBranch</code> is an abstract base class for
  * tree implementors to use for implementation inheritence.</p>
  *
  * @author <a href="mailto:[e-mail]">James Strachan</a>
  * @version $Revision: 1.4 $
  */
public abstract class AbstractBranch extends AbstractNode implements Branch {

    /** The output format used by default */
    protected static final OutputFormat outputFormat = new OutputFormat();

    protected static final int DEFAULT_CONTENT_LIST_SIZE = 5;


    public AbstractBranch() {
    }


    public boolean isReadOnly() {
        return false;
    }

    public boolean hasContent() {
        return nodeCount() > 0;
    }

    public List content() {
        List backingList = contentList();
        return new ContentListFacade(this, backingList);
    }

    public String getText() {
        List content = contentList();
        if (content != null) {
            int size = content.size();
            if (size >= 1) {
                Object first = content.get(0);
                String firstText = getContentAsText( first );
                if (size == 1) {
                    // optimised to avoid StringBuffer creation
                    return firstText;
                }
                else {
                    StringBuffer buffer = new StringBuffer( firstText );
                    for ( int i = 1; i < size; i++ ) {
                        Object node = content.get(i);
                        buffer.append( getContentAsText( node ) );
                    }
                    return buffer.toString();
                }
            }
        }
        return "";
    }

    /** @return the text value of the given content object
     * as text which returns the text value of CDATA, Entity or Text nodes
     */
    protected String getContentAsText(Object content) {
        if ( content instanceof Node) {
            Node node = (Node) content;
            switch ( node.getNodeType() ) {
                case CDATA_SECTION_NODE:
                //case ENTITY_NODE:
                case ENTITY_REFERENCE_NODE:
                case TEXT_NODE:
                    return node.getText();
            }
        }
        else if ( content instanceof String) {
            return (String) content;
        }
        return "";
    }

    /** @return the XPath defined string-value of the given content object
     */
    protected String getContentAsStringValue(Object content) {
        if ( content instanceof Node) {
            Node node = (Node) content;
            switch ( node.getNodeType() ) {
                case CDATA_SECTION_NODE:
                //case ENTITY_NODE:
                case ENTITY_REFERENCE_NODE:
                case TEXT_NODE:
                case ELEMENT_NODE:
                    return node.getStringValue();
            }
        }
        else if ( content instanceof String) {
            return (String) content;
        }
        return "";
    }


    public String getTextTrim() {
        String text = getText();

        StringBuffer textContent = new StringBuffer();
        StringTokenizer tokenizer = new StringTokenizer(text);
        while (tokenizer.hasMoreTokens()) {
            String str = tokenizer.nextToken();
            textContent.append(str);
            if (tokenizer.hasMoreTokens()) {
                textContent.append(" ");  // separator
            }
        }

        return textContent.toString();
    }

    public void setProcessingInstructions(List listOfPIs) {
        for ( Iterator iter = listOfPIs.iterator(); iter.hasNext(); ) {
            ProcessingInstruction pi = (ProcessingInstruction) iter.next();
            addNode(pi);
        }
    }

    public Element addElement(String name) {
        Element node = getNodeFactory().createElement( name );
        add( node );
        return node;
    }

    public Element addElement(String qualifiedName, String namespaceURI) {
        Element node = getNodeFactory().createElement( qualifiedName, namespaceURI );
        add( node );
        return node;
    }

    public Element addElement(QName qname) {
        Element node = getNodeFactory().createElement( qname );
        add( node );
        return node;
    }

    public Element addElement(String name, String prefix, String uri) {
        Namespace namespace = AbstractNamespace.get( prefix, uri );
        QName qName = getNodeFactory().createQName( name, namespace );
        return addElement( qName );
    }

    // polymorphic node methods

    public void add(Node node) {
        switch ( node.getNodeType() ) {
            case ELEMENT_NODE:
                add((Element) node);
                break;
            case COMMENT_NODE:
                add((Comment) node);
                break;
            case PROCESSING_INSTRUCTION_NODE:
                add((ProcessingInstruction) node);
                break;
            default:
                invalidNodeTypeAddException(node);
        }
    }

    public boolean remove(Node node) {
        switch ( node.getNodeType() ) {
            case ELEMENT_NODE:
                return remove((Element) node);
            case COMMENT_NODE:
                return remove((Comment) node);
            case PROCESSING_INSTRUCTION_NODE:
                return remove((ProcessingInstruction) node);
            default:
                invalidNodeTypeAddException(node);
                return false;
        }
    }

