code: // AttributesImpl.java - default implementation of Attributes.
  // Written by David Megginson, sax@megginson.com
  // NO WARRANTY!  This class is in the public domain.
  
  // $Id: AttributesImpl.java,v 1.4 2002/09/29 02:55:48 okajima Exp $
  
  //fixed bug at removeAttribute!! by Daisuke OKAJIMA 2002.4.21
  
  package com.sun.xml.xsom.impl.parser.state;
  
  import org.xml.sax.Attributes;
  
  
  /**
   * Default implementation of the Attributes interface.
   *
   * <blockquote>
   * <em>This module, both source code and documentation, is in the
   * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
   * </blockquote>
   *
   * <p>This class provides a default implementation of the SAX2
   * {@link org.xml.sax.Attributes Attributes} interface, with the 
   * addition of manipulators so that the list can be modified or 
   * reused.</p>
   *
   * <p>There are two typical uses of this class:</p>
   *
   * <ol>
   * <li>to take a persistent snapshot of an Attributes object
   *  in a {@link org.xml.sax.ContentHandler#startElement startElement} event; or</li>
   * <li>to construct or modify an Attributes object in a SAX2 driver or filter.</li>
   * </ol>
   *
   * <p>This class replaces the now-deprecated SAX1 {@link 
   * org.xml.sax.helpers.AttributeListImpl AttributeListImpl}
   * class; in addition to supporting the updated Attributes
   * interface rather than the deprecated {@link org.xml.sax.AttributeList
   * AttributeList} interface, it also includes a much more efficient 
   * implementation using a single array rather than a set of Vectors.</p>
   *
   * @since SAX 2.0
   * @author David Megginson, 
   *         <a href="mailto:sax@megginson.com">sax@megginson.com</a>
   * @version 2.0
   */
  public class AttributesImpl implements Attributes
  {
  
  
      ////////////////////////////////////////////////////////////////////
      // Constructors.
      ////////////////////////////////////////////////////////////////////
  
  
      /**
       * Construct a new, empty AttributesImpl object.
       */
      public AttributesImpl ()
      {
      length = 0;
      data = null;
      }
  
  
      /**
       * Copy an existing Attributes object.
       *
       * <p>This constructor is especially useful inside a
       * {@link org.xml.sax.ContentHandler#startElement startElement} event.</p>
       *
       * @param atts The existing Attributes object.
       */
      public AttributesImpl (Attributes atts)
      {
      setAttributes(atts);
      }
  
  
  
      ////////////////////////////////////////////////////////////////////
      // Implementation of org.xml.sax.Attributes.
      ////////////////////////////////////////////////////////////////////
  
  
      /**
       * Return the number of attributes in the list.
       *
       * @return The number of attributes in the list.
       * @see org.xml.sax.Attributes#getLength
       */
      public int getLength ()
      {
      return length;
      }
  
  
      /**
       * Return an attribute's Namespace URI.
       *
       * @param index The attribute's index (zero-based).
       * @return The Namespace URI, the empty string if none is
       *         available, or null if the index is out of range.
       * @see org.xml.sax.Attributes#getURI
       */
      public String getURI (int index)
      {
      if (index >= 0 && index < length) {
          return data[index*5];
      } else {
          return null;
      }
      }
  
  
      /**
       * Return an attribute's local name.
       *
       * @param index The attribute's index (zero-based).
       * @return The attribute's local name, the empty string if 
       *         none is available, or null if the index if out of range.
       * @see org.xml.sax.Attributes#getLocalName
       */
      public String getLocalName (int index)
      {
      if (index >= 0 && index < length) {
          return data[index*5+1];
      } else {
          return null;
      }
      }
  
  
      /**
       * Return an attribute's qualified (prefixed) name.
       *
       * @param index The attribute's index (zero-based).
       * @return The attribute's qualified name, the empty string if 
       *         none is available, or null if the index is out of bounds.
       * @see org.xml.sax.Attributes#getQName
       */
      public String getQName (int index)
      {
      if (index >= 0 && index < length) {
          return data[index*5+2];
      } else {
          return null;
      }
      }
  
