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.command;
021    
022    import org.crsh.cmdline.CommandCompletion;
023    
024    /**
025     * <p>The shell command allows a single source to provide a customized invoker according to the context
026     * of the arguments. More importantly it allows to decouple the obtention of a command related to its
027     * arguments from the actual execution of the command. This somewhat matters because the command execution
028     * pipeline has notion of consumed and produced types, thanks to this, the consumed and produced
029     * types can vary according to the arguments.</p>
030     *
031     * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
032     * @version $Revision$
033     */
034    public interface ShellCommand {
035    
036      /**
037       * Provide completions for the specified arguments.
038       *
039       * @param context the command context
040       * @param line the original command line arguments
041       * @return the completions
042       */
043      CommandCompletion complete(CommandContext context, String line);
044    
045      /**
046       * Returns a description of the command or null if none can be found.
047       *
048       * @param line the usage line
049       * @param mode the description mode
050       * @return the description
051       */
052      String describe(String line, DescriptionFormat mode);
053    
054      /**
055       * Provides an invoker for the specified arguments.
056       *
057       * @param line the command line arguments
058       * @return the command to provide
059       */
060      CommandInvoker<?, ?> createInvoker(String line);
061    
062    }