code: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements. See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership. The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the  "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  /*
   * $Id$
   */
  
  package org.apache.xalan.xsltc.runtime;
  
  import org.xml.sax.SAXException;
  
  import org.apache.xml.serializer.EmptySerializer;
  
  /**
   * @author Jacek Ambroziak
   * @author Santiago Pericas-Geertsen
   * @author Morten Jorgensen
   */
  public final class StringValueHandler extends EmptySerializer {
  
      private StringBuffer _buffer = new StringBuffer();
      private String _str = null;
      private static final String EMPTY_STR = "";
      private boolean m_escaping = false;
      private int _nestedLevel = 0;
  	
      public void characters(char[] ch, int off, int len) 
  	throws SAXException 
      {
  	if (_nestedLevel > 0)
  	    return;
  	
  	if (_str != null) {
  	    _buffer.append(_str);
  	    _str = null;
  	}
  	_buffer.append(ch, off, len);
      }
  
      public String getValue() {
  	if (_buffer.length() != 0) {
  	    String result = _buffer.toString();
  	    _buffer.setLength(0);
  	    return result;
  	}
  	else {
  	    String result = _str;
  	    _str = null;
  	    return (result != null) ? result : EMPTY_STR;
  	}
      }
  
      public void characters(String characters) throws SAXException {
  	if (_nestedLevel > 0)
  	    return;
  
  	if (_str == null && _buffer.length() == 0) {
  	    _str = characters;
  	}
  	else {
  	    if (_str != null) {
  	        _buffer.append(_str);
  	        _str = null;
  	    }
  	    
  	    _buffer.append(characters);
  	}
      }
      
      public void startElement(String qname) throws SAXException {
          _nestedLevel++;
      }
  
      public void endElement(String qname) throws SAXException {
          _nestedLevel--;
      }
  
      // Override the setEscaping method just to indicate that this class is
      // aware that that method might be called.
      public boolean setEscaping(boolean bool) {
          boolean oldEscaping = m_escaping;
          m_escaping = bool;
  
          return bool;
      }
  
      /**
       * The value of a PI must not contain the substring "?>". Should
       * that substring be present, replace it by "? >". 
       */
      public String getValueOfPI() {
  	final String value = getValue();
  
  	if (value.indexOf("?>") > 0) {
  	    final int n = value.length(); 
  	    final StringBuffer valueOfPI = new StringBuffer();
  
  	    for (int i = 0; i < n;) {
  		final char ch = value.charAt(i++);
  		if (ch == '?' && value.charAt(i) == '>') {
  		    valueOfPI.append("? >"); i++;
  		}
  		else {
  		    valueOfPI.append(ch);
  		}
  	    } 
  	    return valueOfPI.toString();
  	}
  	return value;
      }
  }
  