http://xml.apache.org/xalan-j/: Serializer to write out XML, HTML etc. as a stream of characters from an input DOM or from input SAX events. (The Apache Software Foundation) 
/*
 * 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: Compiler.java 468655 2006-10-28 07:12:06Z minchau $
 */
package org.apache.xpath.compiler;

import javax.xml.transform.ErrorListener;
import javax.xml.transform.SourceLocator;
import javax.xml.transform.TransformerException;

import org.apache.xalan.res.XSLMessages;
import org.apache.xml.dtm.Axis;
import org.apache.xml.dtm.DTMFilter;
import org.apache.xml.dtm.DTMIterator;
import org.apache.xml.utils.PrefixResolver;
import org.apache.xml.utils.QName;
import org.apache.xml.utils.SAXSourceLocator;
import org.apache.xpath.Expression;
import org.apache.xpath.axes.UnionPathIterator;
import org.apache.xpath.axes.WalkerFactory;
import org.apache.xpath.functions.FuncExtFunction;
import org.apache.xpath.functions.FuncExtFunctionAvailable;
import org.apache.xpath.functions.Function;
import org.apache.xpath.functions.WrongNumberArgsException;
import org.apache.xpath.objects.XNumber;
import org.apache.xpath.objects.XString;
import org.apache.xpath.operations.And;
import org.apache.xpath.operations.Div;
import org.apache.xpath.operations.Equals;
import org.apache.xpath.operations.Gt;
import org.apache.xpath.operations.Gte;
import org.apache.xpath.operations.Lt;
import org.apache.xpath.operations.Lte;
import org.apache.xpath.operations.Minus;
import org.apache.xpath.operations.Mod;
import org.apache.xpath.operations.Mult;
import org.apache.xpath.operations.Neg;
import org.apache.xpath.operations.NotEquals;
import org.apache.xpath.operations.Operation;
import org.apache.xpath.operations.Or;
import org.apache.xpath.operations.Plus;
import org.apache.xpath.operations.UnaryOperation;
import org.apache.xpath.operations.Variable;
import org.apache.xpath.patterns.FunctionPattern;
import org.apache.xpath.patterns.NodeTest;
import org.apache.xpath.patterns.StepPattern;
import org.apache.xpath.patterns.UnionPattern;
import org.apache.xpath.res.XPATHErrorResources;


An instance of this class compiles an XPath string expression into 
a Expression object.  This class compiles the string into a sequence 
of operation codes (op map) and then builds from that into an Expression 
tree.

@xsl.usageadvanced
/**
 * An instance of this class compiles an XPath string expression into 
 * a Expression object.  This class compiles the string into a sequence 
 * of operation codes (op map) and then builds from that into an Expression 
 * tree.
 * @xsl.usage advanced
 */
public class Compiler extends OpMap
{

  
Construct a Compiler object with a specific ErrorListener and 
SourceLocator where the expression is located.

Params:
  • errorHandler – Error listener where messages will be sent, or null 
                    if messages should be sent to System err.
  • locator – The location object where the expression lives, which 
               may be null, but which, if not null, must be valid over 
               the long haul, in other words, it will not be cloned.
  • fTable –  The FunctionTable object where the xpath build-in 
               functions are stored.
/**
   * Construct a Compiler object with a specific ErrorListener and 
   * SourceLocator where the expression is located.
   *
   * @param errorHandler Error listener where messages will be sent, or null 
   *                     if messages should be sent to System err.
   * @param locator The location object where the expression lives, which 
   *                may be null, but which, if not null, must be valid over 
   *                the long haul, in other words, it will not be cloned.
   * @param fTable  The FunctionTable object where the xpath build-in 
   *                functions are stored.
   */
  public Compiler(ErrorListener errorHandler, SourceLocator locator, 
            FunctionTable fTable)
  {
    m_errorHandler = errorHandler;
    m_locator = locator;
    m_functionTable = fTable;
  }

  
Construct a Compiler instance that has a null error listener and a 
null source locator.

/**
   * Construct a Compiler instance that has a null error listener and a 
   * null source locator.
   */
  public Compiler()
  {
    m_errorHandler = null;
    m_locator = null;
  }

  
Execute the XPath object from a given opcode position.

