litexmlelement.java

jxta_src_2.41b jxta 2.41b 最新版源码 from www.jxta.org

/*
 * $Id: LiteXMLElement.java,v 1.46 2005/06/15 03:09:33 bondolo Exp $
 ********************
 *
 * Copyright (c) 2001 Sun Microsystems, Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 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 end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *       Sun Microsystems, Inc. for Project JXTA."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact Project JXTA at http://www.jxta.org.
 *
 * 5. Products derived from this software may not be called "JXTA",
 *    nor may "JXTA" appear in their name, without prior written
 *    permission of Sun.
 *
 * THIS SOFTWARE IS PROVIDED ``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 SUN MICROSYSTEMS 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.
 *
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Project JXTA.  For more
 * information on Project JXTA, please see
 * <http://www.jxta.org/>.
 *
 * This license is based on the BSD license adopted by the Apache Foundation.
 ********************
 */

package net.jxta.impl.document;


import java.io.Writer;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;

import java.io.IOException;

import org.apache.log4j.Level;
import org.apache.log4j.Logger;

import net.jxta.document.Attributable;
import net.jxta.document.Attribute;
import net.jxta.document.Element;
import net.jxta.document.StructuredDocument;
import net.jxta.document.TextElement;


/**
 * An element of a <CODE>StructuredDocument</CODE>. <CODE>StructuredDocument</CODE>s
 * are made up of hierarchies of elements. LiteXMLElement is part of an implementation
 * while makes use of XML-style document conventions, but without the overhead of a
 * full parser.
 *
 */
public class LiteXMLElement extends XMLElementCommon {
    
    /**
     * Defines a range of characters, probably within a string. The range is
     * deemed to be invalid if 'start' is -1.  A zero length range is, by 
     * convention, described by an 'end' value of 'start' - 1.
     */
    protected static class charRange implements Comparable {
        
        /**
         *  Contains the start position of this range.
         **/
        public int start;
        
        /**
         * Contains the end position of this range. one weird thing: if end == start -1,
         * then the item is of zero length begining at start.
         **/
        public int end;
        
        /**
         * Constructor for a null charRange.
         **/
        public charRange() {
            start = -1;
            end = -1;
        }
        
        /**
         * Constructor for which the bounds are specified.
         *
         **/
        public charRange(int start, int end) {
            this.start = start;
            this.end = end;
        }
        
        /**
         * {@inheritDoc}
         **/
        public boolean equals(Object aRange) {
            if (this == aRange) {
                return true;
            }
            
            if (!(aRange instanceof charRange)) {
                return false;
            }
            
            charRange someRange = (charRange) aRange;
            
            return (start == someRange.start) && (end == someRange.end);
        }
        
        /**
         * {@inheritDoc}
         **/
        public int compareTo(Object aRange) {
            if (this == aRange) {
                return 0;
            }
            
            if (!(aRange instanceof charRange)) {
                throw new ClassCastException("type mismatch error");
            }
            
            charRange someRange = (charRange) aRange;
            
            if (start < someRange.start) {
                return -1;
            }
            
            if (start > someRange.start) {
                return 1;
            }
            
            if (end < someRange.end) {
                return -1;
            }
            
            if (end > someRange.end) {
                return 1;
            }
            
            return 0;
        }
        
        /**
         * {@inheritDoc}
         **/
        public String toString() {
            return "[" + start + "," + end + "]";
        }
        
        /**
         * Returns true if the <CODE>charRange</CODE> specified by someRange is
         * contained within this range.
         *
         * @param someRange The range which must be contained within this range.
         *
         * @return true if the specified range is contained with this range otherwise false.
         **/
        public boolean contains(charRange someRange) {
            return(isValid() && someRange.isValid() && (start <= someRange.start) && (end >= someRange.end));
        }
        
        /**
         * Returns true if the <CODE>tagRange</CODE> specified by someRange is
         * contained within this range.
         *
         * @param someRange The range which must be contained within this range.
         *
         * @return true if the specified range is contained with this range otherwise false.
         **/
        public boolean contains(tagRange someRange) {
            return(isValid() && someRange.isValid() && (start <= someRange.startTag.start) && (end >= someRange.endTag.end));
        }
        
        /**
         *  Returns true if the location specified is contained in this range.
         *
         *  @param someLoc the location which is to be tested.
         *  @return true if the location is in this range, otherwise false.
         */
        public boolean contains(int someLoc) {
            return(isValid() && (someLoc >= 0) && (start <= someLoc) && (end >= someLoc));
        }
        
        /**
         * Returns true if the range is both non-null and has a length of greater
         * than or equal to zero.
         *
         * @return true if the range is a valid one, otherwise false.
         *
         **/
        public boolean isValid() {
            return length() >= 0;
        }
        
