From 9efd3942ab21ea30cec5193de2c62ff350bcb540 Mon Sep 17 00:00:00 2001
From: Mykola Mokhnach <nick+1@wire.com>
Date: Mon, 2 Apr 2018 19:05:51 +0200
Subject: [PATCH 1/8] Add wrappers for Android logcat broadcaster

---
 build.gradle                                  |   1 +
 .../java_client/android/AndroidDriver.java    |   2 +-
 .../android/ListensToLogcatMessages.java      |  71 +++++++++++++
 .../service/local/AppiumServiceBuilder.java   |   2 +-
 .../java_client/ws/CanHandleMessages.java     |  49 +++++++++
 .../java_client/ws/MessagesHandler.java       |  28 +++++
 .../java_client/ws/StringMessagesHandler.java |  15 +++
 .../java_client/ws/StringWebSocketClient.java | 100 ++++++++++++++++++
 .../java_client/ws/WebSocketClient.java       |  37 +++++++
 .../android/AndroidLogcatListenerTest.java    |  59 +++++++++++
 10 files changed, 362 insertions(+), 2 deletions(-)
 create mode 100644 src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
 create mode 100644 src/main/java/io/appium/java_client/ws/CanHandleMessages.java
 create mode 100644 src/main/java/io/appium/java_client/ws/MessagesHandler.java
 create mode 100644 src/main/java/io/appium/java_client/ws/StringMessagesHandler.java
 create mode 100644 src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
 create mode 100644 src/main/java/io/appium/java_client/ws/WebSocketClient.java
 create mode 100644 src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java

diff --git a/build.gradle b/build.gradle
index b0e0637b2..49e364c52 100644
--- a/build.gradle
+++ b/build.gradle
@@ -68,6 +68,7 @@ dependencies {
         force = true
     }
     compile 'com.google.code.gson:gson:2.8.2'
+    compile 'javax.websocket:javax.websocket-api:1.1'
     compile 'org.apache.httpcomponents:httpclient:4.5.5'
     compile 'cglib:cglib:3.2.6'
     compile 'commons-validator:commons-validator:1.6'
diff --git a/src/main/java/io/appium/java_client/android/AndroidDriver.java b/src/main/java/io/appium/java_client/android/AndroidDriver.java
index 3af82826b..d3b37f19f 100644
--- a/src/main/java/io/appium/java_client/android/AndroidDriver.java
+++ b/src/main/java/io/appium/java_client/android/AndroidDriver.java
@@ -53,7 +53,7 @@ public class AndroidDriver<T extends WebElement>
         FindsByAndroidUIAutomator<T>, LocksDevice, HasAndroidSettings, HasDeviceDetails,
         HasSupportedPerformanceDataType, AuthenticatesByFinger,
         CanRecordScreen, SupportsSpecialEmulatorCommands,
-        SupportsNetworkStateManagement {
+        SupportsNetworkStateManagement, ListensToLogcatMessages {
 
     private static final String ANDROID_PLATFORM = MobilePlatform.ANDROID;
 
