Add basic Bluetooth LE advertising and scan support. (#47)

* Add basic Bluetooth LE advertising and scan support.
* Introduce `RpcEnum`, a standard way to handle String-int enum conversion.

8 files changed, 618 insertions, 57 deletions

diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothAdapterSnippet.java b/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothAdapterSnippet.java
index 67df97b..0f4d3e6 100644
--- a/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothAdapterSnippet.java
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothAdapterSnippet.java
@@ -23,6 +23,7 @@ import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.os.Build;
+import android.os.Bundle;
 import android.support.test.InstrumentationRegistry;
 import com.google.android.mobly.snippet.Snippet;
 import com.google.android.mobly.snippet.bundled.utils.JsonSerializer;
@@ -173,11 +174,11 @@ public class BluetoothAdapterSnippet implements Snippet {
     }
 
     @Rpc(description = "Get the list of paired bluetooth devices.")
-    public JSONArray btGetPairedDevices()
+    public ArrayList<Bundle> btGetPairedDevices()
             throws BluetoothAdapterSnippetException, InterruptedException, JSONException {
-        JSONArray pairedDevices = new JSONArray();
+        ArrayList<Bundle> pairedDevices = new ArrayList<>();
         for (BluetoothDevice device : mBluetoothAdapter.getBondedDevices()) {
-            pairedDevices.put(mJsonSerializer.toJson(device));
+            pairedDevices.add(mJsonSerializer.serializeBluetoothDevice(device));
         }
         return pairedDevices;
     }
diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothLeAdvertiserSnippet.java b/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothLeAdvertiserSnippet.java
new file mode 100644
index 0000000..e161a5b
--- /dev/null
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothLeAdvertiserSnippet.java
@@ -0,0 +1,178 @@
+/*
+ * Copyright (C) 2017 Google 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 com.google.android.mobly.snippet.bundled;
+
+import android.annotation.TargetApi;
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.le.AdvertiseCallback;
+import android.bluetooth.le.AdvertiseData;
+import android.bluetooth.le.AdvertiseSettings;
+import android.bluetooth.le.BluetoothLeAdvertiser;
+import android.os.Build;
+import android.os.Bundle;
+import android.os.ParcelUuid;
+import com.google.android.mobly.snippet.Snippet;
+import com.google.android.mobly.snippet.bundled.utils.JsonDeserializer;
+import com.google.android.mobly.snippet.bundled.utils.JsonSerializer;
+import com.google.android.mobly.snippet.bundled.utils.RpcEnum;
+import com.google.android.mobly.snippet.event.EventCache;
+import com.google.android.mobly.snippet.event.SnippetEvent;
+import com.google.android.mobly.snippet.rpc.AsyncRpc;
+import com.google.android.mobly.snippet.rpc.Rpc;
+import com.google.android.mobly.snippet.rpc.RpcMinSdk;
+import com.google.android.mobly.snippet.util.Log;
+import java.util.HashMap;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+/** Snippet class exposing Android APIs in WifiManager. */
+@TargetApi(Build.VERSION_CODES.LOLLIPOP_MR1)
+public class BluetoothLeAdvertiserSnippet implements Snippet {
+    private static class BluetoothLeAdvertiserSnippetException extends Exception {
+        private static final long serialVersionUID = 1;
+
+        public BluetoothLeAdvertiserSnippetException(String msg) {
+            super(msg);
+        }
+    }
+
+    private final BluetoothLeAdvertiser mAdvertiser;
+    private static final EventCache sEventCache = EventCache.getInstance();
+
+    private final HashMap<String, AdvertiseCallback> mAdvertiseCallbacks = new HashMap<>();
+
+    public BluetoothLeAdvertiserSnippet() {
+        mAdvertiser = BluetoothAdapter.getDefaultAdapter().getBluetoothLeAdvertiser();
+    }
+
+    /**
+     * Start Bluetooth LE advertising.
+     *
+     * <p>This can be called multiple times, and each call is associated with a {@link
+     * AdvertiseCallback} object, which is used to stop the advertising.
+     *
+     * @param callbackId
+     * @param advertiseSettings A JSONObject representing a {@link AdvertiseSettings object}. E.g.
