Utilities, conventions, serialize/deserialize mechanism, and basic Wi-Fi APIs

* Add basic Wi-Fi API support.
* Make bluetooth snippet style consistent with Wi-Fi.
* Add the mechanism to serialize and deserialize data types.
* Create a util for waiting on asynch operations.
* Enable Java8 for the project.
* Add formatter for the project.

Fixes #1.

5 files changed, 462 insertions, 25 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 a830ad9..79268da 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
@@ -19,13 +19,14 @@ package com.google.android.mobly.snippet.bundled;
 import android.bluetooth.BluetoothAdapter;
 import android.content.Context;
 import android.support.test.InstrumentationRegistry;
-
 import com.google.android.mobly.snippet.Snippet;
+import com.google.android.mobly.snippet.bundled.utils.Utils;
 import com.google.android.mobly.snippet.rpc.Rpc;
 
+/** Snippet class exposing Android APIs in BluetoothAdapter. */
 public class BluetoothAdapterSnippet implements Snippet {
-    private static class BluetoothException extends Exception {
-        public BluetoothException(String msg) {
+    private static class BluetoothAdapterSnippetException extends Exception {
+        public BluetoothAdapterSnippetException(String msg) {
             super(msg);
         }
     }
@@ -38,37 +39,26 @@ public class BluetoothAdapterSnippet implements Snippet {
         mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
     }
 
-    @Rpc(description = "Enable bluetooth")
-    public void bluetoothEnable() throws BluetoothException, InterruptedException {
+    @Rpc(description = "Enable bluetooth with a 30s timeout.")
+    public void bluetoothEnable() throws BluetoothAdapterSnippetException, InterruptedException {
         if (!mBluetoothAdapter.enable()) {
-            throw new BluetoothException("Failed to start enabling bluetooth");
-        }
-        int timeout = 30;
-        while (!mBluetoothAdapter.isEnabled() && timeout >= 0) {
-            Thread.sleep(1000);
-            timeout -= 1;
+            throw new BluetoothAdapterSnippetException("Failed to start enabling bluetooth");
         }
-        if (!mBluetoothAdapter.isEnabled()) {
-            throw new BluetoothException("Bluetooth did not turn on before timeout");
+        if (!Utils.waitUntil(() -> mBluetoothAdapter.isEnabled(), 30)) {
+            throw new BluetoothAdapterSnippetException("Bluetooth did not turn on within 30s.");
         }
     }
 
-    @Rpc(description = "Disable bluetooth")
-    public void bluetoothDisable() throws BluetoothException, InterruptedException {
+    @Rpc(description = "Disable bluetooth with a 30s timeout.")
+    public void bluetoothDisable() throws BluetoothAdapterSnippetException, InterruptedException {
         if (!mBluetoothAdapter.disable()) {
-            throw new BluetoothException("Failed to start disabling bluetooth");
+            throw new BluetoothAdapterSnippetException("Failed to start disabling bluetooth");
         }
-        int timeout = 30;
-        while (mBluetoothAdapter.isEnabled() && timeout >= 0) {
-            Thread.sleep(1000);
-            timeout -= 1;
-        }
-        if (mBluetoothAdapter.isEnabled()) {
-            throw new BluetoothException("Bluetooth did not turn off before timeout");
+        if (!Utils.waitUntil(() -> !mBluetoothAdapter.isEnabled(), 30)) {
+            throw new BluetoothAdapterSnippetException("Bluetooth did not turn off within 30s.");
         }
     }
 