  
      /**
       * Return an attribute's type by index.
       *
       * @param index The attribute's index (zero-based).
       * @return The attribute's type, "CDATA" if the type is unknown, or null
       *         if the index is out of bounds.
       * @see org.xml.sax.Attributes#getType(int)
       */
      public String getType (int index)
      {
      if (index >= 0 && index < length) {
          return data[index*5+3];
      } else {
          return null;
      }
      }
  
  
      /**
       * Return an attribute's value by index.
       *
       * @param index The attribute's index (zero-based).
       * @return The attribute's value or null if the index is out of bounds.
       * @see org.xml.sax.Attributes#getValue(int)
       */
      public String getValue (int index)
      {
      if (index >= 0 && index < length) {
          return data[index*5+4];
      } else {
          return null;
      }
      }
  
  
      /**
       * Look up an attribute's index by Namespace name.
       *
       * <p>In many cases, it will be more efficient to look up the name once and
       * use the index query methods rather than using the name query methods
       * repeatedly.</p>
       *
       * @param uri The attribute's Namespace URI, or the empty
       *        string if none is available.
       * @param localName The attribute's local name.
       * @return The attribute's index, or -1 if none matches.
       * @see org.xml.sax.Attributes#getIndex(java.lang.String,java.lang.String)
       */
      public int getIndex (String uri, String localName)
      {
      int max = length * 5;
      for (int i = 0; i < max; i += 5) {
          if (data[i].equals(uri) && data[i+1].equals(localName)) {
          return i / 5;
          }
      } 
      return -1;
      }
  
  
      /**
       * Look up an attribute's index by qualified (prefixed) name.
       *
       * @param qName The qualified name.
       * @return The attribute's index, or -1 if none matches.
       * @see org.xml.sax.Attributes#getIndex(java.lang.String)
       */
      public int getIndex (String qName)
      {
      int max = length * 5;
      for (int i = 0; i < max; i += 5) {
          if (data[i+2].equals(qName)) {
          return i / 5;
          }
      } 
      return -1;
      }
  
  
      /**
       * Look up an attribute's type by Namespace-qualified name.
       *
       * @param uri The Namespace URI, or the empty string for a name
       *        with no explicit Namespace URI.
       * @param localName The local name.
       * @return The attribute's type, or null if there is no
       *         matching attribute.
       * @see org.xml.sax.Attributes#getType(java.lang.String,java.lang.String)
       */
      public String getType (String uri, String localName)
      {
      int max = length * 5;
      for (int i = 0; i < max; i += 5) {
          if (data[i].equals(uri) && data[i+1].equals(localName)) {
          return data[i+3];
          }
      } 
      return null;
      }
  
  
      /**
       * Look up an attribute's type by qualified (prefixed) name.
       *
       * @param qName The qualified name.
       * @return The attribute's type, or null if there is no
       *         matching attribute.
       * @see org.xml.sax.Attributes#getType(java.lang.String)
       */
      public String getType (String qName)
      {
      int max = length * 5;
      for (int i = 0; i < max; i += 5) {
          if (data[i+2].equals(qName)) {
          return data[i+3];
          }
      }
      return null;
      }
  
  
      /**
       * Look up an attribute's value by Namespace-qualified name.
       *
       * @param uri The Namespace URI, or the empty string for a name
       *        with no explicit Namespace URI.
       * @param localName The local name.
       * @return The attribute's value, or null if there is no
       *         matching attribute.
       * @see org.xml.sax.Attributes#getValue(java.lang.String,java.lang.String)
       */
      public String getValue (String uri, String localName)
      {
      int max = length * 5;
      for (int i = 0; i < max; i += 5) {
          if (data[i].equals(uri) && data[i+1].equals(localName)) {
          return data[i+4];
          }
      }
      return null;
      }
  
