altosuilib: Hook up apple messages to callbacks

This supports open, quit and preferences. I'm leaving 'about' to the
existing stuff until I decide it's worth the effort to create a fancy
about dialog.

Signed-off-by: Keith Packard <keithp@keithp.com>

3 files changed, 253 insertions, 2 deletions

diff --git a/altosuilib/AltosUIFrame.java b/altosuilib/AltosUIFrame.java
index 689ea7f3..5b915e85 100644
--- a/altosuilib/AltosUIFrame.java
+++ b/altosuilib/AltosUIFrame.java
@@ -163,6 +163,50 @@ public class AltosUIFrame extends JFrame implements AltosUIListener, AltosPositi
 		return "Altus Metrum";
 	}
 
+	public void macosx_quit_handler() {
+		System.out.printf("Got quit handler\n");
+	}
+
+	public void macosx_about_handler() {
+		System.out.printf("Got about handler\n");
+	}
+
+	public void macosx_preferences_handler() {
+		System.out.printf("Got preferences handler\n");
+	}
+
+	public void macosx_file_handler(String path) {
+		System.out.printf("Got file handler with \"%s\"\n", path);
+	}
+
+	/* Check that we are on Mac OS X.  This is crucial to loading and using the OSXAdapter class.
+	 */
+	public static boolean MAC_OS_X = (System.getProperty("os.name").toLowerCase().startsWith("mac os x"));
+
+	private static boolean registered_for_macosx_events;
+
+	/* Generic registration with the Mac OS X application menu
+	 * Checks the platform, then attempts to register with the Apple EAWT
+	 * See OSXAdapter.java to see how this is done without directly referencing any Apple APIs
+	 */
+	public synchronized void register_for_macosx_events() {
+		if (registered_for_macosx_events)
+			return;
+		registered_for_macosx_events = true;
+		if (MAC_OS_X) {
+			try {
+				// Generate and register the OSXAdapter, passing it a hash of all the methods we wish to
+				// use as delegates for various com.apple.eawt.ApplicationListener methods
+				OSXAdapter.setQuitHandler(this, getClass().getDeclaredMethod("macosx_quit_handler", (Class[])null));
+//				OSXAdapter.setAboutHandler(this, getClass().getDeclaredMethod("macosx_about_handler", (Class[])null));
+				OSXAdapter.setPreferencesHandler(this, getClass().getDeclaredMethod("macosx_preferences_handler", (Class[])null));
+				OSXAdapter.setFileHandler(this, getClass().getDeclaredMethod("macosx_file_handler", new Class[] { String.class }));
+			} catch (Exception e) {
+				System.err.println("Error while loading the OSXAdapter:");
+				e.printStackTrace();
+			}
+		}
+	}
 	void init() {
 		AltosUIPreferences.register_ui_listener(this);
 		AltosUIPreferences.register_position_listener(this);
@@ -175,7 +219,7 @@ public class AltosUIFrame extends JFrame implements AltosUIListener, AltosPositi
 				global_settings_done = true;
 				System.setProperty("com.apple.mrj.application.apple.menu.about.name", getName());
 				System.setProperty("com.apple.macos.useScreenMenuBar", "true");
-				System.setProperty( "apple.laf.useScreenMenuBar", "true" ); // for older versions of Java
+				System.setProperty("apple.laf.useScreenMenuBar", "true" ); // for older versions of Java
 			} catch (Exception e) {
 			}
 		}
diff --git a/altosuilib/Makefile.am b/altosuilib/Makefile.am
index 157cd5e8..bbee6a45 100644
--- a/altosuilib/Makefile.am
+++ b/altosuilib/Makefile.am
@@ -81,7 +81,8 @@ altosuilib_JAVA = \
 	AltosUIIndicator.java \
 	AltosUIUnitsIndicator.java \
 	AltosUIVoltageIndicator.java \
-	AltosUITelemetryMenu.java
+	AltosUITelemetryMenu.java \
+	OSXAdapter.java
 