diff --git a/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java b/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
new file mode 100644
index 000000000..1027a05f2
--- /dev/null
+++ b/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
@@ -0,0 +1,71 @@
+package io.appium.java_client.android;
+
+import static io.appium.java_client.service.local.AppiumServiceBuilder.DEFAULT_APPIUM_PORT;
+import static org.openqa.selenium.remote.DriverCommand.EXECUTE_SCRIPT;
+
+import com.google.common.collect.ImmutableMap;
+
+import io.appium.java_client.ExecutesMethod;
+import io.appium.java_client.ws.StringMessagesHandler;
+import io.appium.java_client.ws.StringWebSocketClient;
+import org.openqa.selenium.remote.RemoteWebDriver;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+public interface ListensToLogcatMessages extends ExecutesMethod {
+    StringWebSocketClient logcatClient = new StringWebSocketClient();
+
+    /**
+     * Start logcat messages broadcast via web socket.
+     * This method assumes that Appium server is running on localhost and
+     * is assigned to the default port (4723).
+     */
+    default void startLogcatBroadcast() {
+        startLogcatBroadcast("localhost", DEFAULT_APPIUM_PORT);
+    }
+
+    /**
+     * Start logcat messages broadcast via web socket.
+     *
+     * @param host the name of the host where Appium server is running
+     * @param port the port of the host where Appium server is running
+     */
+    default void startLogcatBroadcast(String host, int port) {
+        execute(EXECUTE_SCRIPT, ImmutableMap.of("script", "mobile: startLogsBroadcast"));
+        final URI endpointUri;
+        try {
+            endpointUri = new URI(String.format("ws://%s:%s/ws/session/%s/appium/device/logcat",
+                    host, port, ((RemoteWebDriver) this).getSessionId()));
+        } catch (URISyntaxException e) {
+            throw new IllegalArgumentException(e);
+        }
+        logcatClient.connect(endpointUri);
+    }
+
+    /**
+     * Adds a new log broadcasting handler.
+     * Several handlers might be assigned to a single server.
+     * Multiple calls to this method will cause the handler
+     * to be called multiple times.
+     *
+     * @param handler an instance of a class, which implement string message handlers
+     */
+    default void addLogcatListener(StringMessagesHandler handler) {
+        logcatClient.addMessageHandler(handler);
+    }
+
+    /**
+     * Removes all existing logcat message handlers.
+     */
+    default void removeAllLogcatListeners() {
+        logcatClient.removeAllMessageHandlers();
+    }
+
+    /**
+     * Stops logcat messages broadcast via web socket.
+     */
+    default void stopLogcatBroadcast() {
+        execute(EXECUTE_SCRIPT, ImmutableMap.of("script", "mobile: stopLogsBroadcast"));
+    }
+}
diff --git a/src/main/java/io/appium/java_client/service/local/AppiumServiceBuilder.java b/src/main/java/io/appium/java_client/service/local/AppiumServiceBuilder.java
index 08522521c..c8b44414e 100644
--- a/src/main/java/io/appium/java_client/service/local/AppiumServiceBuilder.java
+++ b/src/main/java/io/appium/java_client/service/local/AppiumServiceBuilder.java
@@ -75,7 +75,7 @@ public final class AppiumServiceBuilder
         File.separator + BUILD_FOLDER
                 + File.separator + LIB_FOLDER
                 + File.separator + MAIN_JS;
-    private static final int DEFAULT_APPIUM_PORT = 4723;
+    public static final int DEFAULT_APPIUM_PORT = 4723;
     private static final String BASH = "bash";
     private static final String CMD_EXE = "cmd.exe";
     private static final String NODE = "node";
diff --git a/src/main/java/io/appium/java_client/ws/CanHandleMessages.java b/src/main/java/io/appium/java_client/ws/CanHandleMessages.java
new file mode 100644
index 000000000..209a79acd
--- /dev/null
+++ b/src/main/java/io/appium/java_client/ws/CanHandleMessages.java
@@ -0,0 +1,49 @@
+package io.appium.java_client.ws;
+
+import java.util.List;
+
+/**
+ * This interface might be assigned to classes, which
+ * are defined as web socket clients.
+ */
+public interface CanHandleMessages<T extends MessagesHandler> {
+    /**
+     * @return The list of web socket message handlers.
+     */
+    List<T> messageHandlers();
+
+    /**
+     * Register a new message handler.
+     *
+     * @param msgHandler an instance of a class, which
+     *                   implements MessagesHandler interface
+     */
+    default void addMessageHandler(T msgHandler) {
+        messageHandlers().add(msgHandler);
+    }
+
+    /**
+     * Removes an existing message handler.