+     *     <pre>
+     *          {
+     *            "AdvertiseMode": "ADVERTISE_MODE_BALANCED",
+     *            "Timeout": (int, milliseconds),
+     *            "Connectable": (bool),
+     *            "TxPowerLevel": "ADVERTISE_TX_POWER_LOW"
+     *          }
+     *     </pre>
+     *
+     * @param advertiseData A JSONObject representing a {@link AdvertiseData} object. E.g.
+     *     <pre>
+     *          {
+     *            "IncludeDeviceName": (bool),
+     *            # JSON list, each element representing a set of service data, which is composed of
+     *            # a UUID, and an optional string.
+     *            "ServiceData": [
+     *                      {
+     *                        "UUID": (A string representation of {@link ParcelUuid}),
+     *                        "Data": (Optional, The string representation of what you want to
+     *                                 advertise, base64 encoded)
+     *                        # If you want to add a UUID without data, simply omit the "Data"
+     *                        # field.
+     *                      }
+     *                ]
+     *          }
+     *     </pre>
+     *
+     * @throws BluetoothLeAdvertiserSnippetException
+     * @throws JSONException
+     */
+    @RpcMinSdk(Build.VERSION_CODES.LOLLIPOP_MR1)
+    @AsyncRpc(description = "Start BLE advertising.")
+    public void bleStartAdvertising(
+            String callbackId, JSONObject advertiseSettings, JSONObject advertiseData)
+            throws BluetoothLeAdvertiserSnippetException, JSONException {
+        if (!BluetoothAdapter.getDefaultAdapter().isEnabled()) {
+            throw new BluetoothLeAdvertiserSnippetException(
+                    "Bluetooth is disabled, cannot start BLE advertising.");
+        }
+        AdvertiseSettings settings = JsonDeserializer.jsonToBleAdvertiseSettings(advertiseSettings);
+        AdvertiseData data = JsonDeserializer.jsonToBleAdvertiseData(advertiseData);
+        AdvertiseCallback advertiseCallback = new DefaultAdvertiseCallback(callbackId);
+        mAdvertiser.startAdvertising(settings, data, advertiseCallback);
+        mAdvertiseCallbacks.put(callbackId, advertiseCallback);
+    }
+
+    /**
+     * Stop a BLE advertising.
+     *
+     * @param callbackId The callbackId corresponding to the {@link
+     *     BluetoothLeAdvertiserSnippet#bleStartAdvertising} call that started the advertising.
+     * @throws BluetoothLeScannerSnippet.BluetoothLeScanSnippetException
+     */
+    @RpcMinSdk(Build.VERSION_CODES.LOLLIPOP_MR1)
+    @Rpc(description = "Stop BLE advertising.")
+    public void bleStopAdvertising(String callbackId) throws BluetoothLeAdvertiserSnippetException {
+        AdvertiseCallback callback = mAdvertiseCallbacks.remove(callbackId);
+        if (callback == null) {
+            throw new BluetoothLeAdvertiserSnippetException(
+                    "No advertising session found for ID " + callbackId);
+        }
+        mAdvertiser.stopAdvertising(callback);
+    }
+
+    private static class DefaultAdvertiseCallback extends AdvertiseCallback {
+        private final String mCallbackId;
+        public static RpcEnum ADVERTISE_FAILURE_ERROR_CODE =
+                new RpcEnum.Builder()
+                        .add("ADVERTISE_FAILED_ALREADY_STARTED", ADVERTISE_FAILED_ALREADY_STARTED)
+                        .add("ADVERTISE_FAILED_DATA_TOO_LARGE", ADVERTISE_FAILED_DATA_TOO_LARGE)
+                        .add(
+                                "ADVERTISE_FAILED_FEATURE_UNSUPPORTED",
+                                ADVERTISE_FAILED_FEATURE_UNSUPPORTED)
+                        .add("ADVERTISE_FAILED_INTERNAL_ERROR", ADVERTISE_FAILED_INTERNAL_ERROR)
+                        .add(
+                                "ADVERTISE_FAILED_TOO_MANY_ADVERTISERS",
+                                ADVERTISE_FAILED_TOO_MANY_ADVERTISERS)
+                        .build();
+
+        public DefaultAdvertiseCallback(String callbackId) {
+            mCallbackId = callbackId;
+        }
+
+        public void onStartSuccess(AdvertiseSettings settingsInEffect) {
+            Log.e("Bluetooth LE advertising started with settings: " + settingsInEffect.toString());
