eofactions.java

java语法解释器生成器

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * JFlex 1.4.2                                                             *
 * Copyright (C) 1998-2008  Gerwin Klein <[e-mail]>                    *
 * All rights reserved.                                                    *
 *                                                                         *
 * This program is free software; you can redistribute it and/or modify    *
 * it under the terms of the GNU General Public License. See the file      *
 * COPYRIGHT for more information.                                         *
 *                                                                         *
 * This program 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.  See the           *
 * GNU General Public License for more details.                            *
 *                                                                         *
 * You should have received a copy of the GNU General Public License along *
 * with this program; if not, write to the Free Software Foundation, Inc., *
 * 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA                 *
 *                                                                         *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

package JFlex;

import java.util.*;


/**
 * A simple table to store EOF actions for each lexical state.
 *
 * @author Gerwin Klein
 * @version JFlex 1.4.2, $Revision: 358 $, $Date: 2008-05-27 16:28:29 +1000 (Tue, 27 May 2008) $
 */
public class EOFActions {

  /** maps lexical states to actions */
  private Hashtable /* Integer -> Action */ actions = new Hashtable();
  private Action defaultAction;
  private int numLexStates;

  public void setNumLexStates(int num) {
    numLexStates = num;
  }

  public void add(Vector stateList, Action action) {

    if (stateList != null && stateList.size() > 0) {
      Enumeration states = stateList.elements();
      
      while (states.hasMoreElements()) 
        add( (Integer) states.nextElement(), action );   
    }
    else {
      defaultAction = action.getHigherPriority(defaultAction);
      
      for (int i = 0; i < numLexStates; i++) {
        Integer state = new Integer(i);
        if ( actions.get(state) != null ) {
          Action oldAction = (Action) actions.get(state);
          actions.put(state, oldAction.getHigherPriority(action));
        }
      }
    }
  }

  public void add(Integer state, Action action) {
    if ( actions.get(state) == null )
      actions.put(state, action);
    else {
      Action oldAction = (Action) actions.get(state);
      actions.put(state, oldAction.getHigherPriority(action));
    }
  }

  public boolean isEOFAction(Object a) {
    if (a == defaultAction) return true;

    Enumeration e = actions.elements();
    while ( e.hasMoreElements() ) 
      if (a == e.nextElement()) return true;

    return false;
  }

  public Action getAction(int state) {
    return (Action) actions.get(new Integer(state));
  }

  public Action getDefault() {
    return defaultAction;
  }

  public int numActions() {
    return actions.size();
  }
}