+     *
+     * @param msgHandler an instance of a class, which
+     *                   implements MessagesHandler interface
+     * @return true if the given class instance was registered before and has been successfully removed.
+     */
+    default boolean removeMessageHandler(T msgHandler) {
+        return messageHandlers().remove(msgHandler);
+    }
+
+    /**
+     * @return The count of registered message handlers.
+     */
+    default int messageHandlersCount() {
+        return messageHandlers().size();
+    }
+
+    /**
+     * Removes all registered message handlers.
+     */
+    default void removeAllMessageHandlers() {
+        messageHandlers().clear();
+    }
+}
diff --git a/src/main/java/io/appium/java_client/ws/MessagesHandler.java b/src/main/java/io/appium/java_client/ws/MessagesHandler.java
new file mode 100644
index 000000000..02db8f314
--- /dev/null
+++ b/src/main/java/io/appium/java_client/ws/MessagesHandler.java
@@ -0,0 +1,28 @@
+package io.appium.java_client.ws;
+
+/**
+ * This is the basic interface for all web socket message handlers.
+ */
+public interface MessagesHandler {
+    /**
+     * This event is fired when the client is
+     * successfully connected to a web socket.
+     */
+    void onConnected();
+
+    /**
+     * This event is fired when the client is
+     * disconnected from a web socket.
+     */
+    void onDisconnected();
+
+    /**
+     * This event is fired when there is an error
+     * in the web socket connection.
+     * onDisconnected event is always generated after
+     * onError happens.
+     *
+     * @param reason the actual error reason.
+     */
+    void onError(Throwable reason);
+}
diff --git a/src/main/java/io/appium/java_client/ws/StringMessagesHandler.java b/src/main/java/io/appium/java_client/ws/StringMessagesHandler.java
new file mode 100644
index 000000000..211c24e57
--- /dev/null
+++ b/src/main/java/io/appium/java_client/ws/StringMessagesHandler.java
@@ -0,0 +1,15 @@
+package io.appium.java_client.ws;
+
+/**
+ * All classes, that handle web socket messages of String type
+ * must implement this interface.
+ */
+public interface StringMessagesHandler extends MessagesHandler {
+    /**
+     * This event is fired when the client receives
+     * a new string message from a web socket.
+     *
+     * @param message the actual message content
+     */
+    void onMessage(String message);
+}
diff --git a/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java b/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
new file mode 100644
index 000000000..1360b5c77
--- /dev/null
+++ b/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
@@ -0,0 +1,100 @@
+package io.appium.java_client.ws;
+
+import java.io.IOException;
+import java.net.URI;
+import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
+import javax.websocket.ClientEndpoint;
+import javax.websocket.CloseReason;
+import javax.websocket.EndpointConfig;
+import javax.websocket.OnClose;
+import javax.websocket.OnError;
+import javax.websocket.OnMessage;
+import javax.websocket.OnOpen;
+import javax.websocket.Session;
+
+@ClientEndpoint
+public class StringWebSocketClient extends WebSocketClient
+        implements CanHandleMessages<StringMessagesHandler> {
+    private final List<StringMessagesHandler> messageHandlers = new CopyOnWriteArrayList<>();
+    private volatile Session session;
+
+    @Override
+    public void connect(URI endpoint) {
+        if (session != null) {
+            if (endpoint.equals(this.getEndpoint())) {
+                return;
+            }
+            removeAllMessageHandlers();
+            try {
+                session.close();
+            } catch (IOException e) {
+                // ignore
+            }
+            session = null;
+        }
+        super.connect(endpoint);
+    }
+
+    /**
+     * This event if fired when the client is successfully
+     * connected to a web socket.
+     *
+     * @param session the actual web socket session instance
+     * @param config endpoint config
+     */
+    @OnOpen
+    public void onOpen(Session session, EndpointConfig config) {
+        this.session = session;
+        messageHandlers().forEach(MessagesHandler::onConnected);
+    }
+
+    /**
+     * This event if fired when the client is
+     * disconnected from a web socket.
+     *
+     * @param session the actual web socket session instance
+     * @param reason connection close reason
+     */
+    @OnClose
+    public void onClose(Session session, CloseReason reason) {
+        this.session = null;
+        messageHandlers().forEach(MessagesHandler::onDisconnected);
