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.matcher;
021    
022    import java.util.HashMap;
023    import java.util.Map;
024    
025    /**
026     * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
027     * @version $Revision$
028     */
029    public class InvocationContext {
030    
031      /** . */
032      private final Map<Class<?>, Object> attributes;
033    
034      public InvocationContext() {
035        this.attributes = new HashMap<Class<?>, Object>();
036      }
037    
038      public <T> void setAttribute(Class<T> key, T value) {
039        if (key == null) {
040          throw new NullPointerException();
041        }
042        if (value == null) {
043          attributes.remove(key);
044        } else {
045          attributes.put(key, value);
046        }
047      }
048    
049      public <T> T getAttribute(Class<T> key) {
050        Object value = attributes.get(key);
051        return value != null ? key.cast(value) : null;
052      }
053    }