walkerfactory.java

java1.6众多例子参考

          if(Axis.PRECEDING == pat.getAxis())
            pat.setAxis(Axis.PRECEDINGANDANCESTOR);
            
          else if(Axis.DESCENDANT == pat.getAxis())
            pat.setAxis(Axis.DESCENDANTORSELF);
          
          pat = attrPat;
        }
        else if(Axis.CHILD == pat.getAxis())
        {
          // In this case just change the axis.
          // pat.setWhatToShow(whatToShow);
          pat.setAxis(Axis.ATTRIBUTE);
        }
      }
      axis = nextAxis;
      //paxis = nextPaxis;
      tail = pat;
    }
    
    if(axis < Axis.ALL)
    {
      StepPattern selfPattern = new ContextMatchStepPattern(axis, paxis);
      // We need to keep the new nodetest from affecting the score...
      XNumber score = tail.getStaticScore();
      tail.setRelativePathPattern(selfPattern);
      tail.setStaticScore(score);
      selfPattern.setStaticScore(score);
    }        

    if (DEBUG_PATTERN_CREATION)
    {
      System.out.println("Done loading steps: "+step.toString());
            
      System.out.println("");
    }
    return step;  // start from last pattern?? //firstStep;
  }

  /**
   * Create a StepPattern that is contained within a LocationPath.
   *
   *
   * @param compiler The compiler that holds the syntax tree/op map to
   * construct from.
   * @param stepOpCodePos The current op code position within the opmap.
   * @param mpi The MatchPatternIterator to which the steps will be attached.
   * @param analysis 32 bits of analysis, from which the type of AxesWalker
   *                 may be influenced.
   * @param tail The step that is the first step analyzed, but the last 
   *                  step in the relative match linked list, i.e. the tail.
   *                  May be null.
   * @param head The step that is the current head of the relative 
   *                 match step linked list.
   *                 May be null.
   *
   * @return the head of the list.
   *
   * @throws javax.xml.transform.TransformerException
   */
  private static StepPattern createDefaultStepPattern(
          Compiler compiler, int opPos, MatchPatternIterator mpi, 
          int analysis, StepPattern tail, StepPattern head)
            throws javax.xml.transform.TransformerException
  {

    int stepType = compiler.getOp(opPos);
    boolean simpleInit = false;
    int totalNumberWalkers = (analysis & BITS_COUNT);
    boolean prevIsOneStepDown = true;
    int firstStepPos = compiler.getFirstChildPos(opPos);
    
    int whatToShow = compiler.getWhatToShow(opPos);
    StepPattern ai = null;
    int axis, predicateAxis;
    
    switch (stepType)
    {
    case OpCodes.OP_VARIABLE :
    case OpCodes.OP_EXTFUNCTION :
    case OpCodes.OP_FUNCTION :
    case OpCodes.OP_GROUP :
      prevIsOneStepDown = false;

      Expression expr;

      switch (stepType)
      {
      case OpCodes.OP_VARIABLE :
      case OpCodes.OP_EXTFUNCTION :
      case OpCodes.OP_FUNCTION :
      case OpCodes.OP_GROUP :
        expr = compiler.compile(opPos);
        break;
      default :
        expr = compiler.compile(opPos + 2);
      }

      axis = Axis.FILTEREDLIST;
      predicateAxis = Axis.FILTEREDLIST;
      ai = new FunctionPattern(expr, axis, predicateAxis);
      simpleInit = true;
      break;
    case OpCodes.FROM_ROOT :
      whatToShow = DTMFilter.SHOW_DOCUMENT
                   | DTMFilter.SHOW_DOCUMENT_FRAGMENT;