Params:
  • opPos – The current position in the xpath.m_opMap array.
Throws:
Returns:The result of the XPath.
@xsl.usageadvanced
/**
   * Execute the XPath object from a given opcode position.
   * @param opPos The current position in the xpath.m_opMap array.
   * @return The result of the XPath.
   *
   * @throws TransformerException if there is a syntax or other error.
   * @xsl.usage advanced
   */
  public Expression compile(int opPos) throws TransformerException
  {

    int op = getOp(opPos);

    Expression expr = null;
    // System.out.println(getPatternString()+"op: "+op);
    switch (op)
    {
    case OpCodes.OP_XPATH :
      expr = compile(opPos + 2); break;
    case OpCodes.OP_OR :
      expr = or(opPos); break;
    case OpCodes.OP_AND :
      expr = and(opPos); break;
    case OpCodes.OP_NOTEQUALS :
      expr = notequals(opPos); break;
    case OpCodes.OP_EQUALS :
      expr = equals(opPos); break;
    case OpCodes.OP_LTE :
      expr = lte(opPos); break;
    case OpCodes.OP_LT :
      expr = lt(opPos); break;
    case OpCodes.OP_GTE :
      expr = gte(opPos); break;
    case OpCodes.OP_GT :
      expr = gt(opPos); break;
    case OpCodes.OP_PLUS :
      expr = plus(opPos); break;
    case OpCodes.OP_MINUS :
      expr = minus(opPos); break;
    case OpCodes.OP_MULT :
      expr = mult(opPos); break;
    case OpCodes.OP_DIV :
      expr = div(opPos); break;
    case OpCodes.OP_MOD :
      expr = mod(opPos); break;
//    case OpCodes.OP_QUO :
//      expr = quo(opPos); break;
    case OpCodes.OP_NEG :
      expr = neg(opPos); break;
    case OpCodes.OP_STRING :
      expr = string(opPos); break;
    case OpCodes.OP_BOOL :
      expr = bool(opPos); break;
    case OpCodes.OP_NUMBER :
      expr = number(opPos); break;
    case OpCodes.OP_UNION :
      expr = union(opPos); break;
    case OpCodes.OP_LITERAL :
      expr = literal(opPos); break;
    case OpCodes.OP_VARIABLE :
      expr = variable(opPos); break;
    case OpCodes.OP_GROUP :
      expr = group(opPos); break;
    case OpCodes.OP_NUMBERLIT :
      expr = numberlit(opPos); break;
    case OpCodes.OP_ARGUMENT :
      expr = arg(opPos); break;
    case OpCodes.OP_EXTFUNCTION :
      expr = compileExtension(opPos); break;
    case OpCodes.OP_FUNCTION :
      expr = compileFunction(opPos); break;
    case OpCodes.OP_LOCATIONPATH :
      expr = locationPath(opPos); break;
    case OpCodes.OP_PREDICATE :
      expr = null; break;  // should never hit this here.
    case OpCodes.OP_MATCHPATTERN :
      expr = matchPattern(opPos + 2); break;
    case OpCodes.OP_LOCATIONPATHPATTERN :
      expr = locationPathPattern(opPos); break;
    case OpCodes.OP_QUO:
      error(XPATHErrorResources.ER_UNKNOWN_OPCODE,
            new Object[]{ "quo" });  //"ERROR! Unknown op code: "+m_opMap[opPos]);
      break;
    default :
      error(XPATHErrorResources.ER_UNKNOWN_OPCODE,
            new Object[]{ Integer.toString(getOp(opPos)) });  //"ERROR! Unknown op code: "+m_opMap[opPos]);
    }
//    if(null != expr)
//      expr.setSourceLocator(m_locator);

    return expr;
  }

  
Bottle-neck compilation of an operation with left and right operands.

Params:
  • operation – non-null reference to parent operation.
  • opPos – The op map position of the parent operation.
Throws:
Returns:reference to Operation instance.
/**
   * Bottle-neck compilation of an operation with left and right operands.
   *
   * @param operation non-null reference to parent operation.
   * @param opPos The op map position of the parent operation.
   *
   * @return reference to {@link org.apache.xpath.operations.Operation} instance.
   *
   * @throws TransformerException if there is a syntax or other error.
   */
  private Expression compileOperation(Operation operation, int opPos)
          throws TransformerException
  {

    int leftPos = getFirstChildPos(opPos);
    int rightPos = getNextOpPos(leftPos);

    operation.setLeftRight(compile(leftPos), compile(rightPos));

    return operation;
  }

  
Bottle-neck compilation of a unary operation.

