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.text.ScreenContext;
023
024import java.io.IOException;
025
026/**
027 * The interaction context extends the screen context and provides interaction with the client.
028 */
029public interface InteractionContext extends ScreenContext {
030
031  /**
032   * Take control of the alternate buffer. When the alternate buffer is already used
033   * nothing happens. The buffer switch should occur when then {@link #flush()} method
034   * is invoked.
035   *
036   * @return true if the alternate buffer is shown
037   */
038  boolean takeAlternateBuffer() throws IOException;
039
040  /**
041   * Release control of the alternate buffer. When the normal buffer is already used
042   * nothing happens. The buffer switch should occur when then {@link #flush()} method
043   * is invoked.
044   *
045   * @return true if the usual buffer is shown
046   */
047  boolean releaseAlternateBuffer() throws IOException;
048
049  /**
050   * Returns a generic property, usually this property is resolved by the
051   * shell client.
052   *
053   * @param propertyName the property name
054   * @return the property value
055   */
056  String getProperty(String propertyName);
057
058  /**
059   * Display a message and read a line on the console, this method call can be blocking until the user provides
060   * a value. If no line can be read then null is returned.
061   *
062   * @param msg the message to display before reading a line
063   * @param echo wether or not the line read should be echoed when typing
064   * @return the line read
065   * @throws java.io.IOException any io exception
066   * @throws java.lang.InterruptedException the thread was interrupted while waiting for the user value
067   * @throws java.lang.IllegalStateException if reading a line is not at the appropriate time
068   */
069  String readLine(String msg, boolean echo) throws IOException, InterruptedException, IllegalStateException;
070
071}