import com.sun.org.apache.xpath.internal.compiler.Compiler; //导入依赖的package包/类
/**
 * Create a LocPathIterator object, including creation
 * of step walkers from the opcode list, and call back
 * into the Compiler to create predicate expressions.
 *
 * @param compiler The Compiler which is creating
 * this expression.
 * @param opPos The position of this iterator in the
 * opcode list from the compiler.
 *
 * @throws javax.xml.transform.TransformerException
 */
protected BasicTestIterator(Compiler compiler, int opPos, int analysis)
        throws javax.xml.transform.TransformerException
{
  super(compiler, opPos, analysis, false);

  int firstStepPos = OpMap.getFirstChildPos(opPos);
  int whatToShow = compiler.getWhatToShow(firstStepPos);

  if ((0 == (whatToShow
             & (DTMFilter.SHOW_ATTRIBUTE
             | DTMFilter.SHOW_NAMESPACE
             | DTMFilter.SHOW_ELEMENT
             | DTMFilter.SHOW_PROCESSING_INSTRUCTION)))
             || (whatToShow == DTMFilter.SHOW_ALL))
    initNodeTest(whatToShow);
  else
  {
    initNodeTest(whatToShow, compiler.getStepNS(firstStepPos),
                            compiler.getStepLocalName(firstStepPos));
  }
  initPredicateInfo(compiler, firstStepPos);
}
 

import com.sun.org.apache.xpath.internal.compiler.Compiler; //导入依赖的package包/类
/**
 * Init predicate info.
 *
 * @param compiler The Compiler object that has information about this
 *                 walker in the op map.
 * @param opPos The op code position of this location step.
 *
 * @throws javax.xml.transform.TransformerException
 */
protected void initPredicateInfo(Compiler compiler, int opPos)
        throws javax.xml.transform.TransformerException
{

  int pos = compiler.getFirstPredicateOpPos(opPos);

  if(pos > 0)
  {
    m_predicates = compiler.getCompiledPredicates(pos);
    if(null != m_predicates)
    {
      for(int i = 0; i < m_predicates.length; i++)
      {
              m_predicates[i].exprSetParent(this);
      }
    }
  }
}
 

import com.sun.org.apache.xpath.internal.compiler.Compiler; //导入依赖的package包/类
/**
 * This method is for building an array of possible levels
 * where the target element(s) could be found for a match.
 * @param lpi The owning location path iterator.
 * @param compiler non-null reference to compiler object that has processed
 *                 the XPath operations into an opcode map.
 * @param stepOpCodePos The opcode position for the step.
 *
 * @return non-null AxesWalker derivative.
 *
 * @throws javax.xml.transform.TransformerException
 * @xsl.usage advanced
 */
static AxesWalker loadOneWalker(
        WalkingIterator lpi, Compiler compiler, int stepOpCodePos)
          throws javax.xml.transform.TransformerException
{

  AxesWalker firstWalker = null;
  int stepType = compiler.getOp(stepOpCodePos);

  if (stepType != OpCodes.ENDOP)
  {

    // m_axesWalkers = new AxesWalker[1];
    // As we unwind from the recursion, create the iterators.
    firstWalker = createDefaultWalker(compiler, stepType, lpi, 0);

    firstWalker.init(compiler, stepOpCodePos, stepType);
  }

  return firstWalker;
}
 

import com.sun.org.apache.xpath.internal.compiler.Compiler; //导入依赖的package包/类
/**
 * 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;
}
 

import com.sun.org.apache.xpath.internal.compiler.Compiler; //导入依赖的package包/类
/**
 * Create a OneStepIterator object.
 *
 * @param compiler A reference to the Compiler that contains the op map.
 * @param opPos The position within the op map, which contains the
 * location path expression for this itterator.
 *
 * @throws javax.xml.transform.TransformerException
 */
OneStepIterator(Compiler compiler, int opPos, int analysis)
        throws javax.xml.transform.TransformerException
{
  super(compiler, opPos, analysis);
  int firstStepPos = OpMap.getFirstChildPos(opPos);

  m_axis = WalkerFactory.getAxisFromStep(compiler, firstStepPos);

}
 

import com.sun.org.apache.xpath.internal.compiler.Compiler; //导入依赖的package包/类
/**
 * This method is for building an array of possible levels
 * where the target element(s) could be found for a match.
 * @param lpi The owning location path iterator object.
 * @param compiler non-null reference to compiler object that has processed
 *                 the XPath operations into an opcode map.
 * @param stepOpCodePos The opcode position for the step.
 * @param stepIndex The top-level step index withing the iterator.
 *
 * @return non-null AxesWalker derivative.
 *
 * @throws javax.xml.transform.TransformerException
 * @xsl.usage advanced
 */
static AxesWalker loadWalkers(
        WalkingIterator lpi, Compiler compiler, int stepOpCodePos, int stepIndex)
          throws javax.xml.transform.TransformerException
{

  int stepType;
  AxesWalker firstWalker = null;
  AxesWalker walker, prevWalker = null;

  int analysis = analyze(compiler, stepOpCodePos, stepIndex);

  while (OpCodes.ENDOP != (stepType = compiler.getOp(stepOpCodePos)))
  {
    walker = createDefaultWalker(compiler, stepOpCodePos, lpi, analysis);

    walker.init(compiler, stepOpCodePos, stepType);
    walker.exprSetParent(lpi);

