001    /*
002     * Copyright (C) 2010 eXo Platform SAS.
003     *
004     * This is free software; you can redistribute it and/or modify it
005     * under the terms of the GNU Lesser General Public License as
006     * published by the Free Software Foundation; either version 2.1 of
007     * the License, or (at your option) any later version.
008     *
009     * This software is distributed in the hope that it will be useful,
010     * but WITHOUT ANY WARRANTY; without even the implied warranty of
011     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012     * Lesser General Public License for more details.
013     *
014     * You should have received a copy of the GNU Lesser General Public
015     * License along with this software; if not, write to the Free
016     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018     */
019    
020    package org.crsh.cmdline.spi;
021    
022    /**
023     * A typed string, this class should be extended to provide meta information about a string and provide type safety.
024     * This class is immutable and so should be its subclasses.
025     *
026     * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
027     * @version $Revision$
028     */
029    public abstract class Value {
030    
031      /** . */
032      private final String string;
033    
034      /**
035       * The only constructors that accepts a string.
036       *
037       * @param string the string value
038       * @throws NullPointerException if the string is null
039       */
040      public Value(String string) throws NullPointerException {
041        if (string == null) {
042          throw new NullPointerException("No null string accepted");
043        }
044        this.string = string;
045      }
046    
047      @Override
048      public int hashCode() {
049        return getClass().hashCode() ^ string.hashCode();
050      }
051    
052      @Override
053      public boolean equals(Object obj) {
054        if (obj == this) {
055          return true;
056        } else if (obj != null && obj.getClass().equals(getClass())) {
057          Value that = (Value)obj;
058          return string.equals(that.string);
059        }
060        return false;
061      }
062    
063      /**
064       * Returns the string value.
065       *
066       * @return the string value
067       */
068      public final String getString() {
069        return string;
070      }
071    
072      @Override
073      public final String toString() {
074        return string;
075      }
076    }