  
      /**
       * Look up an attribute's value by qualified (prefixed) name.
       *
       * @param qName The qualified name.
       * @return The attribute's value, or null if there is no
       *         matching attribute.
       * @see org.xml.sax.Attributes#getValue(java.lang.String)
       */
      public String getValue (String qName)
      {
      int max = length * 5;
      for (int i = 0; i < max; i += 5) {
          if (data[i+2].equals(qName)) {
          return data[i+4];
          }
      }
      return null;
      }
  
  
  
      ////////////////////////////////////////////////////////////////////
      // Manipulators.
      ////////////////////////////////////////////////////////////////////
  
  
      /**
       * Clear the attribute list for reuse.
       *
       * <p>Note that no memory is actually freed by this call:
       * the current arrays are kept so that they can be 
       * reused.</p>
       */
      public void clear ()
      {
      length = 0;
      }
  
  
      /**
       * Copy an entire Attributes object.
       *
       * <p>It may be more efficient to reuse an existing object
       * rather than constantly allocating new ones.</p>
       * 
       * @param atts The attributes to copy.
       */
      public void setAttributes (Attributes atts)
      {
      clear();
      length = atts.getLength();
      data = new String[length*5]; 
      for (int i = 0; i < length; i++) {
          data[i*5] = atts.getURI(i);
          data[i*5+1] = atts.getLocalName(i);
          data[i*5+2] = atts.getQName(i);
          data[i*5+3] = atts.getType(i);
          data[i*5+4] = atts.getValue(i);
      }
      }
  
  
      /**
       * Add an attribute to the end of the list.
       *
       * <p>For the sake of speed, this method does no checking
       * to see if the attribute is already in the list: that is
       * the responsibility of the application.</p>
       *
       * @param uri The Namespace URI, or the empty string if
       *        none is available or Namespace processing is not
       *        being performed.
       * @param localName The local name, or the empty string if
       *        Namespace processing is not being performed.
       * @param qName The qualified (prefixed) name, or the empty string
       *        if qualified names are not available.
       * @param type The attribute type as a string.
       * @param value The attribute value.
       */
      public void addAttribute (String uri, String localName, String qName,
                    String type, String value)
      {
      ensureCapacity(length+1);
      data[length*5] = uri;
      data[length*5+1] = localName;
      data[length*5+2] = qName;
      data[length*5+3] = type;
      data[length*5+4] = value;
      length++;
      }
  
  
      /**
       * Set an attribute in the list.
       *
       * <p>For the sake of speed, this method does no checking
       * for name conflicts or well-formedness: such checks are the
       * responsibility of the application.</p>
       *
       * @param index The index of the attribute (zero-based).
       * @param uri The Namespace URI, or the empty string if
       *        none is available or Namespace processing is not
       *        being performed.
       * @param localName The local name, or the empty string if
       *        Namespace processing is not being performed.
       * @param qName The qualified name, or the empty string
       *        if qualified names are not available.
       * @param type The attribute type as a string.
       * @param value The attribute value.
       * @exception java.lang.ArrayIndexOutOfBoundsException When the
       *            supplied index does not point to an attribute
       *            in the list.
       */
      public void setAttribute (int index, String uri, String localName,
                    String qName, String type, String value)
      {
      if (index >= 0 && index < length) {
          data[index*5] = uri;
          data[index*5+1] = localName;
          data[index*5+2] = qName;
          data[index*5+3] = type;
          data[index*5+4] = value;
      } else {
          badIndex(index);
      }
      }
  
  
      /**
       * Remove an attribute from the list.
       *
       * @param index The index of the attribute (zero-based).
       * @exception java.lang.ArrayIndexOutOfBoundsException When the
       *            supplied index does not point to an attribute
       *            in the list.
       */
      public void removeAttribute (int index)
      {
          if (index >= 0 && index < length) {
              if (index < length - 1) {
                  System.arraycopy(data, (index+1)*5, data, index*5,
                           (length-index-1)*5);
              }
              length--;
          } else {
              badIndex(index);
          }
      }
  