Params:
  • unary – The parent unary operation.
  • opPos – The position in the op map of the parent operation.
Throws:
Returns:The unary argument.
/**
   * Bottle-neck compilation of a unary operation.
   *
   * @param unary The parent unary operation.
   * @param opPos The position in the op map of the parent operation.
   *
   * @return The unary argument.
   *
   * @throws TransformerException if syntax or other error occurs.
   */
  private Expression compileUnary(UnaryOperation unary, int opPos)
          throws TransformerException
  {

    int rightPos = getFirstChildPos(opPos);

    unary.setRight(compile(rightPos));

    return unary;
  }

  
Compile an 'or' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Or instance.
/**
   * Compile an 'or' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Or} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression or(int opPos) throws TransformerException
  {
    return compileOperation(new Or(), opPos);
  }

  
Compile an 'and' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to And instance.
/**
   * Compile an 'and' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.And} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression and(int opPos) throws TransformerException
  {
    return compileOperation(new And(), opPos);
  }

  
Compile a '!=' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to NotEquals instance.
/**
   * Compile a '!=' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.NotEquals} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression notequals(int opPos) throws TransformerException
  {
    return compileOperation(new NotEquals(), opPos);
  }

  
Compile a '=' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Equals instance.
/**
   * Compile a '=' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Equals} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression equals(int opPos) throws TransformerException
  {
    return compileOperation(new Equals(), opPos);
  }

  
Compile a '<=' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Lte instance.
/**
   * Compile a '<=' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Lte} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression lte(int opPos) throws TransformerException
  {
    return compileOperation(new Lte(), opPos);
  }

  
Compile a '<' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Lt instance.
/**
   * Compile a '<' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Lt} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression lt(int opPos) throws TransformerException
  {
    return compileOperation(new Lt(), opPos);
  }

  
Compile a '>=' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Gte instance.
/**
   * Compile a '>=' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Gte} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression gte(int opPos) throws TransformerException
  {
    return compileOperation(new Gte(), opPos);
  }

  
Compile a '>' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Gt instance.
/**
   * Compile a '>' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Gt} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression gt(int opPos) throws TransformerException
  {
    return compileOperation(new Gt(), opPos);
  }

  
Compile a '+' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Plus instance.
/**
   * Compile a '+' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Plus} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression plus(int opPos) throws TransformerException
  {
    return compileOperation(new Plus(), opPos);
  }

  
Compile a '-' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Minus instance.
/**
   * Compile a '-' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Minus} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression minus(int opPos) throws TransformerException
  {
    return compileOperation(new Minus(), opPos);
  }

  
Compile a '*' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Mult instance.
/**
   * Compile a '*' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Mult} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression mult(int opPos) throws TransformerException
  {
    return compileOperation(new Mult(), opPos);
  }

  
Compile a 'div' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Div instance.
/**
   * Compile a 'div' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Div} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression div(int opPos) throws TransformerException
  {
    return compileOperation(new Div(), opPos);
  }

  
Compile a 'mod' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Mod instance.
/**
   * Compile a 'mod' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Mod} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression mod(int opPos) throws TransformerException
  {
    return compileOperation(new Mod(), opPos);
  }

  /*
   * Compile a 'quo' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Quo} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
//  protected Expression quo(int opPos) throws TransformerException
//  {
//    return compileOperation(new Quo(), opPos);
//  }

  
Compile a unary '-' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Neg instance.
/**
   * Compile a unary '-' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Neg} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression neg(int opPos) throws TransformerException
  {
    return compileUnary(new Neg(), opPos);
  }

  
Compile a 'string(...)' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to String instance.
/**
   * Compile a 'string(...)' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.String} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression string(int opPos) throws TransformerException
  {
    return compileUnary(new org.apache.xpath.operations.String(), opPos);
  }

  
Compile a 'boolean(...)' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Bool instance.
/**
   * Compile a 'boolean(...)' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Bool} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression bool(int opPos) throws TransformerException
  {
    return compileUnary(new org.apache.xpath.operations.Bool(), opPos);
  }

  
Compile a 'number(...)' operation.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Number instance.
/**
   * Compile a 'number(...)' operation.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Number} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression number(int opPos) throws TransformerException
  {
    return compileUnary(new org.apache.xpath.operations.Number(), opPos);
  }

  
Compile a literal string value.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to XString instance.
/**
   * Compile a literal string value.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.objects.XString} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression literal(int opPos)
  {

    opPos = getFirstChildPos(opPos);

    return (XString) getTokenQueue().elementAt(getOp(opPos));
  }

  
Compile a literal number value.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to XNumber instance.
/**
   * Compile a literal number value.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.objects.XNumber} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression numberlit(int opPos)
  {

    opPos = getFirstChildPos(opPos);

    return (XNumber) getTokenQueue().elementAt(getOp(opPos));
  }

  
Compile a variable reference.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Variable instance.
/**
   * Compile a variable reference.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.operations.Variable} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression variable(int opPos) throws TransformerException
  {

