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
020package org.crsh.shell;
021
022import org.crsh.keyboard.KeyHandler;
023
024/**
025 * A shell process.
026 */
027public interface ShellProcess {
028
029  /**
030   * Begin the process. The client of this method should make no assumption whether the process is executed
031   * in a synchronous or asynchronous manner. The process will be termined when the process signals it
032   * with an invocation of the {@link ShellProcessContext#end(ShellResponse)} method.
033   *
034   * @param processContext the process context
035   * @throws IllegalStateException if the process is already executing or has been executed
036   */
037  void execute(ShellProcessContext processContext) throws IllegalStateException;
038
039  /**
040   * Returns the key handler or null if the process won't handle key events.
041   *
042   * @return the key handler for this process
043   */
044  KeyHandler getKeyHandler() throws IllegalStateException;
045
046  /**
047   * Signals the process it should be cancelled. This method cannot be be called before the process has started,
048   * it can be called multiple times after the process has started. The cancellation of the process is asynchronous,
049   * the cancellation of the process will terminate the current context lifecycle by calling the
050   * {@link org.crsh.shell.ShellProcessContext#end(ShellResponse)} method.
051   *
052   * @throws IllegalStateException if the execution has not yet started
053   */
054  void cancel() throws IllegalStateException;
055
056}