 JAR=altosuilib_$(ALTOSUILIB_VERSION).jar
 
diff --git a/altosuilib/OSXAdapter.java b/altosuilib/OSXAdapter.java
new file mode 100755
index 00000000..23aacd78
--- /dev/null
+++ b/altosuilib/OSXAdapter.java
@@ -0,0 +1,206 @@
+/*
+
+File: OSXAdapter.java
+
+Abstract: Hooks existing preferences/about/quit functionality from an
+    existing Java app into handlers for the Mac OS X application menu.
+    Uses a Proxy object to dynamically implement the
+    com.apple.eawt.ApplicationListener interface and register it with the
+    com.apple.eawt.Application object.  This allows the complete project
+    to be both built and run on any platform without any stubs or
+    placeholders. Useful for developers looking to implement Mac OS X
+    features while supporting multiple platforms with minimal impact.
+
+Version: 2.0
+
+Disclaimer: IMPORTANT:  This Apple software is supplied to you by
+Apple Inc. ("Apple") in consideration of your agreement to the
+following terms, and your use, installation, modification or
+redistribution of this Apple software constitutes acceptance of these
+terms.  If you do not agree with these terms, please do not use,
+install, modify or redistribute this Apple software.
+
+In consideration of your agreement to abide by the following terms, and
+subject to these terms, Apple grants you a personal, non-exclusive
+license, under Apple's copyrights in this original Apple software (the
+"Apple Software"), to use, reproduce, modify and redistribute the Apple
+Software, with or without modifications, in source and/or binary forms;
+provided that if you redistribute the Apple Software in its entirety and
+without modifications, you must retain this notice and the following
+text and disclaimers in all such redistributions of the Apple Software.
+Neither the name, trademarks, service marks or logos of Apple Inc.
+may be used to endorse or promote products derived from the Apple
+Software without specific prior written permission from Apple.  Except
+as expressly stated in this notice, no other rights or licenses, express
+or implied, are granted by Apple herein, including but not limited to
+any patent rights that may be infringed by your derivative works or by
+other works in which the Apple Software may be incorporated.
+
+The Apple Software is provided by Apple on an "AS IS" basis.  APPLE
+MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
+THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
+FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
+OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
+
+IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
+OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
+MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
+AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
+STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+
+Copyright © 2003-2007 Apple, Inc., All Rights Reserved
+
+*/
+
+package org.altusmetrum.altosuilib_3;
+
+import java.lang.reflect.*;
+import java.util.HashMap;
+
+
+public class OSXAdapter implements InvocationHandler {
+
+    protected Object targetObject;
+    protected Method targetMethod;
+    protected String proxySignature;
+
+    static Object macOSXApplication;
+
+    // Pass this method an Object and Method equipped to perform application shutdown logic
+    // The method passed should return a boolean stating whether or not the quit should occur
+    public static void setQuitHandler(Object target, Method quitHandler) {
+        setHandler(new OSXAdapter("handleQuit", target, quitHandler));
+    }
+
+    // Pass this method an Object and Method equipped to display application info
+    // They will be called when the About menu item is selected from the application menu
+    public static void setAboutHandler(Object target, Method aboutHandler) {
+        boolean enableAboutMenu = (target != null && aboutHandler != null);
+        if (enableAboutMenu) {
+            setHandler(new OSXAdapter("handleAbout", target, aboutHandler));
+        }
+        // If we're setting a handler, enable the About menu item by calling
+        // com.apple.eawt.Application reflectively
+        try {
+            Method enableAboutMethod = macOSXApplication.getClass().getDeclaredMethod("setEnabledAboutMenu", new Class[] { boolean.class });
+            enableAboutMethod.invoke(macOSXApplication, new Object[] { Boolean.valueOf(enableAboutMenu) });
+        } catch (Exception ex) {
+            System.err.println("OSXAdapter could not access the About Menu");
+            ex.printStackTrace();
+        }
+    }
+
+    // Pass this method an Object and a Method equipped to display application options
+    // They will be called when the Preferences menu item is selected from the application menu
+    public static void setPreferencesHandler(Object target, Method prefsHandler) {
+        boolean enablePrefsMenu = (target != null && prefsHandler != null);
+        if (enablePrefsMenu) {
+            setHandler(new OSXAdapter("handlePreferences", target, prefsHandler));
+        }
+        // If we're setting a handler, enable the Preferences menu item by calling
+        // com.apple.eawt.Application reflectively
+        try {
+            Method enablePrefsMethod = macOSXApplication.getClass().getDeclaredMethod("setEnabledPreferencesMenu", new Class[] { boolean.class });
+            enablePrefsMethod.invoke(macOSXApplication, new Object[] { Boolean.valueOf(enablePrefsMenu) });
