compiler.java

java1.6众多例子参考

/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed 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,v 1.2.4.1 2005/09/14 19:47:10 jeffsuttor Exp $
 */
package com.sun.org.apache.xpath.internal.compiler;

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

import com.sun.org.apache.xalan.internal.res.XSLMessages;
import com.sun.org.apache.xml.internal.dtm.Axis;
import com.sun.org.apache.xml.internal.dtm.DTMFilter;
import com.sun.org.apache.xml.internal.dtm.DTMIterator;
import com.sun.org.apache.xml.internal.utils.PrefixResolver;
import com.sun.org.apache.xml.internal.utils.QName;
import com.sun.org.apache.xml.internal.utils.SAXSourceLocator;
import com.sun.org.apache.xpath.internal.Expression;
import com.sun.org.apache.xpath.internal.axes.UnionPathIterator;
import com.sun.org.apache.xpath.internal.axes.WalkerFactory;
import com.sun.org.apache.xpath.internal.functions.FuncExtFunction;
import com.sun.org.apache.xpath.internal.functions.FuncExtFunctionAvailable;
import com.sun.org.apache.xpath.internal.functions.Function;
import com.sun.org.apache.xpath.internal.functions.WrongNumberArgsException;
import com.sun.org.apache.xpath.internal.objects.XNumber;
import com.sun.org.apache.xpath.internal.objects.XString;
import com.sun.org.apache.xpath.internal.operations.And;
import com.sun.org.apache.xpath.internal.operations.Div;
import com.sun.org.apache.xpath.internal.operations.Equals;
import com.sun.org.apache.xpath.internal.operations.Gt;
import com.sun.org.apache.xpath.internal.operations.Gte;
import com.sun.org.apache.xpath.internal.operations.Lt;
import com.sun.org.apache.xpath.internal.operations.Lte;
import com.sun.org.apache.xpath.internal.operations.Minus;
import com.sun.org.apache.xpath.internal.operations.Mod;
import com.sun.org.apache.xpath.internal.operations.Mult;
import com.sun.org.apache.xpath.internal.operations.Neg;
import com.sun.org.apache.xpath.internal.operations.NotEquals;
import com.sun.org.apache.xpath.internal.operations.Operation;
import com.sun.org.apache.xpath.internal.operations.Or;
import com.sun.org.apache.xpath.internal.operations.Plus;
import com.sun.org.apache.xpath.internal.operations.UnaryOperation;
import com.sun.org.apache.xpath.internal.operations.Variable;
import com.sun.org.apache.xpath.internal.patterns.FunctionPattern;
import com.sun.org.apache.xpath.internal.patterns.NodeTest;
import com.sun.org.apache.xpath.internal.patterns.StepPattern;
import com.sun.org.apache.xpath.internal.patterns.UnionPattern;
import com.sun.org.apache.xpath.internal.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.usage advanced
 */
public class Compiler extends OpMap
{

  /**
   * 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.
   */
  public Compiler()
  {
    m_errorHandler = null;
    m_locator = null;
  }

  /**
   * 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.
   *
   * @param operation non-null reference to parent operation.
   * @param opPos The op map position of the parent operation.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   *
   * @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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.
   * 
   * @param opPos The current position in the m_opMap array.
   *
   * @return reference to {@link com.sun.org.apache.xpath.internal.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.