     @Override
-    public void shutdown() {
-    }
+    public void shutdown() {}
 }
diff --git a/src/main/java/com/google/android/mobly/snippet/bundled/WifiManagerSnippet.java b/src/main/java/com/google/android/mobly/snippet/bundled/WifiManagerSnippet.java
new file mode 100644
index 0000000..1dca048
--- /dev/null
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/WifiManagerSnippet.java
@@ -0,0 +1,230 @@
+/*
+ * 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.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.net.wifi.ScanResult;
+import android.net.wifi.WifiConfiguration;
+import android.net.wifi.WifiManager;
+import android.support.annotation.Nullable;
+import android.support.test.InstrumentationRegistry;
+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.Utils;
+import com.google.android.mobly.snippet.rpc.Rpc;
+import com.google.android.mobly.snippet.util.Log;
+import java.util.ArrayList;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+/** Snippet class exposing Android APIs in WifiManager. */
+public class WifiManagerSnippet implements Snippet {
+    private static class WifiManagerSnippetException extends Exception {
+        public WifiManagerSnippetException(String msg) {
+            super(msg);
+        }
+    }
+
+    private final WifiManager mWifiManager;
+    private final Context mContext;
+    private static final String TAG = "WifiManagerSnippet";
+    private final JsonSerializer mJsonSerializer = new JsonSerializer();
+    private volatile boolean mIsScanning = false;
+    private volatile boolean mIsScanResultAvailable = false;
+
+    public WifiManagerSnippet() {
+        mContext = InstrumentationRegistry.getContext();
+        mWifiManager = (WifiManager) mContext.getSystemService(Context.WIFI_SERVICE);
+    }
+
+    @Rpc(description = "Turns on Wi-Fi with a 30s timeout.")
+    public void wifiEnable() throws InterruptedException, WifiManagerSnippetException {
+        if (!mWifiManager.setWifiEnabled(true)) {
+            throw new WifiManagerSnippetException("Failed to initiate enabling Wi-Fi.");
+        }
+        if (!Utils.waitUntil(
+                () -> mWifiManager.getWifiState() == WifiManager.WIFI_STATE_ENABLED, 30)) {
+            throw new WifiManagerSnippetException("Failed to enable Wi-Fi after 30s, timeout!");
+        }
+    }
+
+    @Rpc(description = "Turns off Wi-Fi with a 30s timeout.")
+    public void wifiDisable() throws InterruptedException, WifiManagerSnippetException {
+        if (!mWifiManager.setWifiEnabled(false)) {
+            throw new WifiManagerSnippetException("Failed to initiate disabling Wi-Fi.");
+        }
+        if (!Utils.waitUntil(
+                () -> mWifiManager.getWifiState() == WifiManager.WIFI_STATE_DISABLED, 30)) {
+            throw new WifiManagerSnippetException("Failed to disable Wi-Fi after 30s, timeout!");
+        }
+    }
+
+    @Rpc(description = "Trigger Wi-Fi scan.")
+    public void wifiStartScan() throws WifiManagerSnippetException {
+        if (!mWifiManager.startScan()) {
+            throw new WifiManagerSnippetException("Failed to initiate Wi-Fi scan.");
+        }
+    }
+
+    @Rpc(
+        description =
+                "Get Wi-Fi scan results, which is a list of serialized WifiScanResult objects."
+    )
+    public JSONArray wifiGetCachedScanResults() throws JSONException {
+        JSONArray results = new JSONArray();
+        for (ScanResult result : mWifiManager.getScanResults()) {
+            results.put(mJsonSerializer.toJson(result));
+        }
+        return results;
+    }
+
+    @Rpc(
+        description =
+                "Start scan, wait for scan to complete, and return results, which is a list of "
+                        + "serialized WifiScanResult objects."
+    )
+    public JSONArray wifiScanAndGetResults()
+            throws InterruptedException, JSONException, WifiManagerSnippetException {
+        mContext.registerReceiver(
+                new WifiScanReceiver(),
+                new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
+        wifiStartScan();
+        mIsScanResultAvailable = false;
+        mIsScanning = true;
+        if (!Utils.waitUntil(() -> mIsScanResultAvailable, 2 * 60)) {
+            throw new WifiManagerSnippetException(
+                    "Failed to get scan results after 2min, timeout!");
+        }
+        return wifiGetCachedScanResults();
+    }
+
+    @Rpc(
+        description =
+                "Connects to a Wi-Fi network. This covers the common network types like open and "
+                        + "WPA2."
+    )
+    public void wifiConnectSimple(String ssid, @Nullable String password)
+            throws InterruptedException, JSONException, WifiManagerSnippetException {
+        JSONObject config = new JSONObject();
+        config.put("SSID", ssid);
+        if (password != null) {
+            config.put("password", password);
+        }
+        wifiConnect(config);
+    }
+
+    /**
+     * Connect to a Wi-Fi network.
+     *
+     * @param wifiNetworkConfig A JSON object that contains the info required to connect to a Wi-Fi
+     *     network. It follows the fields of WifiConfiguration type, e.g. {"SSID": "myWifi",
