[sync] Add java InvalidationController for Android.

sync/android/java/src/org/chromium/sync/notifier/InvalidationController.java

Index: sync/android/java/src/org/chromium/sync/notifier/InvalidationController.java
diff --git a/sync/android/java/src/org/chromium/sync/notifier/InvalidationController.java b/sync/android/java/src/org/chromium/sync/notifier/InvalidationController.java
new file mode 100644
index 0000000000000000000000000000000000000000..9d5483e650893fd146e4f60ec8de3cdb029f5d2d
--- /dev/null
+++ b/sync/android/java/src/org/chromium/sync/notifier/InvalidationController.java
@@ -0,0 +1,180 @@
+// Copyright (c) 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.sync.notifier;
+
+import android.accounts.Account;
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageManager;
+import android.content.pm.PackageManager.NameNotFoundException;
+import android.util.Log;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.Lists;
+
+import org.chromium.sync.ModelType;
+
+import java.util.Set;
+
+import javax.annotation.Nullable;
+
+/**
+ * Controller used to send start, stop, and registration-change commands to the invalidation
+ * client library used by Sync.
+ */
+public class InvalidationController {
+    /**
+     * Constants and utility methods to create the intents used to communicate between the
+     * controller and the invalidation client library.
+     */
+    public static class IntentProtocol {
+        /**
+         * Action set on register intents.
+         */
+        public static final String ACTION_REGISTER =
+                "org.chromium.sync.notifier.ACTION_REGISTER_TYPES";
+        /**

[Yaron, 2013/01/10 19:29:40]

Nit: missing ws above

[nyquist, 2013/01/10 22:01:42]

Done.

+         * Special syncable type that lets us know to sync all types.
+         */
+        public static final String ALL_TYPES_TYPE = "ALL_TYPES";
+
+        /**
+         * Parcelable-valued intent extra containing the account of the user.
+         */
+        public static final String EXTRA_ACCOUNT = "account";
+
+        /**
+         * String-list-valued intent extra of the syncable types to sync.
+         */
+        public static final String EXTRA_REGISTERED_TYPES = "registered_types";
+
+        /**
+         * Boolean-valued intent extra indicating that the service should be stopped.
+         */
+        public static final String EXTRA_STOP = "stop";
+
+        /**
+         * Create an Intent that will start the invalidation listener service and
+         * register for the specified types.
+         */
+        public static Intent createRegisterIntent(Account account,
+                                                  boolean allTypes, Set<ModelType> types) {
+            Intent registerIntent = new Intent(ACTION_REGISTER);
+            String[] selectedTypesArray;
+            if (allTypes) {
+                selectedTypesArray = new String[]{ALL_TYPES_TYPE};
+            } else {
+                selectedTypesArray = new String[types.size()];
+                int pos = 0;
+                for (ModelType type : types) {
+                    selectedTypesArray[pos++] = type.name();
+                }
+            }
+            registerIntent.putStringArrayListExtra(EXTRA_REGISTERED_TYPES,
+                    Lists.newArrayList(selectedTypesArray));
+            registerIntent.putExtra(EXTRA_ACCOUNT, account);
+            return registerIntent;
+        }
+
+        private IntentProtocol() {
+            // Disallow instantiation.
+        }
+    }
+
+    /**
+     * Name of the manifest application metadata property specifying the name of the class
+     * implementing the invalidation client.
+     */
+    private static final String IMPL_CLASS_MANIFEST_PROPERTY =

[Yaron, 2013/01/10 19:29:40]

nit: IMPLEMENTING_CLASS_NAME? Seems like the brevity is hurting.

[nyquist, 2013/01/10 22:01:42]

Done.

+            "org.chromium.sync.notifier.IMPL_CLASS_NAME";
+
+    /**
+     * Logging tag.
+     */
+    private static final String TAG = InvalidationController.class.getSimpleName();
+
+    private final Context context;
+
+    /**
+     * Sets the types for which the client should register for notifications.
+     *
+     * @param account  Account of the user.
+     * @param allTypes If {@code true}, registers for all types, and {@code types} is ignored
+     * @param types    Set of types for which to register. Ignored if {@code allTypes == true}.
+     */
+    public void setRegisteredTypes(Account account, boolean allTypes, Set<ModelType> types) {
+        Intent registerIntent = IntentProtocol.createRegisterIntent(account, allTypes, types);
+        setDestinationClassName(registerIntent);
+        context.startService(registerIntent);
+    }
+
+    /**
+     * Starts the invalidation client.
+     */
+    public void start() {
+        Intent intent = setDestinationClassName(new Intent());
+        context.startService(intent);
+    }
+
+    /**
+     * Stops the invalidation client.
+     */
+    public void stop() {
+        Intent intent = setDestinationClassName(new Intent());
+        intent.putExtra(IntentProtocol.EXTRA_STOP, true);
+        context.startService(intent);
+    }
+
+    /**
+     * Returns the contract authority to use when requesting sync.
+     */
+    public String getContractAuthority() {
+        return context.getPackageName();
+    }
+
+    /**
+     * Returns a new instance that will use {@code context} to issue intents.
+     */
+    public static InvalidationController newInstance(Context context) {
+        return new InvalidationController(context);
+    }
+
+    /**
+     * Creates an instance using {@code context} to send intents.
+     */
+    private InvalidationController(Context context) {
+        this.context = Preconditions.checkNotNull(context.getApplicationContext());
+    }
+
+    /**
+     * Sets the destination class name of {@code intent} to the value given by the manifest
+     * property named {@link #IMPL_CLASS_MANIFEST_PROPERTY}. If no such property exists or its
+     * value is null, takes no action.
+     *
+     * @return {@code intent}
+     */
+    private Intent setDestinationClassName(Intent intent) {
+        @Nullable ApplicationInfo appInfo;

[Yaron, 2013/01/10 19:29:40]

We don't really make use of @Nullable elsewhere so it seems to be stylistically
at odds. Also, isn't it more useful as a formal argument? Here you're not
instantiating it so it's obvious.

[nyquist, 2013/01/10 22:01:42]

Done.

+        try {
+            // Fetch application info and read the appropriate metadata element.
+            appInfo = context.getPackageManager().getApplicationInfo(context.getPackageName(),
+                    PackageManager.GET_META_DATA);
+            @Nullable String className = null;

[Yaron, 2013/01/10 19:29:40]

same

[nyquist, 2013/01/10 22:01:42]

Done.

+            if (appInfo.metaData != null) {
+                className = appInfo.metaData.getString(IMPL_CLASS_MANIFEST_PROPERTY);
+            }
+            if (className == null) {
+                Log.wtf(TAG, "No value for " + IMPL_CLASS_MANIFEST_PROPERTY
+                        + " in manifest; sync notifications will not work");
+            } else {
+                intent.setClassName(context, className);
+            }
+        } catch (NameNotFoundException exception) {
+            Log.e(TAG, "Cannot read own application info", exception);

[Yaron, 2013/01/10 19:29:40]

THis is also a wtf moment?

[nyquist, 2013/01/10 22:01:42]

Done.

+        }
+        return intent;
+    }
+}