+        } catch (Exception ex) {
+            System.err.println("OSXAdapter could not access the About Menu");
+            ex.printStackTrace();
+        }
+    }
+
+    // Pass this method an Object and a Method equipped to handle document events from the Finder
+    // Documents are registered with the Finder via the CFBundleDocumentTypes dictionary in the
+    // application bundle's Info.plist
+    public static void setFileHandler(Object target, Method fileHandler) {
+        setHandler(new OSXAdapter("handleOpenFile", target, fileHandler) {
+            // Override OSXAdapter.callTarget to send information on the
+            // file to be opened
+            public boolean callTarget(Object appleEvent) {
+                if (appleEvent != null) {
+                    try {
+                        Method getFilenameMethod = appleEvent.getClass().getDeclaredMethod("getFilename", (Class[])null);
+                        String filename = (String) getFilenameMethod.invoke(appleEvent, (Object[])null);
+                        this.targetMethod.invoke(this.targetObject, new Object[] { filename });
+                    } catch (Exception ex) {
+
+                    }
+                }
+                return true;
+            }
+        });
+    }
+
+    // setHandler creates a Proxy object from the passed OSXAdapter and adds it as an ApplicationListener
+    public static void setHandler(OSXAdapter adapter) {
+        try {
+            Class applicationClass = Class.forName("com.apple.eawt.Application");
+            if (macOSXApplication == null) {
+                macOSXApplication = applicationClass.getConstructor((Class[])null).newInstance((Object[])null);
+            }
+            Class applicationListenerClass = Class.forName("com.apple.eawt.ApplicationListener");
+            Method addListenerMethod = applicationClass.getDeclaredMethod("addApplicationListener", new Class[] { applicationListenerClass });
+            // Create a proxy object around this handler that can be reflectively added as an Apple ApplicationListener
+            Object osxAdapterProxy = Proxy.newProxyInstance(OSXAdapter.class.getClassLoader(), new Class[] { applicationListenerClass }, adapter);
+            addListenerMethod.invoke(macOSXApplication, new Object[] { osxAdapterProxy });
+        } catch (ClassNotFoundException cnfe) {
+            System.err.println("This version of Mac OS X does not support the Apple EAWT.  ApplicationEvent handling has been disabled (" + cnfe + ")");
+        } catch (Exception ex) {  // Likely a NoSuchMethodException or an IllegalAccessException loading/invoking eawt.Application methods
+            System.err.println("Mac OS X Adapter could not talk to EAWT:");
+            ex.printStackTrace();
+        }
+    }
+
+    // Each OSXAdapter has the name of the EAWT method it intends to listen for (handleAbout, for example),
+    // the Object that will ultimately perform the task, and the Method to be called on that Object
+    protected OSXAdapter(String proxySignature, Object target, Method handler) {
+        this.proxySignature = proxySignature;
+        this.targetObject = target;
+        this.targetMethod = handler;
+    }
+
+    // Override this method to perform any operations on the event
+    // that comes with the various callbacks
+    // See setFileHandler above for an example
+    public boolean callTarget(Object appleEvent) throws InvocationTargetException, IllegalAccessException {
+        Object result = targetMethod.invoke(targetObject, (Object[])null);
+        if (result == null) {
+            return true;
+        }
+        return Boolean.valueOf(result.toString()).booleanValue();
+    }
+
+    // InvocationHandler implementation
+    // This is the entry point for our proxy object; it is called every time an ApplicationListener method is invoked
+    public Object invoke (Object proxy, Method method, Object[] args) throws Throwable {
+        if (isCorrectMethod(method, args)) {
+            boolean handled = callTarget(args[0]);
+            setApplicationEventHandled(args[0], handled);
+        }
+        // All of the ApplicationListener methods are void; return null regardless of what happens
+        return null;
+    }
+
+    // Compare the method that was called to the intended method when the OSXAdapter instance was created
+    // (e.g. handleAbout, handleQuit, handleOpenFile, etc.)
+    protected boolean isCorrectMethod(Method method, Object[] args) {
+        return (targetMethod != null && proxySignature.equals(method.getName()) && args.length == 1);
+    }
+
+    // It is important to mark the ApplicationEvent as handled and cancel the default behavior
+    // This method checks for a boolean result from the proxy method and sets the event accordingly
+    protected void setApplicationEventHandled(Object event, boolean handled) {
+        if (event != null) {
+            try {
+                Method setHandledMethod = event.getClass().getDeclaredMethod("setHandled", new Class[] { boolean.class });
+                // If the target method returns a boolean, use that as a hint
+                setHandledMethod.invoke(event, new Object[] { Boolean.valueOf(handled) });
+            } catch (Exception ex) {
+                System.err.println("OSXAdapter was unable to handle an ApplicationEvent: " + event);
+                ex.printStackTrace();
+            }
+        }
+    }
+}