Add a CallServiceSelector base implementation

Add the base class for implementing CallServiceSelectors.

Change-Id: I292d962f1b73d0966af0c484ebddc724f8e6c925

telecomm/java/android/telecomm/CallServiceSelector.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2014 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.Binder;
+import android.os.IBinder;
+import android.os.RemoteException;
+
+import java.util.List;
+
+/**
+ * Allows for the organization of {@link CallService}s for outbound calls. Given a call and list of
+ * {@link CallService} IDs, order the list in terms of priority and return it using
+ * {@link #select(CallInfo, List)}. <br />
+ * <br />
+ * Also determine whether a call is switchable (can be moved between {@link CallService}s) or not
+ * using {@link #isSwitchable(CallInfo)}.
+ */
+public abstract class CallServiceSelector extends Service {
+
+    /** Manages the binder calls so that the implementor does not need to deal it. */
+    private final class CallServiceSelectorBinder extends ICallServiceSelector.Stub {
+        @Override
+        public void isSwitchable(CallInfo callInfo, ICallSwitchabilityResponse response)
+                throws RemoteException {
+            // Ensure that we're running with the app's normal permission level
+            long ident = Binder.clearCallingIdentity();
+            try {
+                response.setIsSwitchable(CallServiceSelector.this.isSwitchable(callInfo));
+            } finally {
+                Binder.restoreCallingIdentity(ident);
+            }
+        }
+
+        @Override
+        public void select(CallInfo callInfo, List<String> callServiceIds,
+                ICallServiceSelectionResponse response) throws RemoteException {
+            // Ensure that we're running with the app's normal permission level
+            long ident = Binder.clearCallingIdentity();
+            try {
+                response.setSelectedCallServiceIds(
+                        CallServiceSelector.this.select(callInfo, callServiceIds));
+            } finally {
+                Binder.restoreCallingIdentity(ident);
+            }
+        }
+    }
+
+    private final CallServiceSelectorBinder mBinder;
+
+    protected CallServiceSelector() {
+        mBinder = new CallServiceSelectorBinder();
+    }
+
+    @Override
+    public final IBinder onBind(Intent intent) {
+        return mBinder;
+    }
+
+    /**
+     * Determines (and returns) whether the given call is switchable. That is, whether the call can
+     * be moved to another {@link CallService} seamlessly.<br />
+     * <br />
+     * This method is not called on the UI thread and is safe to block.
+     *
+     * @param callInfo The call being potentially switched between {@link CallService}s.
+     * @return Whether the given call is switchable or not.
+     */
+    protected abstract boolean isSwitchable(CallInfo callInfo);
+
+    /**
+     * Return a list of prioritized {@link CallService}s which should be used to complete the given
+     * call.<br />
+     * <br />
+     * This method is not called on the UI thread and is safe to block.
+     *
+     * @param callInfo The call being placed using the {@link CallService}s.
+     * @param callServiceIds The IDs of the {@link CallService}s to organize for the call.
+     *
+     * @return A list of prioritized {@link CallService} IDs to use to complete the given call.
+     */
+    protected abstract List<String> select(CallInfo callInfo, List<String> callServiceIds);
+}