Add 'src/jexer/' from commit 'cf01c92f5809a0732409e280fb0f32f27393618d'

[fanfix.git] / src / jexer / backend / GenericBackend.java

diff --git a/src/jexer/backend/GenericBackend.java b/src/jexer/backend/GenericBackend.java
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+/*
+ * Jexer - Java Text User Interface
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (C) 2019 Kevin Lamonte
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * @author Kevin Lamonte [kevin.lamonte@gmail.com]
+ * @version 1
+ */
+package jexer.backend;
+
+import java.util.List;
+
+import jexer.event.TInputEvent;
+import jexer.event.TCommandEvent;
+import static jexer.TCommand.*;
+
+/**
+ * This abstract class provides a screen, keyboard, and mouse to
+ * TApplication.  It also exposes session information as gleaned from lower
+ * levels of the communication stack.
+ */
+public abstract class GenericBackend implements Backend {
+
+    // ------------------------------------------------------------------------
+    // Variables --------------------------------------------------------------
+    // ------------------------------------------------------------------------
+
+    /**
+     * The session information.
+     */
+    protected SessionInfo sessionInfo;
+
+    /**
+     * The screen to draw on.
+     */
+    protected Screen screen;
+
+    /**
+     * Input events are processed by this Terminal.
+     */
+    protected TerminalReader terminal;
+
+    /**
+     * By default, GenericBackend adds a cmAbort after it sees
+     * cmBackendDisconnect, so that TApplication will exit when the user
+     * closes the Swing window or disconnects the ECMA48 streams.  But
+     * MultiBackend wraps multiple Backends, and needs to decide when to send
+     * cmAbort differently.  Setting this to false is how it manages that.
+     * Note package private access.
+     */
+    boolean abortOnDisconnect = true;
+
+    // ------------------------------------------------------------------------
+    // Constructors -----------------------------------------------------------
+    // ------------------------------------------------------------------------
+
+    // ------------------------------------------------------------------------
+    // Backend ----------------------------------------------------------------
+    // ------------------------------------------------------------------------
+
+    /**
+     * Getter for sessionInfo.
+     *
+     * @return the SessionInfo
+     */
+    public final SessionInfo getSessionInfo() {
+        return sessionInfo;
+    }
+
+    /**
+     * Getter for screen.
+     *
+     * @return the Screen
+     */
+    public final Screen getScreen() {
+        return screen;
+    }
+
+    /**
+     * Sync the logical screen to the physical device.
+     */
+    public void flushScreen() {
+        screen.flushPhysical();
+    }
+
+    /**
+     * Check if there are events in the queue.
+     *
+     * @return if true, getEvents() has something to return to the application
+     */
+    public boolean hasEvents() {
+        return terminal.hasEvents();
+    }
+
+    /**
+     * Get keyboard, mouse, and screen resize events.
+     *
+     * @param queue list to append new events to
+     */
+    public void getEvents(final List<TInputEvent> queue) {
+        if (terminal.hasEvents()) {
+            terminal.getEvents(queue);
+
+            // This default backend assumes a single user, and if that user
+            // becomes disconnected we should terminate the application.
+            if ((queue.size() > 0) && (abortOnDisconnect == true)) {
+                TInputEvent event = queue.get(queue.size() - 1);
+                if (event instanceof TCommandEvent) {
+                    TCommandEvent command = (TCommandEvent) event;
+                    if (command.equals(cmBackendDisconnect)) {
+                        queue.add(new TCommandEvent(cmAbort));
+                    }
+                }
+            }
+        }
+    }
+
+    /**
+     * Close the I/O, restore the console, etc.
+     */
+    public void shutdown() {
+        terminal.closeTerminal();
+    }
+
+    /**
+     * Set the window title.
+     *
+     * @param title the new title
+     */
+    public void setTitle(final String title) {
+        screen.setTitle(title);
+    }
+
+    /**
+     * Set listener to a different Object.
+     *
+     * @param listener the new listening object that run() wakes up on new
+     * input
+     */
+    public void setListener(final Object listener) {
+        terminal.setListener(listener);
+    }
+
+    /**
+     * Reload backend options from System properties.
+     */
+    public void reloadOptions() {
+        terminal.reloadOptions();
+    }
+
+}