+     *     "password": "12345678"}.
+     * @throws InterruptedException
+     * @throws JSONException
+     * @throws WifiManagerSnippetException
+     */
+    @Rpc(description = "Connects to a Wi-Fi network.")
+    public void wifiConnect(JSONObject wifiNetworkConfig)
+            throws InterruptedException, JSONException, WifiManagerSnippetException {
+        Log.d("Got network config: " + wifiNetworkConfig);
+        WifiConfiguration wifiConfig = JsonDeserializer.jsonToWifiConfig(wifiNetworkConfig);
+        int networkId = mWifiManager.addNetwork(wifiConfig);
+        mWifiManager.disconnect();
+        if (!mWifiManager.enableNetwork(networkId, true)) {
+            throw new WifiManagerSnippetException(
+                    "Failed to enable Wi-Fi network of ID: " + networkId);
+        }
+        if (!mWifiManager.reconnect()) {
+            throw new WifiManagerSnippetException(
+                    "Failed to reconnect to Wi-Fi network of ID: " + networkId);
+        }
+        if (!Utils.waitUntil(
+                () -> mWifiManager.getConnectionInfo().getSSID().equals(wifiConfig.SSID), 90)) {
+            throw new WifiManagerSnippetException(
+                    "Failed to connect to Wi-Fi network "
+                            + wifiNetworkConfig.toString()
+                            + ", timeout!");
+        }
+        Log.d(
+                "Connected to network '"
+                        + mWifiManager.getConnectionInfo().getSSID()
+                        + "' with ID "
+                        + mWifiManager.getConnectionInfo().getNetworkId());
+    }
+
+    @Rpc(
+        description =
+                "Forget a configured Wi-Fi network by its network ID, which is part of the"
+                        + " WifiConfiguration."
+    )
+    public void wifiRemoveNetwork(Integer networkId) throws WifiManagerSnippetException {
+        if (!mWifiManager.removeNetwork(networkId)) {
+            throw new WifiManagerSnippetException("Failed to remove network of ID: " + networkId);
+        }
+    }
+
+    @Rpc(
+        description =
+                "Get the list of configured Wi-Fi networks, each is a serialized "
+                        + "WifiConfiguration object."
+    )
+    public ArrayList<JSONObject> wifiGetConfiguredNetworks() throws JSONException {
+        ArrayList<JSONObject> networks = new ArrayList<>();
+        for (WifiConfiguration config : mWifiManager.getConfiguredNetworks()) {
+            networks.add(mJsonSerializer.toJson(config));
+        }
+        return networks;
+    }
+
+    @Rpc(
+        description =
+                "Get the information about the active Wi-Fi connection, which is a serialized "
+                        + "WifiInfo object."
+    )
+    public JSONObject wifiGetConnectionInfo() throws JSONException {
+        return mJsonSerializer.toJson(mWifiManager.getConnectionInfo());
+    }
+
+    @Rpc(
+        description =
+                "Get the info from last successful DHCP request, which is a serialized DhcpInfo "
+                        + "object."
+    )
+    public JSONObject wifiGetDhcpInfo() throws JSONException {
+        return mJsonSerializer.toJson(mWifiManager.getDhcpInfo());
+    }
+
+    @Override
+    public void shutdown() {}
+
+    private class WifiScanReceiver extends BroadcastReceiver {
+
+        @Override
+        public void onReceive(Context c, Intent intent) {
+            String action = intent.getAction();
+            if (action.equals(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)) {
+                mIsScanning = false;
+                mIsScanResultAvailable = true;
+            }
+        }
+    }
+}
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
new file mode 100644
index 0000000..4fc6b82
--- /dev/null
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonDeserializer.java
@@ -0,0 +1,43 @@
+/*
+ * 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 android.net.wifi.WifiConfiguration;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+/**
+ * A collection of methods used to deserialize JSON strings into data objects defined in Android
+ * API.
+ */
+public class JsonDeserializer {
+
+    private JsonDeserializer() {}
+
+    public static WifiConfiguration jsonToWifiConfig(JSONObject jsonObject) throws JSONException {
+        WifiConfiguration config = new WifiConfiguration();
+        config.SSID = "\"" + jsonObject.getString("SSID") + "\"";
+        config.hiddenSSID = jsonObject.optBoolean("hiddenSSID", false);
+        if (jsonObject.has("password")) {
+            config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);
+            config.preSharedKey = "\"" + jsonObject.getString("password") + "\"";
+        } else {
+            config.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
+        }
+        return config;
+    }
+}
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
new file mode 100644
index 0000000..58f8bac
--- /dev/null
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/utils/JsonSerializer.java
@@ -0,0 +1,120 @@
+/*
+ * 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 android.net.DhcpInfo;
+import android.net.wifi.SupplicantState;