+            SnippetEvent event = new SnippetEvent(mCallbackId, "onStartSuccess");
+            Bundle advertiseSettings =
+                    JsonSerializer.serializeBleAdvertisingSettings(settingsInEffect);
+            event.getData().putBundle("SettingsInEffect", advertiseSettings);
+            sEventCache.postEvent(event);
+        }
+
+        public void onStartFailure(int errorCode) {
+            Log.e("Bluetooth LE advertising failed to start with error code: " + errorCode);
+            SnippetEvent event = new SnippetEvent(mCallbackId, "onStartFailure");
+            final String errorCodeString = ADVERTISE_FAILURE_ERROR_CODE.getString(errorCode);
+            event.getData().putString("ErrorCode", errorCodeString);
+            sEventCache.postEvent(event);
+        }
+    }
+
+    @Override
+    public void shutdown() {
+        for (AdvertiseCallback callback : mAdvertiseCallbacks.values()) {
+            mAdvertiser.stopAdvertising(callback);
+        }
+        mAdvertiseCallbacks.clear();
+    }
+}
diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothLeScannerSnippet.java b/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothLeScannerSnippet.java
new file mode 100644
index 0000000..7e133d1
--- /dev/null
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/BluetoothLeScannerSnippet.java
@@ -0,0 +1,138 @@
+/*
+ * Copyright (C) 2017 Google 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 com.google.android.mobly.snippet.bundled;
+
+import android.annotation.TargetApi;
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.le.BluetoothLeScanner;
+import android.bluetooth.le.ScanCallback;
+import android.bluetooth.le.ScanResult;
+import android.os.Build;
+import android.os.Bundle;
+import com.google.android.mobly.snippet.Snippet;
+import com.google.android.mobly.snippet.bundled.utils.JsonSerializer;
+import com.google.android.mobly.snippet.bundled.utils.MbsEnums;
+import com.google.android.mobly.snippet.event.EventCache;
+import com.google.android.mobly.snippet.event.SnippetEvent;
+import com.google.android.mobly.snippet.rpc.AsyncRpc;
+import com.google.android.mobly.snippet.rpc.Rpc;
+import com.google.android.mobly.snippet.rpc.RpcMinSdk;
+import com.google.android.mobly.snippet.util.Log;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+
+/** Snippet class exposing Android APIs in WifiManager. */
+@TargetApi(Build.VERSION_CODES.LOLLIPOP_MR1)
+public class BluetoothLeScannerSnippet implements Snippet {
+    private static class BluetoothLeScanSnippetException extends Exception {
+        private static final long serialVersionUID = 1;
+
+        public BluetoothLeScanSnippetException(String msg) {
+            super(msg);
+        }
+    }
+
+    private final BluetoothLeScanner mScanner;
+    private final EventCache mEventCache = EventCache.getInstance();
+    private final HashMap<String, ScanCallback> mScanCallbacks = new HashMap<>();
+    private final JsonSerializer mJsonSerializer = new JsonSerializer();
+
+    public BluetoothLeScannerSnippet() {
+        mScanner = BluetoothAdapter.getDefaultAdapter().getBluetoothLeScanner();
+    }
+
+    /**
+     * Start a BLE scan.
+     *
+     * @param callbackId
+     * @throws BluetoothLeScanSnippetException
+     */
+    @RpcMinSdk(Build.VERSION_CODES.LOLLIPOP_MR1)
+    @AsyncRpc(description = "Start BLE scan.")
+    public void bleStartScan(String callbackId) throws BluetoothLeScanSnippetException {
+        if (!BluetoothAdapter.getDefaultAdapter().isEnabled()) {
+            throw new BluetoothLeScanSnippetException(
+                    "Bluetooth is disabled, cannot start BLE scan.");
+        }
+        DefaultScanCallback callback = new DefaultScanCallback(callbackId);
+        mScanner.startScan(callback);
+        mScanCallbacks.put(callbackId, callback);
+    }
+
+    /**
+     * Stop a BLE scan.
+     *
+     * @param callbackId The callbackId corresponding to the {@link
+     *     BluetoothLeScannerSnippet#bleStartScan} call that started the scan.
+     * @throws BluetoothLeScanSnippetException
+     */
+    @RpcMinSdk(Build.VERSION_CODES.LOLLIPOP_MR1)
+    @Rpc(description = "Stop a BLE scan.")