    Variable var = new Variable();

    opPos = getFirstChildPos(opPos);

    int nsPos = getOp(opPos);
    java.lang.String namespace 
      = (OpCodes.EMPTY == nsPos) ? null 
                                   : (java.lang.String) getTokenQueue().elementAt(nsPos);
    java.lang.String localname 
      = (java.lang.String) getTokenQueue().elementAt(getOp(opPos+1));
    QName qname = new QName(namespace, localname);

    var.setQName(qname);

    return var;
  }

  
Compile an expression group.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to the contained expression.
/**
   * Compile an expression group.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to the contained expression.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression group(int opPos) throws TransformerException
  {

    // no-op
    return compile(opPos + 2);
  }

  
Compile a function argument.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to the argument expression.
/**
   * Compile a function argument.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to the argument expression.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression arg(int opPos) throws TransformerException
  {

    // no-op
    return compile(opPos + 2);
  }

  
Compile a location path union. The UnionPathIterator itself may create LocPathIterator children. 
Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to LocPathIterator instance.
/**
   * Compile a location path union. The UnionPathIterator itself may create
   * {@link org.apache.xpath.axes.LocPathIterator} children.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.axes.LocPathIterator} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression union(int opPos) throws TransformerException
  {
    locPathDepth++;
    try
    {
      return UnionPathIterator.createUnionIterator(this, opPos);
    }
    finally
    {
      locPathDepth--;
    }
  }
  
  private int locPathDepth = -1;
  
  
Get the level of the location path or union being constructed.  

Returns:0 if it is a top-level path.
/**
   * Get the level of the location path or union being constructed.  
   * @return 0 if it is a top-level path.
   */
  public int getLocationPathDepth()
  {
    return locPathDepth;
  }

  
Get the function table  

/**
   * Get the function table  
   */
  FunctionTable getFunctionTable()
  {
    return m_functionTable;
  }

  
Compile a location path. The LocPathIterator itself may create AxesWalker children. 
Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to LocPathIterator instance.
/**
   * Compile a location path.  The LocPathIterator itself may create
   * {@link org.apache.xpath.axes.AxesWalker} children.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.axes.LocPathIterator} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  public Expression locationPath(int opPos) throws TransformerException
  {
    locPathDepth++;
    try
    {
      DTMIterator iter = WalkerFactory.newDTMIterator(this, opPos, (locPathDepth == 0));
      return (Expression)iter; // cast OK, I guess.
    }
    finally
    {
      locPathDepth--;
    }
  }

  
Compile a location step predicate expression.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:the contained predicate expression.
/**
   * Compile a location step predicate expression.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return the contained predicate expression.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  public Expression predicate(int opPos) throws TransformerException
  {
    return compile(opPos + 2);
  }

  
Compile an entire match pattern expression.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to UnionPattern instance.
/**
   * Compile an entire match pattern expression.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.patterns.UnionPattern} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected Expression matchPattern(int opPos) throws TransformerException
  {
    locPathDepth++;
    try
    {
      // First, count...
      int nextOpPos = opPos;
      int i;

      for (i = 0; getOp(nextOpPos) == OpCodes.OP_LOCATIONPATHPATTERN; i++)
      {
        nextOpPos = getNextOpPos(nextOpPos);
      }

      if (i == 1)
        return compile(opPos);

      UnionPattern up = new UnionPattern();
      StepPattern[] patterns = new StepPattern[i];

      for (i = 0; getOp(opPos) == OpCodes.OP_LOCATIONPATHPATTERN; i++)
      {
        nextOpPos = getNextOpPos(opPos);
        patterns[i] = (StepPattern) compile(opPos);
        opPos = nextOpPos;
      }

      up.setPatterns(patterns);

      return up;
    }
    finally
    {
      locPathDepth--;
    }
  }

  
Compile a location match pattern unit expression.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to StepPattern instance.
/**
   * Compile a location match pattern unit expression.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.patterns.StepPattern} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  public Expression locationPathPattern(int opPos)
          throws TransformerException
  {

    opPos = getFirstChildPos(opPos);

    return stepPattern(opPos, 0, null);
  }

  
Get a NodeFilter bit set that tells what to show for a given node test. 
Params:
  • opPos – the op map position for the location step.
Returns:NodeFilter bit set that tells what to show for a given node test.
/**
   * Get a {@link org.w3c.dom.traversal.NodeFilter} bit set that tells what 
   * to show for a given node test.
   *
   * @param opPos the op map position for the location step.
   *
   * @return {@link org.w3c.dom.traversal.NodeFilter} bit set that tells what 
   *         to show for a given node test.
   */
  public int getWhatToShow(int opPos)
  {

    int axesType = getOp(opPos);
    int testType = getOp(opPos + 3);

