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.trace;
  
  import java.lang.reflect.Method;
  import java.util.TooManyListenersException;
  import java.util.Vector;
  
  import org.apache.xalan.templates.ElemTemplateElement;
  import org.apache.xalan.transformer.TransformerImpl;
  import org.apache.xpath.XPath;
  import org.apache.xpath.objects.XObject;
  import org.w3c.dom.Node;
  
  /**
   * This class manages trace listeners, and acts as an
   * interface for the tracing functionality in Xalan.
   */
  public class TraceManager
  {
  
    /** A transformer instance */
    private TransformerImpl m_transformer;
  
    /**
     * Constructor for the trace manager.
     *
     * @param transformer a non-null instance of a transformer
     */
    public TraceManager(TransformerImpl transformer)
    {
      m_transformer = transformer;
    }
  
    /**
     * List of listeners who are interested in tracing what's
     * being generated.
     */
    private Vector m_traceListeners = null;
  
    /**
     * Add a trace listener for the purposes of debugging and diagnosis.
     * @param tl Trace listener to be added.
     *
     * @throws TooManyListenersException
     */
    public void addTraceListener(TraceListener tl)
            throws TooManyListenersException
    {
  
      m_transformer.setDebug(true);
  
      if (null == m_traceListeners)
        m_traceListeners = new Vector();
  
      m_traceListeners.addElement(tl);
    }
  
    /**
     * Remove a trace listener.
     * @param tl Trace listener to be removed.
     */
    public void removeTraceListener(TraceListener tl)
    {
  
      if (null != m_traceListeners)
      {
        m_traceListeners.removeElement(tl);
        
        // The following line added to fix the bug#5140: hasTraceListeners() returns true
        // after adding and removing a listener.
        // Check: if m_traceListeners is empty, then set it to NULL.
        if (0 == m_traceListeners.size()) m_traceListeners = null;
      }
    }
  
    /**
     * Fire a generate event.
     *
     * @param te Generate Event to fire
     */
    public void fireGenerateEvent(GenerateEvent te)
    {
  
      if (null != m_traceListeners)
      {
        int nListeners = m_traceListeners.size();
  
        for (int i = 0; i < nListeners; i++)
        {
          TraceListener tl = (TraceListener) m_traceListeners.elementAt(i);
  
          tl.generated(te);
        }
      }
    }
  
    /**
     * Tell if trace listeners are present.
     *
     * @return True if there are trace listeners
     */
    public boolean hasTraceListeners()
    {
      return (null != m_traceListeners);
    }
  
    /**
     * Fire a trace event.
     *
     * @param styleNode Stylesheet template node
     */
    public void fireTraceEvent(ElemTemplateElement styleNode)
    {
  
      if (hasTraceListeners())
      {
        int sourceNode = m_transformer.getXPathContext().getCurrentNode();
        Node source = getDOMNodeFromDTM(sourceNode);
  
        fireTraceEvent(new TracerEvent(m_transformer, source, 
                       m_transformer.getMode(),  /*sourceNode, mode,*/
                                       styleNode));
      }
    }
  
    /**
     * Fire a end trace event, after all children of an element have been
     * executed.
     *
     * @param styleNode Stylesheet template node
     */
    public void fireTraceEndEvent(ElemTemplateElement styleNode)
    {
  
      if (hasTraceListeners())
      {
        int sourceNode = m_transformer.getXPathContext().getCurrentNode();
        Node source = getDOMNodeFromDTM(sourceNode);
  
        fireTraceEndEvent(new TracerEvent(m_transformer, source,
                       m_transformer.getMode(),  /*sourceNode, mode,*/
                                       styleNode));
      }
    }
  
    /**
     * Fire a trace event.
     *
     * @param te Trace event to fire
     */
    public void fireTraceEndEvent(TracerEvent te)
    {
  
      if (hasTraceListeners())
      {
        int nListeners = m_traceListeners.size();
  
        for (int i = 0; i < nListeners; i++)
        {
          TraceListener tl = (TraceListener) m_traceListeners.elementAt(i);
          if(tl instanceof TraceListenerEx2)
          {
            ((TraceListenerEx2)tl).traceEnd(te);
          }
        }
      }
    }
  
  
  
    /**
     * Fire a trace event.
     *
     * @param te Trace event to fire
     */
    public void fireTraceEvent(TracerEvent te)
    {
  
      if (hasTraceListeners())
      {
        int nListeners = m_traceListeners.size();
  
        for (int i = 0; i < nListeners; i++)
        {
          TraceListener tl = (TraceListener) m_traceListeners.elementAt(i);
  
          tl.trace(te);
        }
      }
    }
  
    /**
     * Fire a selection event.
     *
     * @param sourceNode Current source node
     * @param styleNode node in the style tree reference for the event.
     * @param attributeName The attribute name from which the selection is made.
     * @param xpath The XPath that executed the selection.
     * @param selection The result of the selection.
     *
     * @throws javax.xml.transform.TransformerException
     */
    public void fireSelectedEvent(
            int sourceNode, ElemTemplateElement styleNode, String attributeName, 
            XPath xpath, XObject selection)
              throws javax.xml.transform.TransformerException
    {
  
      if (hasTraceListeners())
      {
        Node source = getDOMNodeFromDTM(sourceNode);
          
        fireSelectedEvent(new SelectionEvent(m_transformer, source, styleNode,
                                             attributeName, xpath, selection));
      }
    }
    