+    }
+
+    /**
+     * This event if fired when there is an unexpected
+     * error in web socket connection.
+     *
+     * @param session the actual web socket session instance
+     * @param reason the actual error reason
+     */
+    @OnError
+    public void onError(Session session, Throwable reason) {
+        this.session = null;
+        messageHandlers().forEach(x -> {
+            x.onError(reason);
+            x.onDisconnected();
+        });
+        throw new RuntimeException(reason);
+    }
+
+    /**
+     * This event if fired when there is a
+     * new message from the web socket.
+     *
+     * @param message the actual message content.
+     */
+    @OnMessage
+    public void onMessage(String message) {
+        messageHandlers().forEach(x -> x.onMessage(message));
+    }
+
+    /**
+     * @return The list of all registered web socket messages handlers.
+     */
+    @Override
+    public List<StringMessagesHandler> messageHandlers() {
+        return messageHandlers;
+    }
+}
diff --git a/src/main/java/io/appium/java_client/ws/WebSocketClient.java b/src/main/java/io/appium/java_client/ws/WebSocketClient.java
new file mode 100644
index 000000000..a61c102c8
--- /dev/null
+++ b/src/main/java/io/appium/java_client/ws/WebSocketClient.java
@@ -0,0 +1,37 @@
+package io.appium.java_client.ws;
+
+import org.openqa.selenium.WebDriverException;
+
+import java.io.IOException;
+import java.net.URI;
+import javax.websocket.ContainerProvider;
+import javax.websocket.DeploymentException;
+
+public abstract class WebSocketClient {
+    private URI endpoint;
+
+    private void setEndpoint(URI endpoint) {
+        this.endpoint = endpoint;
+    }
+
+    public URI getEndpoint() {
+        return this.endpoint;
+    }
+
+    /**
+     * Connects web socket client.
+     *
+     * @param endpoint The full address of an endpoint to connect to.
+     *                 Usually starts with 'ws://'.
+     */
+    public void connect(URI endpoint) {
+        try {
+            ContainerProvider
+                    .getWebSocketContainer()
+                    .connectToServer(this, endpoint);
+            setEndpoint(endpoint);
+        } catch (IOException | DeploymentException e) {
+            throw new WebDriverException(e);
+        }
+    }
+}
diff --git a/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java b/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
new file mode 100644
index 000000000..8b8af281f
--- /dev/null
+++ b/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
@@ -0,0 +1,59 @@
+package io.appium.java_client.android;
+
+import static org.junit.Assert.assertTrue;
+
+import io.appium.java_client.ws.StringMessagesHandler;
+import org.junit.Test;
+
+import java.time.Duration;
+import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
+
+public class AndroidLogcatListenerTest extends BaseAndroidTest {
+
+    @Test
+    public void verifyLogcatListenerCanBeAssigned() {
+        final Semaphore messageSemaphore = new Semaphore(1);
+        final Semaphore connectedSemaphore = new Semaphore(1);
+        final Duration timeout = Duration.ofSeconds(5);
+
+        try {
+            driver.startLogcatBroadcast();
+            driver.addLogcatListener(new StringMessagesHandler() {
+                @Override
+                public void onMessage(String message) {
+                    messageSemaphore.release();
+                }
+
+                @Override
+                public void onConnected() {
+                    connectedSemaphore.release();
+                }
+
+                @Override
+                public void onDisconnected() {
+                    // ignore
+                }
+
+                @Override
+                public void onError(Throwable reason) {
+                    // ignore
+                }
+            });
+
+            connectedSemaphore.acquire();
+            messageSemaphore.acquire();
+
+            assertTrue(String.format("Didn't connect to the web socket after %s timeout", timeout),
+                    connectedSemaphore.tryAcquire(timeout.toMillis(), TimeUnit.MILLISECONDS));
+            assertTrue(String.format("Didn't receive any log message after %s timeout", timeout),
+                    messageSemaphore.tryAcquire(timeout.toMillis(), TimeUnit.MILLISECONDS));
+        } catch (InterruptedException e) {
+            throw new RuntimeException(e);
+        } finally {
+            connectedSemaphore.release();
+            messageSemaphore.release();
+            driver.stopLogcatBroadcast();
+        }
+    }
+}

