content: /*
   * $Header$
   * $Revision$
   * $Date$
   *
   * ====================================================================
   *
   * Copyright 2000-2002 bob mcwhirter & James Strachan.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met:
   * 
   *   * Redistributions of source code must retain the above copyright
   *     notice, this list of conditions and the following disclaimer.
   * 
   *   * 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.
   * 
   *   * Neither the name of the Jaxen Project nor the names of its
   *     contributors may be used to endorse or promote products derived 
   *     from this software without specific prior written permission.
   * 
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
   * IS" AND ANY EXPRESS 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 THE COPYRIGHT OWNER
   * OR 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 the Jaxen Project and was originally 
   * created by bob mcwhirter <bob@werken.com> and 
   * James Strachan <jstrachan@apache.org>.  For more information on the 
   * Jaxen Project, please see <http://www.jaxen.org/>.
   * 
   * $Id$
   */
  
  
  package org.jaxen.pattern;
  
  import java.util.LinkedList;
  
  import org.jaxen.JaxenException;
  import org.jaxen.JaxenHandler;
  import org.jaxen.expr.Expr;
  import org.jaxen.expr.FilterExpr;
  import org.jaxen.saxpath.Axis;
  
  /** SAXPath <code>XPathHandler</code> implementation capable
   *  of building Jaxen expression trees which can walk various
   *  different object models.
   *
   *  @author bob mcwhirter (bob@werken.com)
   */
  public class PatternHandler extends JaxenHandler
  {
      private Pattern pattern;
      
      public PatternHandler()
      {
      }
      
      /** Retrieve the simplified Jaxen Pattern expression tree.
       *
       *  <p>
       *  This method is only valid once <code>XPathReader.parse(...)</code>
       *  successfully returned.
       *  </p>
       *
       *  @return The Pattern expression tree.
       */
      public Pattern getPattern()
      {
          return getPattern( true );
      }
  
      /** Retrieve the Jaxen Pattern expression tree, optionally
       *  simplified.
       *
       *  <p>
       *  This method is only valid once <code>XPathReader.parse(...)</code>
       *  successfully returned.
       *  </p>
       *  
       *  @param shouldSimplify ????
       *
       *  @return The Pattern expression tree.
       */
      public Pattern getPattern(boolean shouldSimplify)
      {
          if ( shouldSimplify && ! this.simplified )
          {
              //System.err.println("simplifying....");
              this.pattern.simplify();
              this.simplified = true;
          }
  
          return this.pattern;
      }
  
      
      
      
      public void endXPath()
      {
          this.pattern = (Pattern) pop();
  
          System.out.println( "stack is: " + stack );
          
          popFrame();
      }
  
      public void endPathExpr()
      {
          //System.err.println("endPathExpr()");
  
          // PathExpr ::=   LocationPath
          //              | FilterExpr
          //              | FilterExpr / RelativeLocationPath
          //              | FilterExpr // RelativeLocationPath
          //
          // If the current stack-frame has two items, it's a
          // FilterExpr and a LocationPath (of some flavor).
          //
          // If the current stack-frame has one item, it's simply
          // a FilterExpr, and more than like boils down to a
          // primary expr of some flavor.  But that's for another
          // method...
  
          LinkedList frame = popFrame();
          
          System.out.println( "endPathExpr(): " + frame );
              
          push( frame.removeFirst() );
  /*        
          LocationPathPattern locationPath = new LocationPathPattern();
          push( locationPath );
          while (! frame.isEmpty() )
          {
              Object filter = frame.removeLast();
              if ( filter instanceof NodeTest ) 
              {
                  locationPath.setNodeTest( (NodeTest) filter );
              }
              else if ( filter instanceof FilterExpr )
              {
                  locationPath.addFilter( (FilterExpr) filter );
              }
              else if ( filter instanceof LocationPathPattern ) 
              {
                  LocationPathPattern parent = (LocationPathPattern) filter;
                  locationPath.setParentPattern( parent );
                  locationPath = parent;
              }
              else if ( filter != null ) 
              {
                  throw new JaxenException( "Unknown filter: " + filter );
              }
          }
  */
      }
  
      public void startAbsoluteLocationPath()
      {
          //System.err.println("startAbsoluteLocationPath()");
          pushFrame();
  
          push( createAbsoluteLocationPath() );
      }
      
      public void endAbsoluteLocationPath() throws JaxenException
      {
          //System.err.println("endAbsoluteLocationPath()");
          endLocationPath();
      }
  
      public void startRelativeLocationPath()
      {
          //System.err.println("startRelativeLocationPath()");
          pushFrame();
  
          push( createRelativeLocationPath() );
      }
  
      public void endRelativeLocationPath() throws JaxenException
      {
          //System.err.println("endRelativeLocationPath()");
          endLocationPath();
      }
  
      protected void endLocationPath() throws JaxenException
      {
          // start at the back, its the main pattern then add everything else as 
          LinkedList list = popFrame();
          
