Add a default CallServiceProvider implementation.

Change-Id: Ib9afcaac2e971fc8cd9d1fdef2d6ae97cbb79757

telecomm/java/android/telecomm/CallServiceProvider.java

@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * 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 android.telecomm;
+
+import android.app.Service;
+import android.content.Intent;
+import android.os.Handler;
+import android.os.IBinder;
+import android.os.Message;
+
+import android.telecomm.ICallServiceProvider;
+
+/**
+ * Base implementation of CallServiceProvider service which implements ICallServiceProvider.
+ * Its primary function is to provide implementations of {@link ICallService} which itself
+ * can be used to provide calls for the framework's telecomm component.
+ *
+ * TODO(santoscordon): Improve paragraph above once the final design is in place. Needs more
+ * about how this can be used.
+ * @hide
+ */
+public abstract class CallServiceProvider extends Service {
+
+    /**
+     * Default Handler used to consolidate binder method calls onto a single thread.
+     */
+    private final class CallServiceProviderMessageHandler extends Handler {
+        @Override
+        public void handleMessage(Message msg) {
+            switch (msg.what) {
+                case MSG_SET_CALL_SERVICE_PROVIDER_ADAPTER:
+                    setCallServiceProviderAdapter((ICallServiceProviderAdapter) msg.obj);
+                    break;
+                default:
+                    break;
+            }
+        }
+    }
+
+    /**
+     * Default ICallServiceProvider implementation provided to CallsManager via {@link #onBind}.
+     */
+    private final class CallServiceProviderWrapper extends ICallServiceProvider.Stub {
+        @Override
+        public void setCallServiceProviderAdapter(
+                ICallServiceProviderAdapter CallServiceProviderAdapter) {
+            mMessageHandler.obtainMessage(MSG_SET_CALL_SERVICE_PROVIDER_ADAPTER,
+                    CallServiceProviderAdapter).sendToTarget();
+        }
+
+        @Override
+        public void initiateDiscoveryProtocol() {}
+    }
+
+    // Only used internally by this class.
+    // Binder method calls on this service can occur on multiple threads. These messages are used
+    // in conjunction with {@link #mMessageHandler} to ensure that all callbacks are handled on a
+    // single thread.  Keeping it on a single thread allows CallService implementations to avoid
+    // needing multi-threaded code in their own callback routines.
+    private static final int MSG_SET_CALL_SERVICE_PROVIDER_ADAPTER = 1;
+
+    /**
+     * Message handler for consolidating binder callbacks onto a single thread.
+     * See {@link #CallServiceProviderMessageHandler}.
+     */
+    private final CallServiceProviderMessageHandler mMessageHandler;
+
+    /**
+     * Default binder implementation of {@link ICallServiceProvider} interface.
+     */
+    private final CallServiceProviderWrapper mBinder;
+
+    /**
+     * Protected constructor called only by subclasses creates the binder interface and
+     * single-threaded message handler.
+     */
+    protected CallServiceProvider() {
+        mMessageHandler = new CallServiceProviderMessageHandler();
+        mBinder = new CallServiceProviderWrapper();
+    }
+
+    /** {@inheritDoc} */
+    public IBinder onBind(Intent intent) {
+        return mBinder;
+    }
+
+    /**
+     * Sets an implementation of ICallServiceProviderAdapter for adding providing instances of
+     * ICallService.
+     * TODO(santoscordon): Should we not reference ICallServiceProviderAdapter directly from here?
+     * Should we wrap that in a wrapper like we do for CallServiceProvider/ICallServiceProvider?
+     * @param callServiceAdapter Adapter object for communicating call to CallsManager
+     */
+    public abstract void setCallServiceProviderAdapter(
+            ICallServiceProviderAdapter CallServiceProviderAdapter);
+}