      axis = Axis.ROOT;
      predicateAxis = Axis.ROOT;
      ai = new StepPattern(DTMFilter.SHOW_DOCUMENT | 
                                DTMFilter.SHOW_DOCUMENT_FRAGMENT,
                                axis, predicateAxis);
      break;
    case OpCodes.FROM_ATTRIBUTES :
      whatToShow = DTMFilter.SHOW_ATTRIBUTE;
      axis = Axis.PARENT;
      predicateAxis = Axis.ATTRIBUTE;
      // ai = new StepPattern(whatToShow, Axis.SELF, Axis.SELF);
      break;
    case OpCodes.FROM_NAMESPACE :
      whatToShow = DTMFilter.SHOW_NAMESPACE;
      axis = Axis.PARENT;
      predicateAxis = Axis.NAMESPACE;
      // ai = new StepPattern(whatToShow, axis, predicateAxis);
      break;
    case OpCodes.FROM_ANCESTORS :
      axis = Axis.DESCENDANT;
      predicateAxis = Axis.ANCESTOR;
      break;
    case OpCodes.FROM_CHILDREN :
      axis = Axis.PARENT;
      predicateAxis = Axis.CHILD;
      break;
    case OpCodes.FROM_ANCESTORS_OR_SELF :
      axis = Axis.DESCENDANTORSELF;
      predicateAxis = Axis.ANCESTORORSELF;
      break;
    case OpCodes.FROM_SELF :
      axis = Axis.SELF;
      predicateAxis = Axis.SELF;
      break;
    case OpCodes.FROM_PARENT :
      axis = Axis.CHILD;
      predicateAxis = Axis.PARENT;
      break;
    case OpCodes.FROM_PRECEDING_SIBLINGS :
      axis = Axis.FOLLOWINGSIBLING;
      predicateAxis = Axis.PRECEDINGSIBLING;
      break;
    case OpCodes.FROM_PRECEDING :
      axis = Axis.FOLLOWING;
      predicateAxis = Axis.PRECEDING;
      break;
    case OpCodes.FROM_FOLLOWING_SIBLINGS :
      axis = Axis.PRECEDINGSIBLING;
      predicateAxis = Axis.FOLLOWINGSIBLING;
      break;
    case OpCodes.FROM_FOLLOWING :
      axis = Axis.PRECEDING;
      predicateAxis = Axis.FOLLOWING;
      break;
    case OpCodes.FROM_DESCENDANTS_OR_SELF :
      axis = Axis.ANCESTORORSELF;
      predicateAxis = Axis.DESCENDANTORSELF;
      break;
    case OpCodes.FROM_DESCENDANTS :
      axis = Axis.ANCESTOR;
      predicateAxis = Axis.DESCENDANT;
      break;
    default :
      throw new RuntimeException(XSLMessages.createXPATHMessage(XPATHErrorResources.ER_NULL_ERROR_HANDLER, new Object[]{Integer.toString(stepType)})); //"Programmer's assertion: unknown opcode: "
                                 //+ stepType);
    }
    if(null == ai)
    {
      whatToShow = compiler.getWhatToShow(opPos); // %REVIEW%
      ai = new StepPattern(whatToShow, compiler.getStepNS(opPos),
                                compiler.getStepLocalName(opPos),
                                axis, predicateAxis);
    }
   
    if (false || DEBUG_PATTERN_CREATION)
    {
      System.out.print("new step: "+ ai);
      System.out.print(", axis: " + Axis.getNames(ai.getAxis()));
      System.out.print(", predAxis: " + Axis.getNames(ai.getAxis()));
      System.out.print(", what: ");
      System.out.print("    ");
      ai.debugWhatToShow(ai.getWhatToShow());
    }

    int argLen = compiler.getFirstPredicateOpPos(opPos);

    ai.setPredicates(compiler.getCompiledPredicates(argLen));

    return ai;
  }

  /**
   * Analyze a step and give information about it's predicates.  Right now this
   * just returns true or false if the step has a predicate.
   *
   * @param compiler non-null reference to compiler object that has processed
   *                 the XPath operations into an opcode map.
   * @param opPos The opcode position for the step.
   * @param stepType The type of step, one of OP_GROUP, etc.
   *
   * @return true if step has a predicate.
   *
   * @throws javax.xml.transform.TransformerException
   */
  static boolean analyzePredicate(Compiler compiler, int opPos, int stepType)
          throws javax.xml.transform.TransformerException
  {

    int argLen;

    switch (stepType)
    {
    case OpCodes.OP_VARIABLE :
    case OpCodes.OP_EXTFUNCTION :
    case OpCodes.OP_FUNCTION :
    case OpCodes.OP_GROUP :
      argLen = compiler.getArgLength(opPos);
      break;
    default :
      argLen = compiler.getArgLengthOfStep(opPos);
    }