    // walker.setAnalysis(analysis);
    if (null == firstWalker)
    {
      firstWalker = walker;
    }
    else
    {
      prevWalker.setNextWalker(walker);
      walker.setPrevWalker(prevWalker);
    }

    prevWalker = walker;
    stepOpCodePos = compiler.getNextStepPos(stepOpCodePos);

    if (stepOpCodePos < 0)
      break;
  }

  return firstWalker;
}
 

import com.sun.org.apache.xpath.internal.compiler.Compiler; //导入依赖的package包/类
static boolean functionProximateOrContainsProximate(Compiler compiler,
                                                    int opPos)
{
  int endFunc = opPos + compiler.getOp(opPos + 1) - 1;
  opPos = OpMap.getFirstChildPos(opPos);
  int funcID = compiler.getOp(opPos);
  //  System.out.println("funcID: "+funcID);
  //  System.out.println("opPos: "+opPos);
  //  System.out.println("endFunc: "+endFunc);
  switch(funcID)
  {
    case FunctionTable.FUNC_LAST:
    case FunctionTable.FUNC_POSITION:
      return true;
    default:
      opPos++;
      int i = 0;
      for (int p = opPos; p < endFunc; p = compiler.getNextOpPos(p), i++)
      {
        int innerExprOpPos = p+2;
        int argOp = compiler.getOp(innerExprOpPos);
        boolean prox = isProximateInnerExpr(compiler, innerExprOpPos);
        if(prox)
          return true;
      }

  }
  return false;
}
 

import com.sun.org.apache.xpath.internal.compiler.Compiler; //导入依赖的package包/类
static boolean isProximateInnerExpr(Compiler compiler, int opPos)
{
  int op = compiler.getOp(opPos);
  int innerExprOpPos = opPos+2;
  switch(op)
  {
    case OpCodes.OP_ARGUMENT:
      if(isProximateInnerExpr(compiler, innerExprOpPos))
        return true;
      break;
    case OpCodes.OP_VARIABLE:
    case OpCodes.OP_NUMBERLIT:
    case OpCodes.OP_LITERAL:
    case OpCodes.OP_LOCATIONPATH:
      break; // OK
    case OpCodes.OP_FUNCTION:
      boolean isProx = functionProximateOrContainsProximate(compiler, opPos);
      if(isProx)
        return true;
      break;
    case OpCodes.OP_GT:
    case OpCodes.OP_GTE:
    case OpCodes.OP_LT:
    case OpCodes.OP_LTE:
    case OpCodes.OP_EQUALS:
      int leftPos = OpMap.getFirstChildPos(op);
      int rightPos = compiler.getNextOpPos(leftPos);
      isProx = isProximateInnerExpr(compiler, leftPos);
      if(isProx)
        return true;
      isProx = isProximateInnerExpr(compiler, rightPos);
      if(isProx)
        return true;
      break;
    default:
      return true; // be conservative...
  }
  return false;
}
 

import com.sun.org.apache.xpath.internal.compiler.Compiler; //导入依赖的package包/类
/**
 * Create a OneStepIterator object.
 *
 * @param compiler A reference to the Compiler that contains the op map.
 * @param opPos The position within the op map, which contains the
 * location path expression for this itterator.
 *
 * @throws javax.xml.transform.TransformerException
 */
OneStepIteratorForward(Compiler compiler, int opPos, int analysis)
        throws javax.xml.transform.TransformerException
{
  super(compiler, opPos, analysis);
  int firstStepPos = OpMap.getFirstChildPos(opPos);

  m_axis = WalkerFactory.getAxisFromStep(compiler, firstStepPos);

}
 

import com.sun.org.apache.xpath.internal.compiler.Compiler; //导入依赖的package包/类
/**
 * Construct an XPath object.
 *
 * (Needs review -sc) This method initializes an XPathParser/
 * Compiler and compiles the expression.
 * @param exprString The XPath expression.
 * @param locator The location of the expression, may be null.
 * @param prefixResolver A prefix resolver to use to resolve prefixes to
 *                       namespace URIs.
 * @param type one of {@link #SELECT} or {@link #MATCH}.
 * @param errorListener The error listener, or null if default should be used.
 *
 * @throws javax.xml.transform.TransformerException if syntax or other error.
 */
public XPath(
        String exprString, SourceLocator locator, PrefixResolver prefixResolver, int type,
        ErrorListener errorListener)
          throws javax.xml.transform.TransformerException
{
  initFunctionTable();
  if(null == errorListener)
    errorListener = new com.sun.org.apache.xml.internal.utils.DefaultErrorHandler();

  m_patternString = exprString;

  XPathParser parser = new XPathParser(errorListener, locator);
  Compiler compiler = new Compiler(errorListener, locator, m_funcTable);

  if (SELECT == type)
    parser.initXPath(compiler, exprString, prefixResolver);
  else if (MATCH == type)
    parser.initMatchPattern(compiler, exprString, prefixResolver);
  else
    throw new RuntimeException(XSLMessages.createXPATHMessage(XPATHErrorResources.ER_CANNOT_DEAL_XPATH_TYPE, new Object[]{Integer.toString(type)})); //"Can not deal with XPath type: " + type);

  // System.out.println("----------------");
  Expression expr = compiler.compile(0);

  // System.out.println("expr: "+expr);
  this.setExpression(expr);

  if((null != locator) && locator instanceof ExpressionNode)
  {
      expr.exprSetParent((ExpressionNode)locator);
  }

}