From 91aa380117aada6a87663e9bab8c4dfcce463204 Mon Sep 17 00:00:00 2001
From: Mykola Mokhnach <nick+1@wire.com>
Date: Tue, 3 Apr 2018 09:27:32 +0200
Subject: [PATCH 2/8] Address PR comments

---
 .../android/ListensToLogcatMessages.java      | 14 +++++++++--
 .../java_client/ws/CanHandleMessages.java     | 10 ++++----
 .../java_client/ws/MessagesHandler.java       | 16 ++++++++----
 .../java_client/ws/StringMessagesHandler.java | 15 -----------
 .../java_client/ws/StringWebSocketClient.java | 25 +++++++++----------
 .../android/AndroidLogcatListenerTest.java    |  8 +++---
 6 files changed, 44 insertions(+), 44 deletions(-)
 delete mode 100644 src/main/java/io/appium/java_client/ws/StringMessagesHandler.java

diff --git a/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java b/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
index 1027a05f2..fe01e8f27 100644
--- a/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
+++ b/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
@@ -6,7 +6,7 @@
 import com.google.common.collect.ImmutableMap;
 
 import io.appium.java_client.ExecutesMethod;
-import io.appium.java_client.ws.StringMessagesHandler;
+import io.appium.java_client.ws.MessagesHandler;
 import io.appium.java_client.ws.StringWebSocketClient;
 import org.openqa.selenium.remote.RemoteWebDriver;
 
@@ -25,6 +25,16 @@ default void startLogcatBroadcast() {
         startLogcatBroadcast("localhost", DEFAULT_APPIUM_PORT);
     }
 
+    /**
+     * Start logcat messages broadcast via web socket.
+     * This method assumes that Appium server is assigned to the default port (4723).
+     *
+     * @param host the name of the host where Appium server is running
+     */
+    default void startLogcatBroadcast(String host) {
+        startLogcatBroadcast(host, DEFAULT_APPIUM_PORT);
+    }
+
     /**
      * Start logcat messages broadcast via web socket.
      *
@@ -51,7 +61,7 @@ default void startLogcatBroadcast(String host, int port) {
      *
      * @param handler an instance of a class, which implement string message handlers
      */
-    default void addLogcatListener(StringMessagesHandler handler) {
+    default void addLogcatListener(MessagesHandler<String> handler) {
         logcatClient.addMessageHandler(handler);
     }
 
diff --git a/src/main/java/io/appium/java_client/ws/CanHandleMessages.java b/src/main/java/io/appium/java_client/ws/CanHandleMessages.java
index 209a79acd..8751c493d 100644
--- a/src/main/java/io/appium/java_client/ws/CanHandleMessages.java
+++ b/src/main/java/io/appium/java_client/ws/CanHandleMessages.java
@@ -10,7 +10,7 @@ public interface CanHandleMessages<T extends MessagesHandler> {
     /**
      * @return The list of web socket message handlers.
      */
-    List<T> messageHandlers();
+    List<T> getMessageHandlers();
 
     /**
      * Register a new message handler.
@@ -19,7 +19,7 @@ public interface CanHandleMessages<T extends MessagesHandler> {
      *                   implements MessagesHandler interface
      */
     default void addMessageHandler(T msgHandler) {
-        messageHandlers().add(msgHandler);
+        getMessageHandlers().add(msgHandler);
     }
 
     /**
@@ -30,20 +30,20 @@ default void addMessageHandler(T msgHandler) {
      * @return true if the given class instance was registered before and has been successfully removed.
      */
     default boolean removeMessageHandler(T msgHandler) {
-        return messageHandlers().remove(msgHandler);
+        return getMessageHandlers().remove(msgHandler);
     }
 
     /**
      * @return The count of registered message handlers.
      */
     default int messageHandlersCount() {
-        return messageHandlers().size();
+        return getMessageHandlers().size();
     }
 