+import android.net.wifi.WifiConfiguration;
+import android.net.wifi.WifiInfo;
+import com.google.gson.Gson;
+import com.google.gson.GsonBuilder;
+import java.lang.reflect.Modifier;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+/**
+ * A collection of methods used to serialize data types defined in Android API into JSON strings.
+ */
+public class JsonSerializer {
+    private static Gson mGson;
+
+    public JsonSerializer() {
+        GsonBuilder builder = new GsonBuilder();
+        mGson =
+                builder.serializeNulls()
+                        .excludeFieldsWithModifiers(Modifier.STATIC)
+                        .enableComplexMapKeySerialization()
+                        .disableInnerClassSerialization()
+                        .create();
+    }
+
+    /**
+     * Remove the extra quotation marks from the beginning and the end of a string.
+     *
+     * <p>This is useful for strings like the SSID field of Android's Wi-Fi configuration.
+     *
+     * @param originalString
+     */
+    private String trimQuotationMarks(String originalString) {
+        String result = originalString;
+        if (originalString.charAt(0) == '"'
+                && originalString.charAt(originalString.length() - 1) == '"') {
+            result = originalString.substring(1, originalString.length() - 1);
+        }
+        return result;
+    }
+
+    public JSONObject toJson(Object object) throws JSONException {
+        if (object instanceof DhcpInfo) {
+            return serializeDhcpInfo((DhcpInfo) object);
+        } else if (object instanceof WifiConfiguration) {
+            return serializeWifiConfiguration((WifiConfiguration) object);
+        } else if (object instanceof WifiInfo) {
+            return serializeWifiInfo((WifiInfo) object);
+        }
+        return defaultSerialization(object);
+    }
+
+    /**
+     * By default, we rely on Gson to do the right job.
+     *
+     * @param data An object to serialize
+     * @return A JSONObject that has the info of the serialized data object.
+     * @throws JSONException
+     */
+    private JSONObject defaultSerialization(Object data) throws JSONException {
+        return new JSONObject(mGson.toJson(data));
+    }
+
+    private JSONObject serializeDhcpInfo(DhcpInfo data) throws JSONException {
+        JSONObject result = new JSONObject(mGson.toJson(data));
+        int ipAddress = data.ipAddress;
+        byte[] addressBytes = {
+            (byte) (0xff & ipAddress),
+            (byte) (0xff & (ipAddress >> 8)),
+            (byte) (0xff & (ipAddress >> 16)),
+            (byte) (0xff & (ipAddress >> 24))
+        };
+        try {
+            String addressString = InetAddress.getByAddress(addressBytes).toString();
+            result.put("IpAddress", addressString);
+        } catch (UnknownHostException e) {
+            result.put("IpAddress", ipAddress);
+        }
+        return result;
+    }
+
+    private JSONObject serializeWifiConfiguration(WifiConfiguration data) throws JSONException {
+        JSONObject result = new JSONObject(mGson.toJson(data));
+        result.put("Status", WifiConfiguration.Status.strings[data.status]);
+        result.put("SSID", trimQuotationMarks(data.SSID));
+        return result;
+    }
+
+    private JSONObject serializeWifiInfo(WifiInfo data) throws JSONException {
+        JSONObject result = new JSONObject(mGson.toJson(data));
+        result.put("SSID", trimQuotationMarks(data.getSSID()));
+        for (SupplicantState state : SupplicantState.values()) {
+            if (data.getSupplicantState().equals(state)) {
+                result.put("SupplicantState", state.name());
+            }
+        }
+        return result;
+    }
+}
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
new file mode 100644
index 0000000..00bfbd2
--- /dev/null
+++ b/src/main/java/com/google/android/mobly/snippet/bundled/utils/Utils.java
@@ -0,0 +1,54 @@
+/*
+ * 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;
+
+public final class Utils {
+    private Utils() {}
+
+    /**
+     * Waits util a condition is met.
+     *
+     * <p>This is often used to wait for asynchronous operations to finish and the system to reach a
+     * desired state.
+     *
+     * @param predicate A lambda function that specifies the condition to wait for. This function
+     *     should return true when the desired state has been reached.
+     * @param timeout The number of seconds to wait for before giving up.
+     * @return true if the operation finished before timeout, false otherwise.
+     * @throws InterruptedException
+     */
+    public static boolean waitUntil(Utils.Predicate predicate, int timeout)
+            throws InterruptedException {
+        timeout *= 10;
+        while (!predicate.waitCondition() && timeout >= 0) {
+            Thread.sleep(100);
+            timeout -= 1;
+        }
+        if (predicate.waitCondition()) {
+            return true;
+        }
+        return false;
+    }
+
+    /**
+     * A function interface that is used by lambda functions signaling an async operation is still
+     * going on.
+     */
+    public interface Predicate {
+        boolean waitCondition();
+    }
+}