retoken.java

用java 编写的源码开放的文本编辑器。有很多有用的特性

/*
 *  gnu/regexp/REToken.java
 *  Copyright (C) 1998-2001 Wes Biggs
 *
 *  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.  See the
 *  GNU Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

package gnu.regexp;
import java.io.Serializable;

abstract class REToken implements Serializable {

  protected REToken next = null;
  protected REToken uncle = null;
  protected int subIndex;

  protected REToken(int subIndex) {
      this.subIndex = subIndex;
  }

  int getMinimumLength() {
    return 0;
  }

  void setUncle(REToken anUncle) {
    uncle = anUncle;
  }

    /** Returns true if the match succeeded, false if it failed. */
    abstract boolean match(CharIndexed input, REMatch mymatch);
  
    /** Returns true if the rest of the tokens match, false if they fail. */
    protected boolean next(CharIndexed input, REMatch mymatch) {
	if (next == null) {
	    if (uncle == null) {
		return true;
	    } else {
		return uncle.match(input, mymatch);
	    }
	} else {
	    return next.match(input, mymatch);
	}
    }
  
  boolean chain(REToken token) {
      next = token;
      return true; // Token was accepted
  }

    abstract void dump(StringBuffer os);

  void dumpAll(StringBuffer os) {
    dump(os);
    if (next != null) next.dumpAll(os);
  }
}