+    public void bleStopScan(String callbackId) throws BluetoothLeScanSnippetException {
+        ScanCallback callback = mScanCallbacks.remove(callbackId);
+        if (callback == null) {
+            throw new BluetoothLeScanSnippetException("No ongoing scan with ID: " + callbackId);
+        }
+        mScanner.stopScan(callback);
+    }
+
+    @Override
+    public void shutdown() {
+        for (ScanCallback callback : mScanCallbacks.values()) {
+            mScanner.stopScan(callback);
+        }
+        mScanCallbacks.clear();
+    }
+
+    private class DefaultScanCallback extends ScanCallback {
+        private final String mCallbackId;
+
+        public DefaultScanCallback(String callbackId) {
+            mCallbackId = callbackId;
+        }
+
+        public void onScanResult(int callbackType, ScanResult result) {
+            Log.i("Got Bluetooth LE scan result.");
+            SnippetEvent event = new SnippetEvent(mCallbackId, "onScanResult");
+            String callbackTypeString =
+                    MbsEnums.BLE_SCAN_RESULT_CALLBACK_TYPE.getString(callbackType);
+            event.getData().putString("CallbackType", callbackTypeString);
+            event.getData().putBundle("result", mJsonSerializer.serializeBleScanResult(result));
+            mEventCache.postEvent(event);
+        }
+
+        public void onBatchScanResults(List<ScanResult> results) {
+            Log.i("Got Bluetooth LE batch scan results.");
+            SnippetEvent event = new SnippetEvent(mCallbackId, "onBatchScanResult");
+            ArrayList<Bundle> resultList = new ArrayList<>(results.size());
+            for (ScanResult result : results) {
+                resultList.add(mJsonSerializer.serializeBleScanResult(result));
+            }
+            event.getData().putParcelableArrayList("results", resultList);
+            mEventCache.postEvent(event);
+        }
+
+        public void onScanFailed(int errorCode) {
+            Log.e("Bluetooth LE scan failed with error code: " + errorCode);
+            SnippetEvent event = new SnippetEvent(mCallbackId, "onScanFailed");
+            String errorCodeString = MbsEnums.BLE_SCAN_FAILED_ERROR_CODE.getString(errorCode);
+            event.getData().putString("ErrorCode", errorCodeString);
+            mEventCache.postEvent(event);
+        }
+    }
+}
diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonDeserializer.java b/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonDeserializer.java
index 4fc6b82..2f943e0 100644
--- a/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonDeserializer.java
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonDeserializer.java
@@ -16,7 +16,14 @@
 
 package com.google.android.mobly.snippet.bundled.utils;
 
+import android.annotation.TargetApi;
+import android.bluetooth.le.AdvertiseData;
+import android.bluetooth.le.AdvertiseSettings;
 import android.net.wifi.WifiConfiguration;
+import android.os.Build;
+import android.os.ParcelUuid;
+import android.util.Base64;
+import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;
 
@@ -40,4 +47,58 @@ public class JsonDeserializer {
         }
         return config;
     }
+
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    public static AdvertiseSettings jsonToBleAdvertiseSettings(JSONObject jsonObject)
+            throws JSONException {
+        AdvertiseSettings.Builder builder = new AdvertiseSettings.Builder();
+        if (jsonObject.has("AdvertiseMode")) {
+            int mode = MbsEnums.BLE_ADVERTISE_MODE.getInt(jsonObject.getString("AdvertiseMode"));
+            builder.setAdvertiseMode(mode);
+        }
+        // Timeout in milliseconds.