    // System.out.println("testType: "+testType);
    switch (testType)
    {
    case OpCodes.NODETYPE_COMMENT :
      return DTMFilter.SHOW_COMMENT;
    case OpCodes.NODETYPE_TEXT :
//      return DTMFilter.SHOW_TEXT | DTMFilter.SHOW_COMMENT;
      return DTMFilter.SHOW_TEXT | DTMFilter.SHOW_CDATA_SECTION ;
    case OpCodes.NODETYPE_PI :
      return DTMFilter.SHOW_PROCESSING_INSTRUCTION;
    case OpCodes.NODETYPE_NODE :
//      return DTMFilter.SHOW_ALL;
      switch (axesType)
      {
      case OpCodes.FROM_NAMESPACE:
        return DTMFilter.SHOW_NAMESPACE;
      case OpCodes.FROM_ATTRIBUTES :
      case OpCodes.MATCH_ATTRIBUTE :
        return DTMFilter.SHOW_ATTRIBUTE;
      case OpCodes.FROM_SELF:
      case OpCodes.FROM_ANCESTORS_OR_SELF:
      case OpCodes.FROM_DESCENDANTS_OR_SELF:
        return DTMFilter.SHOW_ALL;
      default:
        if (getOp(0) == OpCodes.OP_MATCHPATTERN)
          return ~DTMFilter.SHOW_ATTRIBUTE
                  & ~DTMFilter.SHOW_DOCUMENT
                  & ~DTMFilter.SHOW_DOCUMENT_FRAGMENT;
        else
          return ~DTMFilter.SHOW_ATTRIBUTE;
      }
    case OpCodes.NODETYPE_ROOT :
      return DTMFilter.SHOW_DOCUMENT | DTMFilter.SHOW_DOCUMENT_FRAGMENT;
    case OpCodes.NODETYPE_FUNCTEST :
      return NodeTest.SHOW_BYFUNCTION;
    case OpCodes.NODENAME :
      switch (axesType)
      {
      case OpCodes.FROM_NAMESPACE :
        return DTMFilter.SHOW_NAMESPACE;
      case OpCodes.FROM_ATTRIBUTES :
      case OpCodes.MATCH_ATTRIBUTE :
        return DTMFilter.SHOW_ATTRIBUTE;

      // break;
      case OpCodes.MATCH_ANY_ANCESTOR :
      case OpCodes.MATCH_IMMEDIATE_ANCESTOR :
        return DTMFilter.SHOW_ELEMENT;

      // break;
      default :
        return DTMFilter.SHOW_ELEMENT;
      }
    default :
      // System.err.println("We should never reach here.");
      return DTMFilter.SHOW_ALL;
    }
  }
  
private static final boolean DEBUG = false;

  
Compile a step pattern unit expression, used for both location paths 
and match patterns.

Params:
  • opPos – The current position in the m_opMap array.
  • stepCount – The number of steps to expect.
  • ancestorPattern – The owning StepPattern, which may be null.
Throws:
Returns:reference to StepPattern instance.
/**
   * Compile a step pattern unit expression, used for both location paths 
   * and match patterns.
   * 
   * @param opPos The current position in the m_opMap array.
   * @param stepCount The number of steps to expect.
   * @param ancestorPattern The owning StepPattern, which may be null.
   *
   * @return reference to {@link org.apache.xpath.patterns.StepPattern} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  protected StepPattern stepPattern(
          int opPos, int stepCount, StepPattern ancestorPattern)
            throws TransformerException
  {

    int startOpPos = opPos;
    int stepType = getOp(opPos);

    if (OpCodes.ENDOP == stepType)
    {
      return null;
    }
    
    boolean addMagicSelf = true;

    int endStep = getNextOpPos(opPos);

    // int nextStepType = getOpMap()[endStep];
    StepPattern pattern;
    
    // boolean isSimple = ((OpCodes.ENDOP == nextStepType) && (stepCount == 0));
    int argLen;

