Allow creating observables from AbstractButtons.

Author: jmhofer

extensions/rxjava-swing/src/main/java/rx/SwingObservable.java

@@ -0,0 +1,94 @@
+/**
+ * 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;
+
+import static org.mockito.Mockito.*;
+
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+
+import javax.swing.AbstractButton;
+
+import org.junit.Test;
+import org.mockito.Matchers;
+
+import rx.subscriptions.Subscriptions;
+import rx.util.functions.Action0;
+import rx.util.functions.Action1;
+import rx.util.functions.Func1;
+
+public enum SwingObservable { ; // no instances
+
+    public static Observable<ActionEvent> fromButtonAction(final AbstractButton button) {
+        return Observable.create(new Func1<Observer<ActionEvent>, Subscription>() {
+            @Override
+            public Subscription call(final Observer<ActionEvent> observer) {
+                final ActionListener listener = new ActionListener() {
+                    @Override
+                    public void actionPerformed(ActionEvent e) {
+                        observer.onNext(e);
+                    }
+                };
+                button.addActionListener(listener);
+                
+                return Subscriptions.create(new Action0() {
+                    @Override
+                    public void call() {
+                        button.removeActionListener(listener);
+                    }
+                });
+            }
+        });
+    }
+    
+    public static class UnitTest {
+        @Test
+        public void testObservingActionEvents() {
+            @SuppressWarnings("unchecked")
+            Action1<ActionEvent> action = mock(Action1.class);
+            @SuppressWarnings("unchecked")
+            Action1<Exception> error = mock(Action1.class);
+            Action0 complete = mock(Action0.class);
+            
+            final ActionEvent event = new ActionEvent(this, 1, "command");
+            
+            class TestButton extends AbstractButton {
+                void testAction() {
+                    fireActionPerformed(event);
+                }
+            }
+            
+            TestButton button = new TestButton();
+            Subscription sub = fromButtonAction(button).subscribe(action, error, complete);
+            
+            verify(action, never()).call(Matchers.<ActionEvent>any());
+            verify(error, never()).call(Matchers.<Exception>any());
+            verify(complete, never()).call();
+            
+            button.testAction();
+            verify(action, times(1)).call(Matchers.<ActionEvent>any());
+            
+            button.testAction();
+            verify(action, times(2)).call(Matchers.<ActionEvent>any());
+            
+            sub.unsubscribe();
+            button.testAction();
+            verify(action, times(2)).call(Matchers.<ActionEvent>any());
+            verify(error, never()).call(Matchers.<Exception>any());
+            verify(complete, never()).call();
+        }
+    }
+}