com.hp.hpl.sparta.xpath.Step Maven / Gradle / Ivy

Go to download
/* Generated by Together */

package com.hp.hpl.sparta.xpath;

import java.io.*;

/**
 * One of the steps which, separated by slashes, make up an XPath
 * expression.

  Copyright (C) 2002 Hewlett-Packard Company.
 This file is part of Sparta, an XML Parser, DOM, and XPath library.
 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU
 Lesser General Public License as published by the Free Software
 Foundation; either version 2.1 of the License, or (at your option)
 any later version.  This library is distributed in the hope that it
 will be useful, but WITHOUT ANY WARRANTY; without even the implied
 warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
 PURPOSE. 
 @version  $Date: 2003/07/18 00:01:42 $  $Revision: 1.3 $
 @author Eamonn O'Brien-Strain
 */
public class Step {

  public static Step DOT = new Step(ThisNodeTest.INSTANCE, TrueExpr.INSTANCE);

  Step(NodeTest nodeTest, BooleanExpr predicate) {
    nodeTest_ = nodeTest;
    predicate_ = predicate;
    multiLevel_ = false;
  }

  /**
     @precondition current token is 1st token in the node_test production.
     @postcondition current tok is tok after last tok of step production */
  Step(XPath xpath, boolean multiLevel, SimpleStreamTokenizer toks) throws XPathException,
      IOException {
    multiLevel_ = multiLevel;

    switch (toks.ttype) {
      case '.':
        if (toks.nextToken() == '.')
          nodeTest_ = ParentNodeTest.INSTANCE;
        else {
          toks.pushBack();
          nodeTest_ = ThisNodeTest.INSTANCE;
        }
        break;
      case '*':
        nodeTest_ = AllElementTest.INSTANCE;
        break;
      case '@':
        if (toks.nextToken() != SimpleStreamTokenizer.TT_WORD)
          throw new XPathException(xpath, "after @ in node test", toks, "name");
        nodeTest_ = new AttrTest(toks.sval);
        break;
      case SimpleStreamTokenizer.TT_WORD:
        if (toks.sval.equals("text")) {
          if (toks.nextToken() != '(' || toks.nextToken() != ')')
            throw new XPathException(xpath, "after text", toks, "()");
          nodeTest_ = TextTest.INSTANCE;
        } else
          nodeTest_ = new ElementTest(toks.sval);
        break;
      default:
        throw new XPathException(xpath, "at begininning of step", toks, "'.' or '*' or name");
    }
    if (toks.nextToken() == '[') {
      toks.nextToken();
      //current token is first token in expr production
      predicate_ = ExprFactory.createExpr(xpath, toks);
      //current token is 1st token after expr production
      if (toks.ttype != ']')
        throw new XPathException(xpath, "after predicate expression", toks, "]");
      toks.nextToken();
    } else
      predicate_ = TrueExpr.INSTANCE;
    //current token is token after step production
  }

  public String toString() {
    return nodeTest_.toString() + predicate_.toString();
  }

  /** Is this step preceeded by a '//' ? */
  public boolean isMultiLevel() {
    return multiLevel_;
  }

  /** Does this step evaluate to a string values (attribute values
      or text() nodes)*/
  public boolean isStringValue() {
    return nodeTest_.isStringValue();
  }

  public NodeTest getNodeTest() {
    return nodeTest_;
  }

  public BooleanExpr getPredicate() {
    return predicate_;
  }

  /**
   * @link aggregationByValue
   * @directed
   */
  private final NodeTest nodeTest_;

  /**
   * @link aggregationByValue
   * @directed
   * @label predicate
   */
  private final BooleanExpr predicate_;

  private final boolean multiLevel_;
}

// $Log: Step.java,v $
// Revision 1.3  2003/07/18 00:01:42  eobrain
// Make compatiblie with J2ME.  For example do not use "new"
// java.util classes.
//
// Revision 1.2  2002/12/06 23:39:07  eobrain
// Make objects that are always the same follow the Flyweight Pattern.
//
// Revision 1.1.1.1  2002/08/19 05:04:04  eobrain
// import from HP Labs internal CVS
//
// Revision 1.6  2002/08/18 23:38:59  eob
// Add copyright and other formatting and commenting in preparation for
// release to SourceForge.
//
// Revision 1.5  2002/06/14 19:41:29  eob
// Add handling of "text()" in XPath expressions.
//
// Revision 1.4  2002/06/04 05:28:00  eob
// Simplify use of visitor pattern to make code easier to understand.
//
// Revision 1.3  2002/05/23 21:13:43  eob
// Better error reporting.
//
// Revision 1.2  2002/02/04 22:12:14  eob
// Add handling of nodetest for attribute.
//
// Revision 1.1  2002/02/01 02:04:23  eob
// initial