    switch (stepType)
    {
    case OpCodes.OP_FUNCTION :
      if(DEBUG)
        System.out.println("MATCH_FUNCTION: "+m_currentPattern); 
      addMagicSelf = false;
      argLen = getOp(opPos + OpMap.MAPINDEX_LENGTH);
      pattern = new FunctionPattern(compileFunction(opPos), Axis.PARENT, Axis.CHILD);
      break;
    case OpCodes.FROM_ROOT :
      if(DEBUG)
        System.out.println("FROM_ROOT, "+m_currentPattern);
      addMagicSelf = false;
      argLen = getArgLengthOfStep(opPos);
      opPos = getFirstChildPosOfStep(opPos);
      pattern = new StepPattern(DTMFilter.SHOW_DOCUMENT | 
                                DTMFilter.SHOW_DOCUMENT_FRAGMENT,
                                Axis.PARENT, Axis.CHILD);
      break;
    case OpCodes.MATCH_ATTRIBUTE :
     if(DEBUG)
        System.out.println("MATCH_ATTRIBUTE: "+getStepLocalName(startOpPos)+", "+m_currentPattern);
      argLen = getArgLengthOfStep(opPos);
      opPos = getFirstChildPosOfStep(opPos);
      pattern = new StepPattern(DTMFilter.SHOW_ATTRIBUTE,
                                getStepNS(startOpPos),
                                getStepLocalName(startOpPos),
                                Axis.PARENT, Axis.ATTRIBUTE);
      break;
    case OpCodes.MATCH_ANY_ANCESTOR :
      if(DEBUG)
        System.out.println("MATCH_ANY_ANCESTOR: "+getStepLocalName(startOpPos)+", "+m_currentPattern);
      argLen = getArgLengthOfStep(opPos);
      opPos = getFirstChildPosOfStep(opPos);
      int what = getWhatToShow(startOpPos);
      // bit-o-hackery, but this code is due for the morgue anyway...
      if(0x00000500 == what)
        addMagicSelf = false;
      pattern = new StepPattern(getWhatToShow(startOpPos),
                                        getStepNS(startOpPos),
                                        getStepLocalName(startOpPos),
                                        Axis.ANCESTOR, Axis.CHILD);
      break;
    case OpCodes.MATCH_IMMEDIATE_ANCESTOR :
      if(DEBUG)
        System.out.println("MATCH_IMMEDIATE_ANCESTOR: "+getStepLocalName(startOpPos)+", "+m_currentPattern);
      argLen = getArgLengthOfStep(opPos);
      opPos = getFirstChildPosOfStep(opPos);
      pattern = new StepPattern(getWhatToShow(startOpPos),
                                getStepNS(startOpPos),
                                getStepLocalName(startOpPos),
                                Axis.PARENT, Axis.CHILD);
      break;
    default :
      error(XPATHErrorResources.ER_UNKNOWN_MATCH_OPERATION, null);  //"unknown match operation!");

      return null;
    }

    pattern.setPredicates(getCompiledPredicates(opPos + argLen));
    if(null == ancestorPattern)
    {
      // This is the magic and invisible "." at the head of every 
      // match pattern, and corresponds to the current node in the context 
      // list, from where predicates are counted.
      // So, in order to calculate "foo[3]", it has to count from the 
      // current node in the context list, so, from that current node, 
      // the full pattern is really "self::node()/child::foo[3]".  If you 
      // translate this to a select pattern from the node being tested, 
      // which is really how we're treating match patterns, it works out to 
      // self::foo/parent::node[child::foo[3]]", or close enough.
	/*      if(addMagicSelf && pattern.getPredicateCount() > 0)
      {
        StepPattern selfPattern = new StepPattern(DTMFilter.SHOW_ALL, 
                                                  Axis.PARENT, Axis.CHILD);
        // We need to keep the new nodetest from affecting the score...
        XNumber score = pattern.getStaticScore();
        pattern.setRelativePathPattern(selfPattern);
        pattern.setStaticScore(score);
        selfPattern.setStaticScore(score);
	}*/
    }
    else
    {
      // System.out.println("Setting "+ancestorPattern+" as relative to "+pattern);
      pattern.setRelativePathPattern(ancestorPattern);
    }

    StepPattern relativePathPattern = stepPattern(endStep, stepCount + 1,
                                        pattern);

    return (null != relativePathPattern) ? relativePathPattern : pattern;
  }

  
Compile a zero or more predicates for a given match pattern.

Params:
  • opPos – The position of the first predicate the m_opMap array.
Throws:
Returns:reference to array of Expression instances.
/**
   * Compile a zero or more predicates for a given match pattern.
   * 
   * @param opPos The position of the first predicate the m_opMap array.
   *
   * @return reference to array of {@link org.apache.xpath.Expression} instances.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  public Expression[] getCompiledPredicates(int opPos)
          throws TransformerException
  {

    int count = countPredicates(opPos);

    if (count > 0)
    {
      Expression[] predicates = new Expression[count];

      compilePredicates(opPos, predicates);

      return predicates;
    }

    return null;
  }

  
Count the number of predicates in the step.

