src/jexer/backend/HeadlessBackend.java

   1 /*
   2  * Jexer - Java Text User Interface
   3  *
   4  * The MIT License (MIT)
   5  *
   6  * Copyright (C) 2019 Kevin Lamonte
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a
   9  * copy of this software and associated documentation files (the "Software"),
  10  * to deal in the Software without restriction, including without limitation
  11  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  12  * and/or sell copies of the Software, and to permit persons to whom the
  13  * Software is furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  24  * DEALINGS IN THE SOFTWARE.
  25  *
  26  * @author Kevin Lamonte [kevin.lamonte@gmail.com]
  27  * @version 1
  28  */
  29 package jexer.backend;
  30
  31 import java.util.List;
  32
  33 import jexer.event.TInputEvent;
  34
  35 /**
  36  * HeadlessBackend
  37  */
  38 public class HeadlessBackend extends LogicalScreen implements Backend {
  39
  40     // ------------------------------------------------------------------------
  41     // Variables --------------------------------------------------------------
  42     // ------------------------------------------------------------------------
  43
  44     /**
  45      * The session information.
  46      */
  47     private SessionInfo sessionInfo;
  48
  49     // ------------------------------------------------------------------------
  50     // Constructors -----------------------------------------------------------
  51     // ------------------------------------------------------------------------
  52
  53     /**
  54      * Public constructor.
  55      */
  56     public HeadlessBackend() {
  57         sessionInfo = new TSessionInfo(width, height);
  58     }
  59
  60     // ------------------------------------------------------------------------
  61     // Backend ----------------------------------------------------------------
  62     // ------------------------------------------------------------------------
  63
  64     /**
  65      * Getter for sessionInfo.
  66      *
  67      * @return the SessionInfo
  68      */
  69     public final SessionInfo getSessionInfo() {
  70         return sessionInfo;
  71     }
  72
  73     /**
  74      * Get a Screen, which displays the text cells to the user.
  75      *
  76      * @return the Screen
  77      */
  78     public Screen getScreen() {
  79         return this;
  80     }
  81
  82     /**
  83      * Subclasses must provide an implementation that syncs the logical
  84      * screen to the physical device.
  85      */
  86     public void flushScreen() {
  87         // NOP
  88     }
  89
  90     /**
  91      * Check if there are events in the queue.
  92      *
  93      * @return if true, getEvents() has something to return to the application
  94      */
  95     public boolean hasEvents() {
  96         return false;
  97     }
  98
  99     /**
 100      * Subclasses must provide an implementation to get keyboard, mouse, and
 101      * screen resize events.
 102      *
 103      * @param queue list to append new events to
 104      */
 105     public void getEvents(List<TInputEvent> queue) {
 106         // NOP
 107     }
 108
 109     /**
 110      * Subclasses must provide an implementation that closes sockets,
 111      * restores console, etc.
 112      */
 113     public void shutdown() {
 114         // NOP
 115     }
 116
 117     /**
 118      * Set listener to a different Object.
 119      *
 120      * @param listener the new listening object that run() wakes up on new
 121      * input
 122      */
 123     public void setListener(final Object listener) {
 124         // NOP
 125     }
 126
 127     /**
 128      * Reload backend options from System properties.
 129      */
 130     public void reloadOptions() {
 131         // NOP
 132     }
 133
 134 }