          System.out.println( "endLocationPath: " + list );
  
          LocationPathPattern locationPath = (LocationPathPattern) list.removeFirst();
          push( locationPath );
          boolean doneNodeTest = false;
          while ( ! list.isEmpty() )
          {
              Object filter = list.removeFirst();
              if ( filter instanceof NodeTest ) 
              {
                  if ( doneNodeTest ) 
                  {
                      LocationPathPattern parent = new LocationPathPattern( (NodeTest) filter );
                      locationPath.setParentPattern( parent );
                      locationPath = parent;
                      doneNodeTest = false;
                  }   
                  else
                  {
                      locationPath.setNodeTest( (NodeTest) filter );
                  }
              }
              else if ( filter instanceof FilterExpr )
              {
                  locationPath.addFilter( (FilterExpr) filter );
              }
              else if ( filter instanceof LocationPathPattern ) 
              {
                  LocationPathPattern parent = (LocationPathPattern) filter;
                  locationPath.setParentPattern( parent );
                  locationPath = parent;
                  doneNodeTest = false;
              }
          }
      }
  
      
      public void startNameStep(int axis,
                                String prefix,
                                String localName)
      {
          //System.err.println("startNameStep(" + axis + ", " + prefix + ", " + localName + ")");
          pushFrame();
  
          short nodeType = Pattern.ELEMENT_NODE;            
          switch ( axis ) 
          {
              case Axis.ATTRIBUTE:
                  nodeType = Pattern.ATTRIBUTE_NODE;
                  break;
              case Axis.NAMESPACE:
                  nodeType = Pattern.NAMESPACE_NODE;
                  break;
          }
          
          if ( prefix != null && prefix.length() > 0 && ! prefix.equals( "*" ) ) 
          {                    
              push( new NamespaceTest( prefix, nodeType ) );
          }
          if ( localName != null && localName.length() > 0 && ! localName.equals( "*" ) ) 
          {
              push( new NameTest( localName, nodeType ) );
          }
      }
  
      public void startTextNodeStep(int axis)
      {
          //System.err.println("startTextNodeStep()");
          pushFrame();
          
          push( new NodeTypeTest( Pattern.TEXT_NODE ) );
      }
      
      public void startCommentNodeStep(int axis)
      {
          //System.err.println("startCommentNodeStep()");
          pushFrame();
  
          push( new NodeTypeTest( Pattern.COMMENT_NODE ) );
      }
  
      public void startAllNodeStep(int axis)
      {
          //System.err.println("startAllNodeStep()");
          pushFrame();
  
          push( AnyNodeTest.getInstance() );
      }
  
      public void startProcessingInstructionNodeStep(int axis,
                                                     String name)
      {
          //System.err.println("startProcessingInstructionStep()");
          pushFrame();
  
          // XXXX: should we throw an exception if name is present?            
          push( new NodeTypeTest( Pattern.PROCESSING_INSTRUCTION_NODE ) );
      }
      
      protected void endStep()
      {
          LinkedList list = popFrame();
          if ( ! list.isEmpty() ) 
          {
              push( list.removeFirst() );
              
              if ( ! list.isEmpty() )
              {
                  System.out.println( "List should now be empty!" + list );
              }
          }
      }
      
  
      public void startUnionExpr()
      {
          //System.err.println("startUnionExpr()");
      }
  
      public void endUnionExpr(boolean create) throws JaxenException
      {
          //System.err.println("endUnionExpr()");
  
          if ( create )
          {
              //System.err.println("makeUnionExpr");
  
              Expr rhs = (Expr) pop();
              Expr lhs = (Expr) pop();
  
              push( getXPathFactory().createUnionExpr( lhs,
                                                      rhs ) );
          }
      }
  
      protected Pattern createAbsoluteLocationPath() 
      {
          return new LocationPathPattern( NodeTypeTest.DOCUMENT_TEST );
      }
  
      protected Pattern createRelativeLocationPath() 
      {
          return new LocationPathPattern();
      }
  
  }
  