    /**
     * Fire a selection event.
     *
     * @param sourceNode Current source node
     * @param styleNode node in the style tree reference for the event.
     * @param attributeName The attribute name from which the selection is made.
     * @param xpath The XPath that executed the selection.
     * @param selection The result of the selection.
     *
     * @throws javax.xml.transform.TransformerException
     */
    public void fireSelectedEndEvent(
            int sourceNode, ElemTemplateElement styleNode, String attributeName, 
            XPath xpath, XObject selection)
              throws javax.xml.transform.TransformerException
    {
  
      if (hasTraceListeners())
      {
        Node source = getDOMNodeFromDTM(sourceNode);
          
        fireSelectedEndEvent(new EndSelectionEvent(m_transformer, source, styleNode,
                                             attributeName, xpath, selection));
      }
    }
    
    /**
     * Fire a selection event.
     *
     * @param se Selection event to fire
     *
     * @throws javax.xml.transform.TransformerException
     */
    public void fireSelectedEndEvent(EndSelectionEvent se)
            throws javax.xml.transform.TransformerException
    {
  
      if (hasTraceListeners())
      {
        int nListeners = m_traceListeners.size();
  
        for (int i = 0; i < nListeners; i++)
        {
          TraceListener tl = (TraceListener) m_traceListeners.elementAt(i);
  
          if(tl instanceof TraceListenerEx)
            ((TraceListenerEx)tl).selectEnd(se);
        }
      }
    }
  
    /**
     * Fire a selection event.
     *
     * @param se Selection event to fire
     *
     * @throws javax.xml.transform.TransformerException
     */
    public void fireSelectedEvent(SelectionEvent se)
            throws javax.xml.transform.TransformerException
    {
  
      if (hasTraceListeners())
      {
        int nListeners = m_traceListeners.size();
  
        for (int i = 0; i < nListeners; i++)
        {
          TraceListener tl = (TraceListener) m_traceListeners.elementAt(i);
  
          tl.selected(se);
        }
      }
    }
    
  
    /**
     * Fire an end extension event.
     *
     * @see java.lang.reflect.Method#invoke
     * 
     * @param method The java method about to be executed
     * @param instance The instance the method will be executed on
     * @param arguments Parameters passed to the method.
     */
    public void fireExtensionEndEvent(Method method, Object instance, Object[] arguments)
    {
        ExtensionEvent ee = new ExtensionEvent(m_transformer, method, instance, arguments);
  
      if (hasTraceListeners())
      {
        int nListeners = m_traceListeners.size();
  
        for (int i = 0; i < nListeners; i++)
        {
          TraceListener tl = (TraceListener) m_traceListeners.elementAt(i);
          if(tl instanceof TraceListenerEx3)
          {
            ((TraceListenerEx3)tl).extensionEnd(ee);
          }
        }
      }
    }
  
    /**
     * Fire an end extension event.
     *
     * @see java.lang.reflect.Method#invoke
     * 
     * @param method The java method about to be executed
     * @param instance The instance the method will be executed on
     * @param arguments Parameters passed to the method.
     */
    public void fireExtensionEvent(Method method, Object instance, Object[] arguments)
    {
      ExtensionEvent ee = new ExtensionEvent(m_transformer, method, instance, arguments);
  
      if (hasTraceListeners())
      {
        int nListeners = m_traceListeners.size();
  
        for (int i = 0; i < nListeners; i++)
        {
          TraceListener tl = (TraceListener) m_traceListeners.elementAt(i);
          if(tl instanceof TraceListenerEx3)
          {
            ((TraceListenerEx3)tl).extension(ee);
          }
        }
      }
    }
  
    /**
     * Fire an end extension event.
     *
     * @see java.lang.reflect.Method#invoke
     * 
     * @param ee the ExtensionEvent to fire
     */
    public void fireExtensionEndEvent(ExtensionEvent ee)
    {
      if (hasTraceListeners())
      {
        int nListeners = m_traceListeners.size();
  
        for (int i = 0; i < nListeners; i++)
        {
          TraceListener tl = (TraceListener) m_traceListeners.elementAt(i);
          if(tl instanceof TraceListenerEx3)
          {
            ((TraceListenerEx3)tl).extensionEnd(ee);
          }
        }
      }
    }
  
    /**
     * Fire an end extension event.
     *
     * @see java.lang.reflect.Method#invoke
     * 
     * @param ee the ExtensionEvent to fire
     */
    public void fireExtensionEvent(ExtensionEvent ee)
    {    
        
      if (hasTraceListeners())
      {
        int nListeners = m_traceListeners.size();
  
        for (int i = 0; i < nListeners; i++)
        {
          TraceListener tl = (TraceListener) m_traceListeners.elementAt(i);
          if(tl instanceof TraceListenerEx3)
          {
            ((TraceListenerEx3)tl).extension(ee);
          }
        }
      }
    }
    
    /**
     * Get the DOM Node of the current XPath context, which is possibly null.
     * @param sourceNode the handle on the node used by a DTM.
     */
    private Node getDOMNodeFromDTM(int sourceNode) {
      org.apache.xml.dtm.DTM dtm = m_transformer.getXPathContext().getDTM(sourceNode);
      final Node source = (dtm == null) ? null : dtm.getNode(sourceNode);
      return source;
    }
  }
  