+        if (jsonObject.has("Timeout")) {
+            builder.setTimeout(jsonObject.getInt("Timeout"));
+        }
+        if (jsonObject.has("Connectable")) {
+            builder.setConnectable(jsonObject.getBoolean("Connectable"));
+        }
+        if (jsonObject.has("TxPowerLevel")) {
+            int txPowerLevel =
+                    MbsEnums.BLE_ADVERTISE_TX_POWER.getInt(jsonObject.getString("TxPowerLevel"));
+            builder.setTxPowerLevel(txPowerLevel);
+        }
+        return builder.build();
+    }
+
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    public static AdvertiseData jsonToBleAdvertiseData(JSONObject jsonObject) throws JSONException {
+        AdvertiseData.Builder builder = new AdvertiseData.Builder();
+        if (jsonObject.has("IncludeDeviceName")) {
+            builder.setIncludeDeviceName(jsonObject.getBoolean("IncludeDeviceName"));
+        }
+        if (jsonObject.has("IncludeTxPowerLevel")) {
+            builder.setIncludeTxPowerLevel(jsonObject.getBoolean("IncludeTxPowerLevel"));
+        }
+        if (jsonObject.has("ServiceData")) {
+            JSONArray serviceData = jsonObject.getJSONArray("ServiceData");
+            for (int i = 0; i < serviceData.length(); i++) {
+                JSONObject dataSet = serviceData.getJSONObject(i);
+                ParcelUuid parcelUuid = ParcelUuid.fromString(dataSet.getString("UUID"));
+                builder.addServiceUuid(parcelUuid);
+                if (dataSet.has("Data")) {
+                    byte[] data = Base64.decode(dataSet.getString("Data"), Base64.DEFAULT);
+                    builder.addServiceData(parcelUuid, data);
+                }
+            }
+        }
+        if (jsonObject.has("ManufacturerData")) {
+            JSONObject manufacturerData = jsonObject.getJSONObject("ManufacturerData");
+            int manufacturerId = manufacturerData.getInt("ManufacturerId");
+            byte[] manufacturerSpecificData =
+                    Base64.decode(jsonObject.getString("ManufacturerSpecificData"), Base64.DEFAULT);
+            builder.addManufacturerData(manufacturerId, manufacturerSpecificData);
+        }
+        return builder.build();
+    }
 }
diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonSerializer.java b/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonSerializer.java
index bd00f45..c555b92 100644
--- a/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonSerializer.java
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonSerializer.java
@@ -16,12 +16,16 @@
 
 package com.google.android.mobly.snippet.bundled.utils;
 
+import android.annotation.TargetApi;
 import android.bluetooth.BluetoothDevice;
+import android.bluetooth.le.AdvertiseSettings;
+import android.bluetooth.le.ScanRecord;
 import android.net.DhcpInfo;
 import android.net.wifi.SupplicantState;
 import android.net.wifi.WifiConfiguration;
 import android.net.wifi.WifiInfo;
 import android.os.Build;
+import android.os.Bundle;
 import android.os.ParcelUuid;
 import com.google.gson.Gson;
 import com.google.gson.GsonBuilder;
@@ -65,9 +69,7 @@ public class JsonSerializer {
     }
 
     public JSONObject toJson(Object object) throws JSONException {
-        if (object instanceof BluetoothDevice) {
-            return serializeBluetoothDevice((BluetoothDevice) object);
-        } else if (object instanceof DhcpInfo) {
+        if (object instanceof DhcpInfo) {
             return serializeDhcpInfo((DhcpInfo) object);
         } else if (object instanceof WifiConfiguration) {
             return serializeWifiConfiguration((WifiConfiguration) object);
@@ -109,13 +111,13 @@ public class JsonSerializer {
     private JSONObject serializeWifiConfiguration(WifiConfiguration data) throws JSONException {
         JSONObject result = new JSONObject(mGson.toJson(data));
         result.put("Status", WifiConfiguration.Status.strings[data.status]);
-        guaranteedPut(result, "SSID", trimQuotationMarks(data.SSID));
+        result.put("SSID", trimQuotationMarks(data.SSID));
         return result;
     }
 
     private JSONObject serializeWifiInfo(WifiInfo data) throws JSONException {
         JSONObject result = new JSONObject(mGson.toJson(data));
-        guaranteedPut(result, "SSID", trimQuotationMarks(data.getSSID()));
+        result.put("SSID", trimQuotationMarks(data.getSSID()));
         for (SupplicantState state : SupplicantState.values()) {