    int pos = compiler.getFirstPredicateOpPos(opPos);
    int nPredicates = compiler.countPredicates(pos);

    return (nPredicates > 0) ? true : false;
  }

  /**
   * Create the proper Walker from the axes type.
   *
   * @param compiler non-null reference to compiler object that has processed
   *                 the XPath operations into an opcode map.
   * @param opPos The opcode position for the step.
   * @param lpi The owning location path iterator.
   * @param analysis 32 bits of analysis, from which the type of AxesWalker
   *                 may be influenced.
   *
   * @return non-null reference to AxesWalker derivative.
   * @throws RuntimeException if the input is bad.
   */
  private static AxesWalker createDefaultWalker(Compiler compiler, int opPos,
          WalkingIterator lpi, int analysis)
  {

    AxesWalker ai = null;
    int stepType = compiler.getOp(opPos);

    /*
    System.out.println("0: "+compiler.getOp(opPos));
    System.out.println("1: "+compiler.getOp(opPos+1));
    System.out.println("2: "+compiler.getOp(opPos+2));
    System.out.println("3: "+compiler.getOp(opPos+3));
    System.out.println("4: "+compiler.getOp(opPos+4));
    System.out.println("5: "+compiler.getOp(opPos+5));
    */
    boolean simpleInit = false;
    int totalNumberWalkers = (analysis & BITS_COUNT);
    boolean prevIsOneStepDown = true;

    switch (stepType)
    {
    case OpCodes.OP_VARIABLE :
    case OpCodes.OP_EXTFUNCTION :
    case OpCodes.OP_FUNCTION :
    case OpCodes.OP_GROUP :
      prevIsOneStepDown = false;

      if (DEBUG_WALKER_CREATION)
        System.out.println("new walker:  FilterExprWalker: " + analysis
                           + ", " + compiler.toString());

      ai = new FilterExprWalker(lpi);
      simpleInit = true;
      break;
    case OpCodes.FROM_ROOT :
      ai = new AxesWalker(lpi, Axis.ROOT);
      break;
    case OpCodes.FROM_ANCESTORS :
      prevIsOneStepDown = false;
      ai = new ReverseAxesWalker(lpi, Axis.ANCESTOR);
      break;
    case OpCodes.FROM_ANCESTORS_OR_SELF :
      prevIsOneStepDown = false;
      ai = new ReverseAxesWalker(lpi, Axis.ANCESTORORSELF);
      break;
    case OpCodes.FROM_ATTRIBUTES :
      ai = new AxesWalker(lpi, Axis.ATTRIBUTE);
      break;
    case OpCodes.FROM_NAMESPACE :
      ai = new AxesWalker(lpi, Axis.NAMESPACE);
      break;
    case OpCodes.FROM_CHILDREN :
      ai = new AxesWalker(lpi, Axis.CHILD);
      break;
    case OpCodes.FROM_DESCENDANTS :
      prevIsOneStepDown = false;
      ai = new AxesWalker(lpi, Axis.DESCENDANT);
      break;
    case OpCodes.FROM_DESCENDANTS_OR_SELF :
      prevIsOneStepDown = false;
      ai = new AxesWalker(lpi, Axis.DESCENDANTORSELF);
      break;
    case OpCodes.FROM_FOLLOWING :
      prevIsOneStepDown = false;
      ai = new AxesWalker(lpi, Axis.FOLLOWING);
      break;
    case OpCodes.FROM_FOLLOWING_SIBLINGS :
      prevIsOneStepDown = false;
      ai = new AxesWalker(lpi, Axis.FOLLOWINGSIBLING);
      break;
    case OpCodes.FROM_PRECEDING :
      prevIsOneStepDown = false;
      ai = new ReverseAxesWalker(lpi, Axis.PRECEDING);
      break;
    case OpCodes.FROM_PRECEDING_SIBLINGS :
      prevIsOneStepDown = false;
      ai = new ReverseAxesWalker(lpi, Axis.PRECEDINGSIBLING);
      break;
    case OpCodes.FROM_PARENT :
      prevIsOneStepDown = false;
      ai = new ReverseAxesWalker(lpi, Axis.PARENT);
      break;
    case OpCodes.FROM_SELF :
      ai = new AxesWalker(lpi, Axis.SELF);
      break;
    default :
      throw new RuntimeException(XSLMessages.createXPATHMessage(XPATHErrorResources.ER_NULL_ERROR_HANDLER, new Object[]{Integer.toString(stepType)})); //"Programmer's assertion: unknown opcode: "
                                 //+ stepType);
    }

