Merge pull request ReactiveX#254 from jmhofer/SwingScheduler

Swing scheduler

Author: benjchristensen

rxjava-contrib/rxjava-swing/build.gradle

@@ -0,0 +1,49 @@
+apply plugin: 'java'
+apply plugin: 'eclipse'
+apply plugin: 'idea'
+apply plugin: 'osgi'
+
+sourceCompatibility = JavaVersion.VERSION_1_6
+targetCompatibility = JavaVersion.VERSION_1_6
+
+dependencies {
+    compile project(':rxjava-core')
+    provided 'junit:junit:4.10'
+    provided 'org.mockito:mockito-core:1.8.5'
+}
+
+eclipse {
+  classpath {
+    // include 'provided' dependencies on the classpath
+    plusConfigurations += configurations.provided
+
+    downloadSources = true
+    downloadJavadoc = true
+  }
+}
+
+idea {
+	module {
+		// include 'provided' dependencies on the classpath
+		scopes.PROVIDED.plus += configurations.provided
+	}
+}
+
+javadoc {
+    options {
+        doclet = "org.benjchristensen.doclet.DocletExclude"
+        docletpath = [rootProject.file('./gradle/doclet-exclude.jar')]
+        stylesheetFile = rootProject.file('./gradle/javadocStyleSheet.css')
+        windowTitle = "RxJava Javadoc ${project.version}"
+    }
+    options.addStringOption('top').value = '<h2 class="title" style="padding-top:40px">RxJava</h2>'
+}
+
+jar {
+    manifest {
+        name = 'rxjava-swing'
+        instruction 'Bundle-Vendor', 'Netflix'
+        instruction 'Bundle-DocURL', 'https://github.com/Netflix/RxJava'
+        instruction 'Import-Package', '!org.junit,!junit.framework,!org.mockito.*,*'
+    }
+}