             if (data.getSupplicantState().equals(state)) {
                 result.put("SupplicantState", state.name());
@@ -124,71 +126,71 @@ public class JsonSerializer {
         return result;
     }
 
-    private JSONObject serializeBluetoothDevice(BluetoothDevice data) throws JSONException {
-        JSONObject result = new JSONObject();
-        guaranteedPut(result, "Address", data.getAddress());
-        final String bondStateFieldName = "BondState";
-        switch (data.getBondState()) {
-            case BluetoothDevice.BOND_NONE:
-                result.put(bondStateFieldName, "BOND_NONE");
-                break;
-            case BluetoothDevice.BOND_BONDING:
-                result.put(bondStateFieldName, "BOND_BONDING");
-                break;
-            case BluetoothDevice.BOND_BONDED:
-                result.put(bondStateFieldName, "BOND_BONDED");
-                break;
-        }
-        guaranteedPut(result, "Name", data.getName());
+    public Bundle serializeBluetoothDevice(BluetoothDevice data) {
+        Bundle result = new Bundle();
+        result.putString("Address", data.getAddress());
+        final String bondState =
+                MbsEnums.BLUETOOTH_DEVICE_BOND_STATE.getString(data.getBondState());
+        result.putString("BondState", bondState);
+        result.putString("Name", data.getName());
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
-            final String deviceTypeFieldName = "DeviceType";
-            switch (data.getType()) {
-                case BluetoothDevice.DEVICE_TYPE_CLASSIC:
-                    result.put(deviceTypeFieldName, "DEVICE_TYPE_CLASSIC");
-                    break;
-                case BluetoothDevice.DEVICE_TYPE_LE:
-                    result.put(deviceTypeFieldName, "DEVICE_TYPE_LE");
-                    break;
-                case BluetoothDevice.DEVICE_TYPE_DUAL:
-                    result.put(deviceTypeFieldName, "DEVICE_TYPE_DUAL");
-                    break;
-                case BluetoothDevice.DEVICE_TYPE_UNKNOWN:
-                    result.put(deviceTypeFieldName, "DEVICE_TYPE_UNKNOWN");
-                    break;
-            }
+            String deviceType = MbsEnums.BLUETOOTH_DEVICE_TYPE.getString(data.getType());
+            result.putString("DeviceType", deviceType);
             ParcelUuid[] parcelUuids = data.getUuids();
             if (parcelUuids != null) {
                 ArrayList<String> uuidStrings = new ArrayList<>(parcelUuids.length);
                 for (ParcelUuid parcelUuid : parcelUuids) {
                     uuidStrings.add(parcelUuid.getUuid().toString());
                 }
-                result.put("UUIDs", uuidStrings);
+                result.putStringArrayList("UUIDs", uuidStrings);
             }
         }
         return result;
     }
 
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    public Bundle serializeBleScanResult(android.bluetooth.le.ScanResult scanResult) {
+        Bundle result = new Bundle();
+        result.putBundle("Device", serializeBluetoothDevice(scanResult.getDevice()));
+        result.putInt("Rssi", scanResult.getRssi());
+        result.putBundle("ScanRecord", serializeBleScanRecord(scanResult.getScanRecord()));
+        result.putLong("TimestampNanos", scanResult.getTimestampNanos());
+        return result;
+    }
+
     /**
-     * Guarantees a field is put into a JSONObject even if it's null.
+     * Serialize ScanRecord for Bluetooth LE.
      *
-     * <p>By default, if the object of {@link JSONObject#put(String, Object)} is null, the `put`
-     * method would either remove the field or do nothing, causing serialized objects to have
-     * inconsistent fields.
+     * <p>Not all fields are serialized here. Will add more as we need.
      *
-     * <p>Use this method to put objects that may be null into the serialized JSONObject so the
-     * serialized objects have a consistent set of critical fields, like the SSID field in
-     * serialized WifiConfiguration objects.
+     * <pre>The returned {@link Bundle} has the following info:
+     *          "DeviceName", String
+     *          "TxPowerLevel", String
+     * </pre>
      *
-     * @param data
-     * @param name
-     * @param object
-     * @throws JSONException
+     * @param record A {@link ScanRecord} object.
+     * @return A {@link Bundle} object.