        /**
         * Returns the length of this range.
         * @return The length of the range or -1 if the range is null.
         **/
        public int length() {
            if ((-1 == start) || (-1 == end)) {
                return -1;
            }
            
            return (end - start + 1);
        }
    }
    

    /**
     * A tagRange is a collection of char ranges useful for describing XML
     * structures.
     *
     * <p/><dl>
     * <dt><code>startTag</code></dt>
     * <dd>The range of the opening tag, ie. &lt;tag></dd>
     *  <dt><code>body</code></dt>
     *  <dd>Everything between <code>startTag</code> and <code>endTag</code>.</dd>
     *  <dt><code>endTag</code></dt>
     * <dd>The range of the terminating tag, ie. &lt;/tag>.</dd>
     * </dl>
     *
     * <p/>For empty-element tags the <code>startTag</code>, <code>body</code>
     * and <code>endTag</code> will be equal.
     **/
    protected static class tagRange implements Comparable {
        public charRange startTag;
        public charRange body;
        public charRange endTag;
        
        public tagRange() {
            startTag = new charRange();
            body = new charRange();
            endTag = new charRange();
        }
        
        public tagRange(charRange startTag, charRange body, charRange endTag) {
            this.startTag = startTag;
            this.body = body;
            this.endTag = endTag;
        }
        
        /**
         * {@inheritDoc}
         **/
        public boolean equals(Object aRange) {
            if (this == aRange) {
                return true;
            }
            
            if (!(aRange instanceof tagRange)) {
                return false;
            }
            
            tagRange likeMe = (tagRange) aRange;
            
            return startTag.equals(likeMe.startTag) && body.equals(likeMe.body) && endTag.equals(likeMe.endTag);
        }
        
        /**
         * {@inheritDoc}
         **/
        public int compareTo(Object aRange) {
            if (this == aRange) {
                return 0;
            }
            
            if (!(aRange instanceof tagRange)) {
                throw new ClassCastException("type mismatch error");
            }
            
            tagRange someRange = (tagRange) aRange;
            
            int compared = startTag.compareTo(someRange.startTag);
            
            if (0 != compared) {
                return compared;
            }
            
            return endTag.compareTo(someRange.endTag);
        }
        
        /**
         * {@inheritDoc}
         **/
        public String toString() {
            return startTag + ":" + body + ":" + endTag;
        }
        
        /**
         * Returns true if the <CODE>tagRange</CODE> specified by someRange is
         * contained within the body portion of this range.
         *
         * @param someRange The range which must be contained within this range.
         *
         * @return true if the specified range is contained with this range
         * otherwise false.
         */
        public boolean contains(tagRange someRange) {
            return(isValid() && someRange.isValid() && (body.start <= someRange.startTag.start) && (body.end >= someRange.endTag.end));
        }
        
        /**
         * Returns true if the <CODE>charRange</CODE> specified by someRange is
         * contained within the body portion of this range.
         *
         * @param someRange The range which must be contained within this range.
         *
         * @return true if the specified range is contained with this range
         * otherwise false.
         */
        public boolean contains(charRange someRange) {
            return(isValid() && someRange.isValid() && (body.start <= someRange.start) && (body.end >= someRange.end));
        }
        
        /**
         *  Returns <code>true</code> if this tagRange represents and empty
         *  element.
         **/
        public boolean isEmptyElement() {
            return isValid() && startTag.equals(body) && startTag.equals(endTag);
        }
        
        /**
         *
         **/
        public boolean isValid() {
            return (null != startTag) && (null != body) && (null != endTag) && startTag.isValid() && body.isValid() && endTag.isValid();
        }
    }
    
    /**
     *  Log4J Logger
     **/
    private final static transient Logger LOG = Logger.getLogger(LiteXMLElement.class.getName());
    
    /**
     * If true then every operation which modifies the state of the document will
     * perform a consistency check. This is a deadly performance killer but
     * helps a lot in isolating bugs.
     **/
    protected final static transient boolean paranoidConsistencyChecking = false;
    
    /**
     * Causes additional logging while parsing. This is a deadly performance
     * killer but helps a lot in isolating bugs.
     **/
    protected final static transient boolean verboseLogging = false;
    
    /**
     * The document associated with this Element.
     */
    protected final transient LiteXMLDocument doc;
    
    /**
     *  Identifies the element which is the parent of this element. If <code>
     *  this.parent == this</code> then this element is the root of the document.
     *  If <code>null == parent</code> then this element has not yet been
     *  inserted into the document.
     */
    protected transient Element parent;
    
    /**
     *  The portion of the source XML associated with this node
     */
    protected transient tagRange loc;
    
    /**
     *  If this node has yet to be inserted into the document then will contain
     *  the String value of this node, otherwise null.
     */
    private transient StringBuffer uninserted = null;
    
    /**
     * The child elements associated with this element
     */
    private final transient List children = new ArrayList();
    
    /**
     * Creates new LiteXMLElement
     *
     * @param loc The location of the element within the document.
     * @param doc The {@link LiteXMLDocument} which is the root of the document.
     **/
    protected LiteXMLElement(LiteXMLDocument doc, tagRange loc) {
        this.doc = doc;
        this.loc = loc;
    }
    
    /**
     * Creates new LiteElement
     *
     * @param doc The {@link LiteXMLDocument} which is the root of the document.
     * @param name The name of the element being created.
     * @param val The value of the element being created or null if there is no