Params:
  • opPos – The position of the first predicate the m_opMap array.
Throws:
Returns:The number of predicates for this step.
/**
   * Count the number of predicates in the step.
   *
   * @param opPos The position of the first predicate the m_opMap array.
   *
   * @return The number of predicates for this step.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  public int countPredicates(int opPos) throws TransformerException
  {

    int count = 0;

    while (OpCodes.OP_PREDICATE == getOp(opPos))
    {
      count++;

      opPos = getNextOpPos(opPos);
    }

    return count;
  }

  
Compiles predicates in the step.

Params:
  • opPos – The position of the first predicate the m_opMap array.
  • predicates – An empty pre-determined array of Expressions, that will be filled in.
Throws:
/**
   * Compiles predicates in the step.
   *
   * @param opPos The position of the first predicate the m_opMap array.
   * @param predicates An empty pre-determined array of 
   *            {@link org.apache.xpath.Expression}s, that will be filled in.
   *
   * @throws TransformerException
   */
  private void compilePredicates(int opPos, Expression[] predicates)
          throws TransformerException
  {

    for (int i = 0; OpCodes.OP_PREDICATE == getOp(opPos); i++)
    {
      predicates[i] = predicate(opPos);
      opPos = getNextOpPos(opPos);
    }
  }

  
Compile a built-in XPath function.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to Function instance.
/**
   * Compile a built-in XPath function.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.functions.Function} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  Expression compileFunction(int opPos) throws TransformerException
  {

    int endFunc = opPos + getOp(opPos + 1) - 1;

    opPos = getFirstChildPos(opPos);

    int funcID = getOp(opPos);

    opPos++;

    if (-1 != funcID)
    {
      Function func = m_functionTable.getFunction(funcID);
      
      /**
       * It is a trick for function-available. Since the function table is an
       * instance field, insert this table at compilation time for later usage
       */
      
      if (func instanceof FuncExtFunctionAvailable)
          ((FuncExtFunctionAvailable) func).setFunctionTable(m_functionTable);

      func.postCompileStep(this);
      
      try
      {
        int i = 0;

        for (int p = opPos; p < endFunc; p = getNextOpPos(p), i++)
        {

          // System.out.println("argPos: "+ p);
          // System.out.println("argCode: "+ m_opMap[p]);
          func.setArg(compile(p), i);
        }

        func.checkNumberArgs(i);
      }
      catch (WrongNumberArgsException wnae)
      {
        java.lang.String name = m_functionTable.getFunctionName(funcID);

        m_errorHandler.fatalError( new TransformerException(
                  XSLMessages.createXPATHMessage(XPATHErrorResources.ER_ONLY_ALLOWS, 
                      new Object[]{name, wnae.getMessage()}), m_locator)); 
              //"name + " only allows " + wnae.getMessage() + " arguments", m_locator));
      }

      return func;
    }
    else
    {
      error(XPATHErrorResources.ER_FUNCTION_TOKEN_NOT_FOUND, null);  //"function token not found.");

      return null;
    }
  }

  // The current id for extension functions.
  private static long s_nextMethodId = 0;

  
Get the next available method id

/**
   * Get the next available method id
   */
  synchronized private long getNextMethodId()
  {
    if (s_nextMethodId == Long.MAX_VALUE)
      s_nextMethodId = 0;
    
    return s_nextMethodId++;
  }
  
  
Compile an extension function.

Params:
  • opPos – The current position in the m_opMap array.
Throws:
Returns:reference to FuncExtFunction instance.
/**
   * Compile an extension function.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link org.apache.xpath.functions.FuncExtFunction} instance.
   *
   * @throws TransformerException if a error occurs creating the Expression.
   */
  private Expression compileExtension(int opPos)
          throws TransformerException
  {

    int endExtFunc = opPos + getOp(opPos + 1) - 1;

    opPos = getFirstChildPos(opPos);

    java.lang.String ns = (java.lang.String) getTokenQueue().elementAt(getOp(opPos));

    opPos++;

    java.lang.String funcName =
      (java.lang.String) getTokenQueue().elementAt(getOp(opPos));

    opPos++;

    // We create a method key to uniquely identify this function so that we
    // can cache the object needed to invoke it.  This way, we only pay the
    // reflection overhead on the first call.

    Function extension = new FuncExtFunction(ns, funcName, String.valueOf(getNextMethodId()));

    try
    {
      int i = 0;

      while (opPos < endExtFunc)
      {
        int nextOpPos = getNextOpPos(opPos);

        extension.setArg(this.compile(opPos), i);

        opPos = nextOpPos;

        i++;
      }
    }
    catch (WrongNumberArgsException wnae)
    {
      ;  // should never happen
    }

    return extension;
  }

  
Warn the user of an problem.

