src/jexer/backend/Backend.java

   1 /**
   2  * Jexer - Java Text User Interface
   3  *
   4  * License: LGPLv3 or later
   5  *
   6  * This module is licensed under the GNU Lesser General Public License
   7  * Version 3.  Please see the file "COPYING" in this directory for more
   8  * information about the GNU Lesser General Public License Version 3.
   9  *
  10  *     Copyright (C) 2015  Kevin Lamonte
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU Lesser General Public License
  14  * as published by the Free Software Foundation; either version 3 of
  15  * the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful, but
  18  * WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  * General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Lesser General Public
  23  * License along with this program; if not, see
  24  * http://www.gnu.org/licenses/, or write to the Free Software
  25  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  26  * 02110-1301 USA
  27  *
  28  * @author Kevin Lamonte [kevin.lamonte@gmail.com]
  29  * @version 1
  30  */
  31 package jexer.backend;
  32
  33 import java.util.List;
  34
  35 import jexer.event.TInputEvent;
  36 import jexer.io.Screen;
  37 import jexer.session.SessionInfo;
  38
  39 /**
  40  * This abstract class provides a screen, keyboard, and mouse to
  41  * TApplication.  It also exposes session information as gleaned from lower
  42  * levels of the communication stack.
  43  */
  44 public abstract class Backend {
  45
  46     /**
  47      * The session information.
  48      */
  49     protected SessionInfo sessionInfo;
  50
  51     /**
  52      * Getter for sessionInfo.
  53      *
  54      * @return the SessionInfo
  55      */
  56     public final SessionInfo getSessionInfo() {
  57         return sessionInfo;
  58     }
  59
  60     /**
  61      * The screen to draw on.
  62      */
  63     protected Screen screen;
  64
  65     /**
  66      * Getter for screen.
  67      *
  68      * @return the Screen
  69      */
  70     public final Screen getScreen() {
  71         return screen;
  72     }
  73
  74     /**
  75      * Subclasses must provide an implementation that syncs the logical
  76      * screen to the physical device.
  77      */
  78     public abstract void flushScreen();
  79
  80     /**
  81      * Subclasses must provide an implementation to get keyboard, mouse, and
  82      * screen resize events.
  83      *
  84      * @param queue list to append new events to
  85      * @param timeout maximum amount of time (in millis) to wait for an
  86      * event.  0 means to return immediately, i.e. perform a poll.
  87      */
  88     public abstract void getEvents(List<TInputEvent> queue, int timeout);
  89
  90     /**
  91      * Subclasses must provide an implementation that closes sockets,
  92      * restores console, etc.
  93      */
  94     public abstract void shutdown();
  95
  96 }