    // typesafe versions using node classes

    public void add(Comment comment) {
        addNode(comment);
    }

    public void add(Element element) {
        addNode(element);
    }

    public void add(ProcessingInstruction pi) {
        addNode(pi);
    }

    public boolean remove(Comment comment) {
        return removeNode(comment);
    }

    public boolean remove(Element element) {
        return removeNode(element);
    }

    public boolean remove(ProcessingInstruction pi) {
        return removeNode(pi);
    }


    public Element elementByID(String elementID) {
        for ( int i = 0, size = nodeCount(); i < size; i++ ) {
            Node node = node(i);
            if ( node instanceof Element ) {
                Element element = (Element) node;
                String id = elementID(element);
                if ( id != null && id.equals( elementID ) ) {
                    return element;
                }
                else {
                    element = element.elementByID( elementID );
                    if ( element != null ) {
                        return element;
                    }
                }
            }
        }
        return null;
    }

    public void appendContent(Branch branch) {
        for ( int i = 0, size = branch.nodeCount(); i < size; i++ ) {
            Node node = branch.node(i);
            add( (Node) node.clone() );
        }
    }


    public Node node(int index) {
        Object object = contentList().get(index);
        if (object instanceof Node) {
            return (Node) object;
        }
        if (object instanceof String) {
            return getNodeFactory().createText(object.toString());
        }
        return null;
    }

    public int nodeCount() {
        return contentList().size();
    }

    public int indexOf(Node node) {
        return contentList().indexOf( node );
    }

    public Iterator nodeIterator() {
        return contentList().iterator();
    }


    // Implementation methods

    /** @return the ID of the given <code>Element</code>
      */
    protected String elementID(Element element) {
        // XXX: there will be other ways of finding the ID
        // XXX: should probably have an IDResolver or something
        return element.attributeValue( "ID" );
    }

    /** @return the internal List used to manage the content */
    protected abstract List contentList();

    /** A Factory Method pattern which creates
      * a List implementation used to store content
      */
    protected List createContentList() {
        return new ArrayList( DEFAULT_CONTENT_LIST_SIZE );
    }

    /** A Factory Method pattern which creates
      * a List implementation used to store content
      */
    protected List createContentList(int size) {
        return new ArrayList( size );
    }


    /** A Factory Method pattern which creates
      * a BackedList implementation used to store results of
      * a filtered content query.     */
    protected BackedList createResultList() {
        return new BackedList( this, contentList() );
    }

    /** A Factory Method pattern which creates
      * a BackedList implementation which contains a single result
      */
    protected List createSingleResultList( Object result ) {
        BackedList list = new BackedList( this, contentList(), 1 );
        list.addLocal( result );
        return list;
    }

    /** A Factory Method pattern which creates an empty
      * a BackedList implementation
      */
    protected List createEmptyList() {
        return new BackedList( this, contentList(), 0 );
    }


    protected abstract void addNode(Node node);

    protected abstract void addNode(int index, Node node);

    protected abstract boolean removeNode(Node node);


    /** Called when a new child node has been added to me
      * to allow any parent relationships to be created or
      * events to be fired.
      */
    protected abstract void childAdded(Node node);

    /** Called when a child node has been removed
      * to allow any parent relationships to be deleted or
      * events to be fired.
      */
    protected abstract void childRemoved(Node node);

    /** Called when the given List content has been removed so
      * each node should have its parent and document relationships
      * cleared
      */
    protected void contentRemoved() {
        List content = contentList();
        for ( int i = 0, size = content.size(); i < size; i++ ) {
            Object object = content.get(i);
            if ( object instanceof Node ) {
                 childRemoved( (Node) object );
            }
        }
    }

    /** Called when an invalid node has been added.
      * Throws an {@link IllegalAddException}.
      */
    protected void invalidNodeTypeAddException(Node node) {
        throw new IllegalAddException( "Invalid node type. Cannot add node: " + node + " to this branch: " + this );
    }


}




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