  
      /**
       * Set the Namespace URI of a specific attribute.
       *
       * @param index The index of the attribute (zero-based).
       * @param uri The attribute's Namespace URI, or the empty
       *        string for none.
       * @exception java.lang.ArrayIndexOutOfBoundsException When the
       *            supplied index does not point to an attribute
       *            in the list.
       */
      public void setURI (int index, String uri)
      {
      if (index >= 0 && index < length) {
          data[index*5] = uri;
      } else {
          badIndex(index);
      }
      }
  
  
      /**
       * Set the local name of a specific attribute.
       *
       * @param index The index of the attribute (zero-based).
       * @param localName The attribute's local name, or the empty
       *        string for none.
       * @exception java.lang.ArrayIndexOutOfBoundsException When the
       *            supplied index does not point to an attribute
       *            in the list.
       */
      public void setLocalName (int index, String localName)
      {
      if (index >= 0 && index < length) {
          data[index*5+1] = localName;
      } else {
          badIndex(index);
      }
      }
  
  
      /**
       * Set the qualified name of a specific attribute.
       *
       * @param index The index of the attribute (zero-based).
       * @param qName The attribute's qualified name, or the empty
       *        string for none.
       * @exception java.lang.ArrayIndexOutOfBoundsException When the
       *            supplied index does not point to an attribute
       *            in the list.
       */
      public void setQName (int index, String qName)
      {
      if (index >= 0 && index < length) {
          data[index*5+2] = qName;
      } else {
          badIndex(index);
      }
      }
  
  
      /**
       * Set the type of a specific attribute.
       *
       * @param index The index of the attribute (zero-based).
       * @param type The attribute's type.
       * @exception java.lang.ArrayIndexOutOfBoundsException When the
       *            supplied index does not point to an attribute
       *            in the list.
       */
      public void setType (int index, String type)
      {
      if (index >= 0 && index < length) {
          data[index*5+3] = type;
      } else {
          badIndex(index);
      }
      }
  
  
      /**
       * Set the value of a specific attribute.
       *
       * @param index The index of the attribute (zero-based).
       * @param value The attribute's value.
       * @exception java.lang.ArrayIndexOutOfBoundsException When the
       *            supplied index does not point to an attribute
       *            in the list.
       */
      public void setValue (int index, String value)
      {
      if (index >= 0 && index < length) {
          data[index*5+4] = value;
      } else {
          badIndex(index);
      }
      }
  
  
  
      ////////////////////////////////////////////////////////////////////
      // Internal methods.
      ////////////////////////////////////////////////////////////////////
  
  
      /**
       * Ensure the internal array's capacity.
       *
       * @param n The minimum number of attributes that the array must
       *        be able to hold.
       */
      private void ensureCapacity (int n)
      {
      if (n > 0 && (data == null || data.length==0)) {
          data = new String[25];
      }
  
      int max = data.length;
      if (max >= n * 5) {
          return;
      }
  
  
      while (max < n * 5) {
          max *= 2;
      }
      String newData[] = new String[max];
      System.arraycopy(data, 0, newData, 0, length*5);
      data = newData;
      }
  
  
      /**
       * Report a bad array index in a manipulator.
       *
       * @param index The index to report.
       * @exception java.lang.ArrayIndexOutOfBoundsException Always.
       */
      private void badIndex (int index)
      throws ArrayIndexOutOfBoundsException
      {
      String msg =
          "Attempt to modify attribute at illegal index: " + index;
      throw new ArrayIndexOutOfBoundsException(msg);
      }
  
  
  
      ////////////////////////////////////////////////////////////////////
      // Internal state.
      ////////////////////////////////////////////////////////////////////
  
      int length;
      String data [];
  
  }
  
  // end of AttributesImpl.java
  
  