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JavaCC is a parser/scanner generator for java.
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/* Copyright (c) 2006, Sun Microsystems, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the Sun Microsystems, Inc. nor the names of its
 *       contributors may be used to endorse or promote products derived from
 *       this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.javacc.parser;

import java.util.Set;

/**
 * Describes expansions - entities that may occur on the
 * right hand sides of productions.  This is the base class of
 * a bunch of other more specific classes.
 */

public class Expansion {

  /**
   * The line and column number of the construct that corresponds
   * most closely to this node.
   */
  private int line;

  private int column;

  /**
   * A reimplementing of Object.hashCode() to be deterministic.  This uses
   * the line and column fields to generate an arbitrary number - we assume
   * that this method is called only after line and column are set to
   * their actual values.
   */
  public int hashCode() {
    return getLine() + getColumn();
  }

  /**
   * An internal name for this expansion.  This is used to generate parser
   * routines.
   */
  String internal_name = "";

  /**
   * The parser routines are generated in three phases.  The generation
   * of the second and third phase are on demand only, and the third phase
   * can be recursive.  This variable is used to keep track of the
   * expansions for which phase 3 generations have been already added to
   * a list so that the recursion can be terminated.
   */
  boolean phase3done = false;

  /**
   * The parent of this expansion node.  In case this is the top level
   * expansion of the production it is a reference to the production node
   * otherwise it is a reference to another Expansion node.  In case this
   * is the top level of a lookahead expansion,then the parent is null.
   */
  public Object parent;

  /**
   * The ordinal of this node with respect to its parent.
   */
  int ordinal;

  /**
   * To avoid right-recursive loops when calculating follow sets, we use
   * a generation number which indicates if this expansion was visited
   * by LookaheadWalk.genFollowSet in the same generation.  New generations
   * are obtained by incrementing the static counter below, and the current
   * generation is stored in the non-static variable below.
   */
  public static long nextGenerationIndex = 1;
  public long myGeneration = 0;

  /**
   * This flag is used for bookkeeping by the minimumSize method in class
   * ParseEngine.
   */
  public boolean inMinimumSize = false;

   public static void reInit()
   {
      nextGenerationIndex = 1;
   }

  private String getSimpleName() {
    String name = getClass().getName();
    return name.substring(name.lastIndexOf(".")+1); // strip the package name
  }

  public String toString() {
    return "[" + getLine() + "," + getColumn() + " " + System.identityHashCode(this) + " " + getSimpleName() + "]";
  }

  protected static final String eol = System.getProperty("line.separator", "\n");
  protected StringBuffer dumpPrefix(int indent) {
    StringBuffer sb = new StringBuffer(128);
    for (int i = 0; i < indent; i++)
      sb.append("  ");
    return sb;
  }

  public StringBuffer dump(int indent, Set alreadyDumped) {
    StringBuffer value = dumpPrefix(indent).append(System.identityHashCode(this)).append(" ").append(getSimpleName());
    return value;
  }

  /**
   * @param column the column to set
   */
  void setColumn(int column) {
    this.column = column;
  }

  /**
   * @return the column
   */
  int getColumn() {
    return column;
  }

  /**
   * @param line the line to set
   */
  void setLine(int line) {
    this.line = line;
  }

  /**
   * @return the line
   */
  int getLine() {
    return line;
  }
}