001    /*
002     * Copyright (C) 2012 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    package org.crsh.command;
020    
021    import org.crsh.io.Filter;
022    
023    import java.io.IOException;
024    
025    /**
026     * A command invoker is a filter for a {@link CommandContext} kind of consumer.
027     *
028     * @param <C> the consumed element generic type
029     * @param <P> the produced element generic type
030     */
031    public abstract class CommandInvoker<C, P> implements Filter<C, P, CommandContext<? super P>> {
032    
033      /**
034       * Invoke the command.
035       *
036       * @param consumer the consumer for this invocation
037       * @throws IOException any io exception
038       */
039      public final void invoke(CommandContext<? super P> consumer) throws IOException {
040        try {
041          open(consumer);
042        }
043        finally {
044          try {
045            flush();
046          }
047          finally {
048            close();
049          }
050        }
051      }
052    
053    }