rxjava-contrib/rxjava-swing/src/main/java/rx/concurrency/SwingScheduler.java

@@ -0,0 +1,267 @@
+/**
+ * Copyright 2013 Netflix, Inc.
+ * 
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package rx.concurrency;
+
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.*;
+
+import java.awt.EventQueue;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicReference;
+
+import javax.swing.SwingUtilities;
+import javax.swing.Timer;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.mockito.InOrder;
+
+import rx.Scheduler;
+import rx.Subscription;
+import rx.subscriptions.CompositeSubscription;
+import rx.subscriptions.Subscriptions;
+import rx.util.functions.Action0;
+import rx.util.functions.Func0;
+import rx.util.functions.Func2;
+
+/**
+ * Executes work on the Swing UI thread. 
+ * This scheduler should only be used with actions that execute quickly.
+ */
+public final class SwingScheduler extends Scheduler {
+    private static final SwingScheduler INSTANCE = new SwingScheduler();
+
+    public static SwingScheduler getInstance() {
+        return INSTANCE;
+    }
+
+    private SwingScheduler() {
+    }
+
+    @Override
+    public <T> Subscription schedule(final T state, final Func2<Scheduler, T, Subscription> action) {
+        final AtomicReference<Subscription> sub = new AtomicReference<Subscription>();
+        EventQueue.invokeLater(new Runnable() {
+            @Override
+            public void run() {
+                sub.set(action.call(SwingScheduler.this, state));
+            }
+        });
+        return Subscriptions.create(new Action0() {
+            @Override
+            public void call() {
+                Subscription subscription = sub.get();
+                if (subscription != null) {
+                    subscription.unsubscribe();
+                }
+            }
+        });
+    }
+
+    @Override
+    public <T> Subscription schedule(final T state, final Func2<Scheduler, T, Subscription> action, long dueTime, TimeUnit unit) {
+        final AtomicReference<Subscription> sub = new AtomicReference<Subscription>();
+        long delay = unit.toMillis(dueTime); 
+        assertThatTheDelayIsValidForTheSwingTimer(delay);
+        
+        class ExecuteOnceAction implements ActionListener {
+            private Timer timer;
+            
+            private void setTimer(Timer timer) {
+                this.timer = timer;
+            }
+            
+            @Override
+            public void actionPerformed(ActionEvent e) {
+                timer.stop();
+                sub.set(action.call(SwingScheduler.this, state));
+            }
+        }
+        
+        ExecuteOnceAction executeOnce = new ExecuteOnceAction();
+        final Timer timer = new Timer((int) delay, executeOnce);
+        executeOnce.setTimer(timer);
+        timer.start();
+        
+        return Subscriptions.create(new Action0() {
+            @Override
+            public void call() {
+                timer.stop();
+                
+                Subscription subscription = sub.get();
+                if (subscription != null) {
+                    subscription.unsubscribe();
+                }
+            }
+        });
+    }
+
+    @Override
+    public <T> Subscription schedulePeriodically(T state, final Func2<Scheduler, T, Subscription> action, long initialDelay, long period, TimeUnit unit) {
+        final AtomicReference<Timer> timer = new AtomicReference<Timer>();
+        
+        final long delay = unit.toMillis(period); 
+        assertThatTheDelayIsValidForTheSwingTimer(delay);
+        
+        final CompositeSubscription subscriptions = new CompositeSubscription();
+        final Func2<Scheduler, T, Subscription> initialAction = new Func2<Scheduler, T, Subscription>() {
+              @Override
+              public Subscription call(final Scheduler scheduler, final T state0) {
+                  // start timer for periodic execution, collect subscriptions
+                  timer.set(new Timer((int) delay, new ActionListener() {
+                      @Override
+                      public void actionPerformed(ActionEvent e) {
+                          subscriptions.add(action.call(scheduler,  state0));
+                      }
+                  }));
+                  timer.get().start();
+                  
+                  return action.call(scheduler, state0);
+              }
+        };
+        subscriptions.add(schedule(state, initialAction, initialDelay, unit));
+        
+        subscriptions.add(Subscriptions.create(new Action0() {
+            @Override
+            public void call() {
+                // in addition to all the individual unsubscriptions, stop the timer on unsubscribing
+                Timer maybeTimer = timer.get();
+                if (maybeTimer != null) {
+                    maybeTimer.stop();
+                }
+            }
+        }));
+        
+        return subscriptions;
+    }
+
+    private static void assertThatTheDelayIsValidForTheSwingTimer(long delay) {
+        if (delay < 0 || delay > Integer.MAX_VALUE) {
+            throw new IllegalArgumentException(String.format("The swing timer only accepts non-negative delays up to %d milliseconds.", Integer.MAX_VALUE));
+        }
+    }
+    
+    public static class UnitTest {
+        @Rule
+        public ExpectedException exception = ExpectedException.none();
+        
+        @Test
+        public void testInvalidDelayValues() {
+            final SwingScheduler scheduler = new SwingScheduler();
+            final Action0 action = mock(Action0.class);
+
+            exception.expect(IllegalArgumentException.class);
+            scheduler.schedulePeriodically(action, -1L, 100L, TimeUnit.SECONDS);
+
+            exception.expect(IllegalArgumentException.class);
+            scheduler.schedulePeriodically(action, 100L, -1L, TimeUnit.SECONDS);
+
+            exception.expect(IllegalArgumentException.class);
+            scheduler.schedulePeriodically(action, 1L + Integer.MAX_VALUE, 100L, TimeUnit.MILLISECONDS);
+            
+            exception.expect(IllegalArgumentException.class);
+            scheduler.schedulePeriodically(action, 100L, 1L + Integer.MAX_VALUE / 1000, TimeUnit.SECONDS);
+        }
+        
+        @Test
+        public void testPeriodicScheduling() throws Exception {
+            final SwingScheduler scheduler = new SwingScheduler();
+
+            final Action0 innerAction = mock(Action0.class);
+            final Action0 unsubscribe = mock(Action0.class);
+            final Func0<Subscription> action = new Func0<Subscription>() {
+                @Override
+                public Subscription call() {
+                    innerAction.call();
+                    assertTrue(SwingUtilities.isEventDispatchThread());
+                    return Subscriptions.create(unsubscribe);
+                }
+            };
+            
+            Subscription sub = scheduler.schedulePeriodically(action, 50, 200, TimeUnit.MILLISECONDS);
+            Thread.sleep(840);
+            sub.unsubscribe();
+            waitForEmptyEventQueue();
+            verify(innerAction, times(4)).call();
+            verify(unsubscribe, times(4)).call();
+        }
+        
+        @Test
+        public void testNestedActions() throws Exception {
+            final SwingScheduler scheduler = new SwingScheduler();
+
+            final Action0 firstStepStart = mock(Action0.class);
+            final Action0 firstStepEnd = mock(Action0.class);
+
+            final Action0 secondStepStart = mock(Action0.class);
+            final Action0 secondStepEnd = mock(Action0.class);
+
+            final Action0 thirdStepStart = mock(Action0.class);
+            final Action0 thirdStepEnd = mock(Action0.class);
+
+            final Action0 firstAction = new Action0() {
+                @Override
+                public void call() {
+                    assertTrue(SwingUtilities.isEventDispatchThread());
+                    firstStepStart.call();
+                    firstStepEnd.call();
+                }
+            };
+            final Action0 secondAction = new Action0() {
+                @Override
+                public void call() {
+                    assertTrue(SwingUtilities.isEventDispatchThread());
+                    secondStepStart.call();
+                    scheduler.schedule(firstAction);
+                    secondStepEnd.call();
+                }
+            };
+            final Action0 thirdAction = new Action0() {
+                @Override
+                public void call() {
+                    assertTrue(SwingUtilities.isEventDispatchThread());
+                    thirdStepStart.call();
+                    scheduler.schedule(secondAction);
+                    thirdStepEnd.call();
+                }
+            };
+
+            InOrder inOrder = inOrder(firstStepStart, firstStepEnd, secondStepStart, secondStepEnd, thirdStepStart, thirdStepEnd);
+
+            scheduler.schedule(thirdAction);
+            waitForEmptyEventQueue();
+
+            inOrder.verify(thirdStepStart, times(1)).call();
+            inOrder.verify(thirdStepEnd, times(1)).call();
+            inOrder.verify(secondStepStart, times(1)).call();
+            inOrder.verify(secondStepEnd, times(1)).call();
+            inOrder.verify(firstStepStart, times(1)).call();
+            inOrder.verify(firstStepEnd, times(1)).call();
+        }
+
+        private static void waitForEmptyEventQueue() throws Exception {
+            EventQueue.invokeAndWait(new Runnable() {
+                @Override
+                public void run() {
+                    // nothing to do, we're just waiting here for the event queue to be emptied
+                }
+            });
+        }
+    }
+}

settings.gradle

@@ -3,4 +3,5 @@ include 'rxjava-core', \
 'language-adaptors:rxjava-groovy', \
 'language-adaptors:rxjava-jruby', \
 'language-adaptors:rxjava-clojure', \
-'language-adaptors:rxjava-scala'
+'language-adaptors:rxjava-scala', \
+'rxjava-contrib:rxjava-swing'