      */
-    private void guaranteedPut(JSONObject data, String name, Object object) throws JSONException {
-        if (object == null) {
-            data.put(name, JSONObject.NULL);
-        } else {
-            data.put(name, object);
-        }
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    private Bundle serializeBleScanRecord(ScanRecord record) {
+        Bundle result = new Bundle();
+        result.putString("DeviceName", record.getDeviceName());
+        result.putString(
+                "TxPowerLevel",
+                MbsEnums.BLE_ADVERTISE_TX_POWER.getString(record.getTxPowerLevel()));
+        return result;
+    }
+
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    public static Bundle serializeBleAdvertisingSettings(AdvertiseSettings advertiseSettings) {
+        Bundle result = new Bundle();
+        result.putString(
+                "TxPowerLevel",
+                MbsEnums.BLE_ADVERTISE_TX_POWER.getString(advertiseSettings.getTxPowerLevel()));
+        result.putString(
+                "Mode", MbsEnums.BLE_ADVERTISE_MODE.getString(advertiseSettings.getMode()));
+        result.putInt("Timeout", advertiseSettings.getTimeout());
+        result.putBoolean("IsConnectable", advertiseSettings.isConnectable());
+        return result;
     }
 }
diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/utils/MbsEnums.java b/src/main/java/com/google/android/mobly/snippet/bundled/utils/MbsEnums.java
new file mode 100644
index 0000000..33c425c
--- /dev/null
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/utils/MbsEnums.java
@@ -0,0 +1,91 @@
+package com.google.android.mobly.snippet.bundled.utils;
+
+import android.bluetooth.BluetoothDevice;
+import android.bluetooth.le.AdvertiseSettings;
+import android.bluetooth.le.ScanCallback;
+import android.bluetooth.le.ScanSettings;
+import android.os.Build;
+
+/** Mobly Bundled Snippets (MBS)'s {@link RpcEnum} objects representing enums in Android APIs. */
+public class MbsEnums {
+    static final RpcEnum BLE_ADVERTISE_MODE = buildBleAdvertiseModeEnum();
+    static final RpcEnum BLE_ADVERTISE_TX_POWER = buildBleAdvertiseTxPowerEnum();
+    public static final RpcEnum BLE_SCAN_FAILED_ERROR_CODE = buildBleScanFailedErrorCodeEnum();
+    public static final RpcEnum BLE_SCAN_RESULT_CALLBACK_TYPE =
+            buildBleScanResultCallbackTypeEnum();
+    static final RpcEnum BLUETOOTH_DEVICE_BOND_STATE = buildBluetoothDeviceBondState();
+    static final RpcEnum BLUETOOTH_DEVICE_TYPE = buildBluetoothDeviceTypeEnum();
+
+    private static RpcEnum buildBluetoothDeviceBondState() {
+        RpcEnum.Builder builder = new RpcEnum.Builder();
+        return builder.add("BOND_NONE", BluetoothDevice.BOND_NONE)
+                .add("BOND_BONDING", BluetoothDevice.BOND_BONDING)
+                .add("BOND_BONDED", BluetoothDevice.BOND_BONDED)
+                .build();
+    }
+
+    private static RpcEnum buildBluetoothDeviceTypeEnum() {
+        RpcEnum.Builder builder = new RpcEnum.Builder();
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR2) {
+            return builder.build();
+        }
+        return builder.add("DEVICE_TYPE_CLASSIC", BluetoothDevice.DEVICE_TYPE_CLASSIC)
+                .add("DEVICE_TYPE_LE", BluetoothDevice.DEVICE_TYPE_LE)
+                .add("DEVICE_TYPE_DUAL", BluetoothDevice.DEVICE_TYPE_DUAL)
+                .build();
+    }
+
+    private static RpcEnum buildBleAdvertiseTxPowerEnum() {
+        RpcEnum.Builder builder = new RpcEnum.Builder();
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            return builder.build();
+        }
+        return builder.add(
+                        "ADVERTISE_TX_POWER_ULTRA_LOW",
+                        AdvertiseSettings.ADVERTISE_TX_POWER_ULTRA_LOW)
+                .add("ADVERTISE_TX_POWER_LOW", AdvertiseSettings.ADVERTISE_TX_POWER_LOW)
+                .add("ADVERTISE_TX_POWER_MEDIUM", AdvertiseSettings.ADVERTISE_TX_POWER_MEDIUM)
+                .add("ADVERTISE_TX_POWER_HIGH", AdvertiseSettings.ADVERTISE_TX_POWER_HIGH)
+                .build();
+    }
+
+    private static RpcEnum buildBleAdvertiseModeEnum() {
+        RpcEnum.Builder builder = new RpcEnum.Builder();
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            return builder.build();
+        }
+        return builder.add("ADVERTISE_MODE_BALANCED", AdvertiseSettings.ADVERTISE_MODE_BALANCED)
+                .add("ADVERTISE_MODE_LOW_LATENCY", AdvertiseSettings.ADVERTISE_MODE_LOW_LATENCY)