    if (simpleInit)
    {
      ai.initNodeTest(DTMFilter.SHOW_ALL);
    }
    else
    {
      int whatToShow = compiler.getWhatToShow(opPos);

      /*
      System.out.print("construct: ");
      NodeTest.debugWhatToShow(whatToShow);
      System.out.println("or stuff: "+(whatToShow & (DTMFilter.SHOW_ATTRIBUTE
                             | DTMFilter.SHOW_ELEMENT
                             | DTMFilter.SHOW_PROCESSING_INSTRUCTION)));
      */
      if ((0 == (whatToShow
                 & (DTMFilter.SHOW_ATTRIBUTE | DTMFilter.SHOW_NAMESPACE | DTMFilter.SHOW_ELEMENT
                    | DTMFilter.SHOW_PROCESSING_INSTRUCTION))) || (whatToShow == DTMFilter.SHOW_ALL))
        ai.initNodeTest(whatToShow);
      else
      {
        ai.initNodeTest(whatToShow, compiler.getStepNS(opPos),
                        compiler.getStepLocalName(opPos));
      }
    }

    return ai;
  }
  
  public static String getAnalysisString(int analysis)
  {
    StringBuffer buf = new StringBuffer();
    buf.append("count: "+getStepCount(analysis)+" ");
    if((analysis & BIT_NODETEST_ANY) != 0)
    {
      buf.append("NTANY|");
    }
    if((analysis & BIT_PREDICATE) != 0)
    {
      buf.append("PRED|");
    }
    if((analysis & BIT_ANCESTOR) != 0)
    {
      buf.append("ANC|");
    }
    if((analysis & BIT_ANCESTOR_OR_SELF) != 0)
    {
      buf.append("ANCOS|");
    }
    if((analysis & BIT_ATTRIBUTE) != 0)
    {
      buf.append("ATTR|");
    }
    if((analysis & BIT_CHILD) != 0)
    {
      buf.append("CH|");
    }
    if((analysis & BIT_DESCENDANT) != 0)
    {
      buf.append("DESC|");
    }
    if((analysis & BIT_DESCENDANT_OR_SELF) != 0)
    {
      buf.append("DESCOS|");
    }
    if((analysis & BIT_FOLLOWING) != 0)
    {
      buf.append("FOL|");
    }
    if((analysis & BIT_FOLLOWING_SIBLING) != 0)
    {
      buf.append("FOLS|");
    }
    if((analysis & BIT_NAMESPACE) != 0)
    {
      buf.append("NS|");
    }
    if((analysis & BIT_PARENT) != 0)
    {
      buf.append("P|");
    }
    if((analysis & BIT_PRECEDING) != 0)
    {
      buf.append("PREC|");
    }
    if((analysis & BIT_PRECEDING_SIBLING) != 0)
    {
      buf.append("PRECS|");
    }
    if((analysis & BIT_SELF) != 0)
    {
      buf.append(".|");
    }
    if((analysis & BIT_FILTER) != 0)
    {
      buf.append("FLT|");
    }
    if((analysis & BIT_ROOT) != 0)
    {
      buf.append("R|");
    }
    return buf.toString();
  }

  /** Set to true for diagnostics about walker creation */
  static final boolean DEBUG_PATTERN_CREATION = false;

  /** Set to true for diagnostics about walker creation */
  static final boolean DEBUG_WALKER_CREATION = false;

  /** Set to true for diagnostics about iterator creation */
  static final boolean DEBUG_ITERATOR_CREATION = false;
  
  public static boolean hasPredicate(int analysis)
  {
    return (0 != (analysis & BIT_PREDICATE));
  }

  public static boolean isWild(int analysis)