Simplify code relating to UI thread synchronization

* java/org/gnu/emacs/EmacsContextMenu.java (display):

* java/org/gnu/emacs/EmacsDialog.java (display):

* java/org/gnu/emacs/EmacsService.java (getEmacsView)
(getLocationOnScreen, getClipboardManager)
(requestDirectoryAccess): Replace manual synchronization within
Runnable objects by usage of FutureTask.
(syncRunnable): Accept FutureTask<V> in place of Runnables, and
obtain and return results from calls to its get method.

1 files changed, 10 insertions, 15 deletions

diff --git a/java/org/gnu/emacs/EmacsDialog.java b/java/org/gnu/emacs/EmacsDialog.java
index bad1ddde227..7552b16b370 100644
--- a/java/org/gnu/emacs/EmacsDialog.java
+++ b/java/org/gnu/emacs/EmacsDialog.java
@@ -22,6 +22,9 @@ package org.gnu.emacs;
 import java.util.List;
 import java.util.ArrayList;
 
+import java.util.concurrent.Callable;
+import java.util.concurrent.FutureTask;
+
 import android.app.AlertDialog;
 
 import android.content.Context;
@@ -388,26 +391,18 @@ public final class EmacsDialog implements DialogInterface.OnDismissListener
   public boolean
   display ()
   {
-    Runnable runnable;
-    final EmacsHolder<Boolean> rc;
+    FutureTask<Boolean> task;
 
-    rc = new EmacsHolder<Boolean> ();
-    rc.thing = false;
-    runnable = new Runnable () {
+    task = new FutureTask<Boolean> (new Callable<Boolean> () {
 	@Override
-	public void
-	run ()
+	public Boolean
+	call ()
 	{
-	  synchronized (this)
-	    {
-	      rc.thing = display1 ();
-	      notify ();
-	    }
+	  return display1 ();
 	}
-      };
+      });
 
-    EmacsService.syncRunnable (runnable);
-    return rc.thing;
+    return EmacsService.<Boolean>syncRunnable (task);
   }