+                .add("ADVERTISE_MODE_LOW_POWER", AdvertiseSettings.ADVERTISE_MODE_LOW_POWER)
+                .build();
+    }
+
+    private static RpcEnum buildBleScanFailedErrorCodeEnum() {
+        RpcEnum.Builder builder = new RpcEnum.Builder();
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            return builder.build();
+        }
+        return builder.add("SCAN_FAILED_ALREADY_STARTED", ScanCallback.SCAN_FAILED_ALREADY_STARTED)
+                .add(
+                        "SCAN_FAILED_APPLICATION_REGISTRATION_FAILED",
+                        ScanCallback.SCAN_FAILED_APPLICATION_REGISTRATION_FAILED)
+                .add(
+                        "SCAN_FAILED_FEATURE_UNSUPPORTED",
+                        ScanCallback.SCAN_FAILED_FEATURE_UNSUPPORTED)
+                .add("SCAN_FAILED_INTERNAL_ERROR", ScanCallback.SCAN_FAILED_INTERNAL_ERROR)
+                .build();
+    }
+
+    private static RpcEnum buildBleScanResultCallbackTypeEnum() {
+        RpcEnum.Builder builder = new RpcEnum.Builder();
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            return builder.build();
+        }
+        builder.add("CALLBACK_TYPE_ALL_MATCHES", ScanSettings.CALLBACK_TYPE_ALL_MATCHES);
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+            builder.add("CALLBACK_TYPE_FIRST_MATCH", ScanSettings.CALLBACK_TYPE_FIRST_MATCH);
+            builder.add("CALLBACK_TYPE_MATCH_LOST", ScanSettings.CALLBACK_TYPE_MATCH_LOST);
+        }
+        return builder.build();
+    }
+}
diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/utils/RpcEnum.java b/src/main/java/com/google/android/mobly/snippet/bundled/utils/RpcEnum.java
new file mode 100644
index 0000000..d3d95ae
--- /dev/null
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/utils/RpcEnum.java
@@ -0,0 +1,89 @@
+/*
+ * Copyright (C) 2017 Google 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 com.google.android.mobly.snippet.bundled.utils;
+
+import com.google.common.collect.ImmutableBiMap;
+
+/**
+ * A container type for handling String-Integer enum conversion in Rpc protocol.
+ *
+ * <p>In Serializing/Deserializing Android API enums, we often need to convert an enum value from
+ * one form to another. This container class makes it easier to do so.
+ *
+ * <p>Once built, an RpcEnum object is immutable.
+ */
+public class RpcEnum {
+    private final ImmutableBiMap<String, Integer> mEnums;
+
+    private RpcEnum(ImmutableBiMap.Builder<String, Integer> builder, int minSdk) {
+        mEnums = builder.build();
+    }
+
+    /**
+     * Get the int value of an enum based on its String value.
+     *
+     * @param enumString
+     * @return
+     */
+    public int getInt(String enumString) {
+        Integer result = mEnums.get(enumString);
+        if (result == null) {
+            throw new NoSuchFieldError("No int value found for: " + enumString);
+        }
+        return result;
+    }
+
+    /**
+     * Get the String value of an enum based on its int value.
+     *
+     * @param enumInt
+     * @return
+     */
+    public String getString(int enumInt) {
+        String result = mEnums.inverse().get(enumInt);
+        if (result == null) {
+            throw new NoSuchFieldError("No String value found for: " + enumInt);
+        }
+        return result;
+    }
+
+    /** Builder for RpcEnum. */
+    public static class Builder {
+        private final ImmutableBiMap.Builder<String, Integer> builder;
+        public int minSdk = 0;
+
+        public Builder() {
+            builder = new ImmutableBiMap.Builder<>();
+        }
+
+        /**
+         * Add an enum String-Integer pair.
+         *
+         * @param enumString
+         * @param enumInt
+         * @return
+         */
+        public Builder add(String enumString, int enumInt) {
+            builder.put(enumString, enumInt);
+            return this;
+        }
+
+        public RpcEnum build() {
+            return new RpcEnum(builder, minSdk);
+        }
+    }
+}
diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/utils/Utils.java b/src/main/java/com/google/android/mobly/snippet/bundled/utils/Utils.java
index 8736d85..8f4f7d6 100644
--- a/src/main/java/com/google/android/mobly/snippet/bundled/utils/Utils.java
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/utils/Utils.java
@@ -22,6 +22,7 @@ import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 
 public final class Utils {
+
     private Utils() {}
 
     /**