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 java.io.IOException;
023
024/**
025 * The interaction context extends the screen context and provides interaction with the client.
026 */
027public interface InteractionContext extends ScreenContext {
028
029  /**
030   * Take control of the alternate buffer. When the alternate buffer is already used
031   * nothing happens. The buffer switch should occur when then {@link #flush()} method
032   * is invoked.
033   *
034   * @return true if the alternate buffer is shown
035   */
036  boolean takeAlternateBuffer() throws IOException;
037
038  /**
039   * Release control of the alternate buffer. When the normal buffer is already used
040   * nothing happens. The buffer switch should occur when then {@link #flush()} method
041   * is invoked.
042   *
043   * @return true if the usual buffer is shown
044   */
045  boolean releaseAlternateBuffer() throws IOException;
046
047  /**
048   * Returns a generic property, usually this property is resolved by the
049   * shell client.
050   *
051   * @param propertyName the property name
052   * @return the property value
053   */
054  String getProperty(String propertyName);
055
056  /**
057   * Display a message and read a line on the console, this method call can be blocking until the user provides
058   * a value. If no line can be read then null is returned.
059   *
060   * @param msg the message to display before reading a line
061   * @param echo wether or not the line read should be echoed when typing
062   * @return the line read
063   * @throws java.io.IOException any io exception
064   * @throws java.lang.InterruptedException the thread was interrupted while waiting for the user value
065   * @throws java.lang.IllegalStateException if reading a line is not at the appropriate time
066   */
067  String readLine(String msg, boolean echo) throws IOException, InterruptedException, IllegalStateException;
068
069}