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 */
019package org.crsh.command;
020
021import org.crsh.io.Filter;
022
023import 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 */
031public 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}