src/jexer/backend/ECMA48Backend.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.io.InputStream;
  34 import java.io.OutputStream;
  35 import java.io.UnsupportedEncodingException;
  36 import java.util.List;
  37
  38 import jexer.event.TInputEvent;
  39 import jexer.io.ECMA48Screen;
  40 import jexer.io.ECMA48Terminal;
  41
  42 /**
  43  * This class uses an xterm/ANSI X3.64/ECMA-48 type terminal to provide a
  44  * screen, keyboard, and mouse to TApplication.
  45  */
  46 public final class ECMA48Backend extends Backend {
  47
  48     /**
  49      * Input events are processed by this Terminal.
  50      */
  51     private ECMA48Terminal terminal;
  52
  53     /**
  54      * Public constructor.
  55      *
  56      * @param input an InputStream connected to the remote user, or null for
  57      * System.in.  If System.in is used, then on non-Windows systems it will
  58      * be put in raw mode; shutdown() will (blindly!) put System.in in cooked
  59      * mode.  input is always converted to a Reader with UTF-8 encoding.
  60      * @param output an OutputStream connected to the remote user, or null
  61      * for System.out.  output is always converted to a Writer with UTF-8
  62      * encoding.
  63      * @throws UnsupportedEncodingException if an exception is thrown when
  64      * creating the InputStreamReader
  65      */
  66     public ECMA48Backend(final InputStream input,
  67         final OutputStream output) throws UnsupportedEncodingException {
  68
  69         // Create a terminal and explicitly set stdin into raw mode
  70         terminal = new ECMA48Terminal(input, output);
  71
  72         // Keep the terminal's sessionInfo so that TApplication can see it
  73         sessionInfo = terminal.getSessionInfo();
  74
  75         // Create a screen
  76         screen = new ECMA48Screen(terminal);
  77
  78         // Clear the screen
  79         terminal.getOutput().write(terminal.clearAll());
  80         terminal.flush();
  81     }
  82
  83     /**
  84      * Sync the logical screen to the physical device.
  85      */
  86     @Override
  87     public void flushScreen() {
  88         screen.flushPhysical();
  89     }
  90
  91     /**
  92      * Get keyboard, mouse, and screen resize events.
  93      *
  94      * @param queue list to append new events to
  95      * @param timeout maximum amount of time (in millis) to wait for an
  96      * event.  0 means to return immediately, i.e. perform a poll.
  97      */
  98     @Override
  99     public void getEvents(final List<TInputEvent> queue, final int timeout) {
 100         if (timeout > 0) {
 101             // Try to sleep, let the terminal's input thread wake me up if
 102             // something came in.
 103             synchronized (terminal) {
 104                 try {
 105                     terminal.wait(timeout);
 106                     if (terminal.hasEvents()) {
 107                         // System.err.println("getEvents()");
 108                         terminal.getEvents(queue);
 109                     } else {
 110                         // If I got here, then I timed out.  Call
 111                         // terminal.getIdleEvents() to pick up stragglers
 112                         // like bare resize.
 113                         // System.err.println("getIdleEvents()");
 114                         terminal.getIdleEvents(queue);
 115                     }
 116                 } catch (InterruptedException e) {
 117                     // Spurious interrupt, pretend it was like a timeout.
 118                     // System.err.println("[interrupt] getEvents()");
 119                     terminal.getIdleEvents(queue);
 120                 }
 121             }
 122         } else {
 123             // Asking for a poll, go get it.
 124             // System.err.println("[polled] getEvents()");
 125             terminal.getEvents(queue);
 126         }
 127     }
 128
 129     /**
 130      * Close the I/O, restore the console, etc.
 131      */
 132     @Override
 133     public void shutdown() {
 134         terminal.shutdown();
 135     }
 136
 137 }