Params:
  • msg – An error msgkey that corresponds to one of the constants found in XPATHErrorResources, which is a key for a format string.
  • args – An array of arguments represented in the format string, which 
            may be null.
Throws:
/**
   * Warn the user of an problem.
   *
   * @param msg An error msgkey that corresponds to one of the constants found 
   *            in {@link org.apache.xpath.res.XPATHErrorResources}, which is 
   *            a key for a format string.
   * @param args An array of arguments represented in the format string, which 
   *             may be null.
   *
   * @throws TransformerException if the current ErrorListoner determines to 
   *                              throw an exception.
   */
  public void warn(String msg, Object[] args) throws TransformerException
  {

    java.lang.String fmsg = XSLMessages.createXPATHWarning(msg, args);

    if (null != m_errorHandler)
    {
      m_errorHandler.warning(new TransformerException(fmsg, m_locator));
    }
    else
    {
      System.out.println(fmsg
                          +"; file "+m_locator.getSystemId()
                          +"; line "+m_locator.getLineNumber()
                          +"; column "+m_locator.getColumnNumber());
    }
  }

  
Tell the user of an assertion error, and probably throw an
exception.

Params:
  • b –  If false, a runtime exception will be thrown.
  • msg – The assertion message, which should be informative.
Throws:
/**
   * Tell the user of an assertion error, and probably throw an
   * exception.
   *
   * @param b  If false, a runtime exception will be thrown.
   * @param msg The assertion message, which should be informative.
   * 
   * @throws RuntimeException if the b argument is false.
   */
  public void assertion(boolean b, java.lang.String msg)
  {

    if (!b)
    {
      java.lang.String fMsg = XSLMessages.createXPATHMessage(
        XPATHErrorResources.ER_INCORRECT_PROGRAMMER_ASSERTION,
        new Object[]{ msg });

      throw new RuntimeException(fMsg);
    }
  }

  
Tell the user of an error, and probably throw an
exception.

Params:
  • msg – An error msgkey that corresponds to one of the constants found in XPATHErrorResources, which is a key for a format string.
  • args – An array of arguments represented in the format string, which 
            may be null.
Throws:
/**
   * Tell the user of an error, and probably throw an
   * exception.
   *
   * @param msg An error msgkey that corresponds to one of the constants found 
   *            in {@link org.apache.xpath.res.XPATHErrorResources}, which is 
   *            a key for a format string.
   * @param args An array of arguments represented in the format string, which 
   *             may be null.
   *
   * @throws TransformerException if the current ErrorListoner determines to 
   *                              throw an exception.
   */
  public void error(String msg, Object[] args) throws TransformerException
  {

    java.lang.String fmsg = XSLMessages.createXPATHMessage(msg, args);
    

    if (null != m_errorHandler)
    {
      m_errorHandler.fatalError(new TransformerException(fmsg, m_locator));
    }
    else
    {

      // System.out.println(te.getMessage()
      //                    +"; file "+te.getSystemId()
      //                    +"; line "+te.getLineNumber()
      //                    +"; column "+te.getColumnNumber());
      throw new TransformerException(fmsg, (SAXSourceLocator)m_locator);
    }
  }

  
The current prefixResolver for the execution context.

/**
   * The current prefixResolver for the execution context.
   */
  private PrefixResolver m_currentPrefixResolver = null;

  
Get the current namespace context for the xpath.

Returns:The current prefix resolver, *may* be null, though hopefully not.
/**
   * Get the current namespace context for the xpath.
   *
   * @return The current prefix resolver, *may* be null, though hopefully not.
   */
  public PrefixResolver getNamespaceContext()
  {
    return m_currentPrefixResolver;
  }

  
Set the current namespace context for the xpath.

Params:
  • pr – The resolver for prefixes in the XPath expression.
/**
   * Set the current namespace context for the xpath.
   *
   * @param pr The resolver for prefixes in the XPath expression.
   */
  public void setNamespaceContext(PrefixResolver pr)
  {
    m_currentPrefixResolver = pr;
  }

  
The error listener where errors will be sent.  If this is null, errors 
 and warnings will be sent to System.err.  May be null.    
/** The error listener where errors will be sent.  If this is null, errors 
   *  and warnings will be sent to System.err.  May be null.    */
  ErrorListener m_errorHandler;

  
The source locator for the expression being compiled.  May be null. 
/** The source locator for the expression being compiled.  May be null. */
  SourceLocator m_locator;
  
  
The FunctionTable for all xpath build-in functions

/**
   * The FunctionTable for all xpath build-in functions
   */
  private FunctionTable m_functionTable;
}