001    /*
002     * Copyright (C) 2003-2009 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 java.io.PrintWriter;
023    
024    /**
025     * The invocation context provided to a command during the invocation phase. The invocation context provides the
026     * various interactions that a command can perform with its context during its invocation.
027     *
028     * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
029     * @version $Revision$
030     */
031    public interface InvocationContext<C, P> extends CommandContext {
032    
033      /**
034       * Returns the term width in chars. When the value is not positive it means the value could not be determined.
035       *
036       * @return the term width
037       */
038      int getWidth();
039    
040      /**
041       * Returns a generic property.
042       *
043       * @param propertyName the property name
044       * @return the property value
045       */
046      String getProperty(String propertyName);
047    
048      /**
049       * Display a message and read a line on the console.
050       *
051       * @param msg the message to display before reading a line
052       * @param echo wether or not the line read should be echoed when typing
053       * @return the line read
054       */
055      String readLine(String msg, boolean echo);
056    
057      /**
058       * Returns the writer for the output.
059       *
060       * @return the writer
061       */
062      PrintWriter getWriter();
063    
064      /**
065       * Returns true if the command is involved in a pipe operation and receives a stream.
066       *
067       * @return true if the command is involved in a pipe
068       */
069      boolean isPiped();
070    
071      /**
072       * Returns an iterator over the stream of consumed items.
073       *
074       * @return the consumed items
075       * @throws IllegalStateException if the command is not involved in a pipe operation
076       */
077      Iterable<C> consume() throws IllegalStateException;
078    
079      /**
080       * Produce an item.
081       *
082       * @param product the item product
083       */
084      void produce(P product);
085    
086    }