/* DomCharacterData.java -- 
   Copyright (C) 1999,2000,2001,2004,2006 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
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this exception to your version of the library, but you are not
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exception statement from your version. */

package gnu.xml.dom;

import org.w3c.dom.CharacterData;
import org.w3c.dom.DOMException;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.events.MutationEvent;


/**
 * <p> Abstract "CharacterData" implementation.  This
 * facilitates reusing code in classes implementing subtypes of that DOM
 * interface (Text, Comment, CDATASection).  </p>
 *
 * @author David Brownell
 * @author <a href='mailto:dog@gnu.org'>Chris Burdess</a>
 */
public abstract class DomCharacterData
  extends DomNode
  implements CharacterData
{

  /**
   * Empty node list representing the children of character data nodes.
   */
  static class EmptyNodeList
    implements NodeList
  {

    public int getLength()
    {
      return 0;
    }

    public Node item(int index)
    {
      return null;
    }
    
  }

  /**
   * Singleton empty node list for character data nodes.
   */
  static final NodeList CHILD_NODES = new EmptyNodeList();

  private String text;
  
  // package private
  DomCharacterData(short nodeType, DomDocument doc, String value)
  {
    super(nodeType, doc);
    text = (value == null) ? "" : value;
  }

  // package private
  DomCharacterData(short nodeType, DomDocument doc,
                   char[] buf, int offset, int length)
  {
    super(nodeType, doc);
    text = (buf == null) ? "" : new String(buf, offset, length);
  }

  /**
   * <b>DOM L1</b>
   * Appends the specified data to the value of this node.
   * Causes a DOMCharacterDataModified mutation event to be reported.
   */
  public void appendData(String arg)
  {
    if (isReadonly())
      {
        throw new DomDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
      }
    String value = text + arg;
    mutating(value);
    text = value;
  }
  
  /**
   * <b>DOM L1</b>
   * Modifies the value of this node.
   * Causes a DOMCharacterDataModified mutation event to be reported.
   */
  public void deleteData(int offset, int count)
  {
    if (isReadonly())
      {
        throw new DomDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
      }
    char[] raw = text.toCharArray();
    if (offset < 0 || count < 0 || offset > raw.length)
      {
        throw new DomDOMException(DOMException.INDEX_SIZE_ERR);
      }
    if ((offset + count) > raw.length)
      {
        count = raw.length - offset;
      }
    if (count == 0)
      {
        return;
      }
    try
      {
        char[] buf = new char[raw.length - count];
        System.arraycopy(raw, 0, buf, 0, offset);
        System.arraycopy(raw, offset + count, buf, offset,
                         raw.length - (offset + count));
        String value = new String(buf);
        mutating(value);
        text = value;
      }
    catch (IndexOutOfBoundsException x)
      {
        throw new DomDOMException(DOMException.INDEX_SIZE_ERR);
      }
  }
    
  /**
   * <b>DOM L1</b>
   * Returns the value of this node.
   */
  public String getNodeValue()
  {
    return text;
  }
    
  /**
   * <b>DOM L1</b>
   * Returns the value of this node; same as getNodeValue.
   */
  public final String getData()
  {
    return text;
  }

  /**
   * <b>DOM L1</b>
   * Returns the length of the data.
   */
  public int getLength()
  {
    return text.length();
  }
  
  /**
   * <b>DOM L1</b>
   * Modifies the value of this node.
   */
  public void insertData(int offset, String arg)
  {
    if (isReadonly())
      {
      throw new DomDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
      }
    char[] raw = text.toCharArray();
    char[] tmp = arg.toCharArray ();
    char[] buf = new char[raw.length + tmp.length];
    
    try
      {
        System.arraycopy(raw, 0, buf, 0, offset);
        System.arraycopy(tmp, 0, buf, offset, tmp.length);
        System.arraycopy(raw, offset, buf, offset + tmp.length,
                         raw.length - offset);
        String value = new String(buf);
        mutating(value);
        text = value;
      }
    catch (IndexOutOfBoundsException x)
      {
        throw new DomDOMException(DOMException.INDEX_SIZE_ERR);
      }
  }
    
  /**
   * <b>DOM L1</b>
   * Modifies the value of this node.  Causes DOMCharacterDataModified
   * mutation events to be reported (at least one).
   */
  public void replaceData(int offset, int count, String arg)
  {
    if (readonly)
      {
        throw new DomDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
      }
    char[] raw = text.toCharArray();
    
    // deleteData
    if (offset < 0 || count < 0 || offset > raw.length)
      {
        throw new DomDOMException(DOMException.INDEX_SIZE_ERR);
      }
    if ((offset + count) > raw.length)
      {
        count = raw.length - offset;
      }
    try
      {
        char[] buf = new char[raw.length - count];
        System.arraycopy(raw, 0, buf, 0, offset);
        System.arraycopy(raw, offset + count, buf, offset,
                         raw.length - (offset + count));
        
        // insertData
        char[] tmp = arg.toCharArray ();
        char[] buf2 = new char[buf.length + tmp.length];
        System.arraycopy(raw, 0, buf, 0, offset);
        System.arraycopy(tmp, 0, buf, offset, tmp.length);
        System.arraycopy(raw, offset, buf, offset + tmp.length,
                         raw.length - offset);
        String value = new String(buf);
        mutating(value);
        text = value;
      }
    catch (IndexOutOfBoundsException x)
      {
        throw new DomDOMException(DOMException.INDEX_SIZE_ERR);
      }
  }
    
  /**
   * <b>DOM L1</b>
   * Assigns the value of this node.
   * Causes a DOMCharacterDataModified mutation event to be reported.
   */
  public void setNodeValue(String value)
  {
    if (isReadonly())
      {
        throw new DomDOMException(DOMException.NO_MODIFICATION_ALLOWED_ERR);
      }
    if (value == null)
      {
        value = "";
      }
    mutating(value);
    text = value;
  }
 
  /**
   * <b>DOM L1</b>
   * Assigns the value of this node; same as setNodeValue.
   */
  final public void setData(String data)
  {
    setNodeValue(data);
  }

  /**
   * <b>DOM L1</b>
   * Returns the specified substring.
   */
  public String substringData(int offset, int count)
  {
    try
      {
        return text.substring(offset, count);
      }
    catch (StringIndexOutOfBoundsException e)
      {
        if (offset >= 0 && count >= 0 && offset < text.length())
          {
            return text.substring(offset);
          }
        throw new DomDOMException(DOMException.INDEX_SIZE_ERR);
      }
  }

  /**
   * Returns an empty node list.
   * Character data nodes do not have children.
   */
  public NodeList getChildNodes()
  {
    return CHILD_NODES;
  }

  /**
   * The base URI for character data is <code>null</code>.
   * @since DOM Level 3 Core
   */
  public final String getBaseURI()
  {
    return null;
  }

  private void mutating(String newValue)
  {
    if (!reportMutations)
      {
        return;
      }
    
    // EVENT:  DOMCharacterDataModified, target = this,
    //  prev/new values provided
    MutationEvent  event;
    
    event = (MutationEvent) createEvent("MutationEvents");
    event.initMutationEvent("DOMCharacterDataModified",
                            true /* bubbles */, false /* nocancel */,
                            null, text, newValue, null, (short) 0);
    dispatchEvent(event);
  }
  
}