     /**
      * Removes all registered message handlers.
      */
     default void removeAllMessageHandlers() {
-        messageHandlers().clear();
+        getMessageHandlers().clear();
     }
 }
diff --git a/src/main/java/io/appium/java_client/ws/MessagesHandler.java b/src/main/java/io/appium/java_client/ws/MessagesHandler.java
index 02db8f314..940b5793e 100644
--- a/src/main/java/io/appium/java_client/ws/MessagesHandler.java
+++ b/src/main/java/io/appium/java_client/ws/MessagesHandler.java
@@ -3,7 +3,7 @@
 /**
  * This is the basic interface for all web socket message handlers.
  */
-public interface MessagesHandler {
+public interface MessagesHandler<T> {
     /**
      * This event is fired when the client is
      * successfully connected to a web socket.
@@ -19,10 +19,16 @@ public interface MessagesHandler {
     /**
      * This event is fired when there is an error
      * in the web socket connection.
-     * onDisconnected event is always generated after
-     * onError happens.
      *
-     * @param reason the actual error reason.
+     * @param cause the actual error reason.
      */
-    void onError(Throwable reason);
+    void onError(Throwable cause);
+
+    /**
+     * This event is fired when the client receives
+     * a new message from a web socket.
+     *
+     * @param message the actual web socket message content
+     */
+    void onMessage(T message);
 }
diff --git a/src/main/java/io/appium/java_client/ws/StringMessagesHandler.java b/src/main/java/io/appium/java_client/ws/StringMessagesHandler.java
deleted file mode 100644
index 211c24e57..000000000
--- a/src/main/java/io/appium/java_client/ws/StringMessagesHandler.java
+++ /dev/null
@@ -1,15 +0,0 @@
-package io.appium.java_client.ws;
-
-/**
- * All classes, that handle web socket messages of String type
- * must implement this interface.
- */
-public interface StringMessagesHandler extends MessagesHandler {
-    /**
-     * This event is fired when the client receives
-     * a new string message from a web socket.
-     *
-     * @param message the actual message content
-     */
-    void onMessage(String message);
-}
diff --git a/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java b/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
index 1360b5c77..f56b7cf9a 100644
--- a/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
+++ b/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
@@ -1,5 +1,7 @@
 package io.appium.java_client.ws;
 
+import org.openqa.selenium.WebDriverException;
+
 import java.io.IOException;
 import java.net.URI;
 import java.util.List;
@@ -15,8 +17,8 @@
 
 @ClientEndpoint
 public class StringWebSocketClient extends WebSocketClient
-        implements CanHandleMessages<StringMessagesHandler> {
-    private final List<StringMessagesHandler> messageHandlers = new CopyOnWriteArrayList<>();
+        implements CanHandleMessages<MessagesHandler<String>> {
+    private final List<MessagesHandler<String>> messageHandlers = new CopyOnWriteArrayList<>();
     private volatile Session session;
 
     @Override
@@ -46,7 +48,7 @@ public void connect(URI endpoint) {
     @OnOpen
     public void onOpen(Session session, EndpointConfig config) {
         this.session = session;
-        messageHandlers().forEach(MessagesHandler::onConnected);
+        getMessageHandlers().forEach(MessagesHandler::onConnected);
     }
 
     /**
@@ -59,7 +61,7 @@ public void onOpen(Session session, EndpointConfig config) {
     @OnClose
     public void onClose(Session session, CloseReason reason) {
         this.session = null;
-        messageHandlers().forEach(MessagesHandler::onDisconnected);
+        getMessageHandlers().forEach(MessagesHandler::onDisconnected);
     }
 
     /**
@@ -67,16 +69,13 @@ public void onClose(Session session, CloseReason reason) {
      * error in web socket connection.
      *
      * @param session the actual web socket session instance
-     * @param reason the actual error reason
+     * @param cause the actual error reason
      */
     @OnError
-    public void onError(Session session, Throwable reason) {
+    public void onError(Session session, Throwable cause) {
         this.session = null;
-        messageHandlers().forEach(x -> {
-            x.onError(reason);
-            x.onDisconnected();
-        });
-        throw new RuntimeException(reason);
+        getMessageHandlers().forEach(x -> x.onError(cause));
+        throw new WebDriverException(cause);
     }
 
     /**
@@ -87,14 +86,14 @@ public void onError(Session session, Throwable reason) {
      */
     @OnMessage
     public void onMessage(String message) {
-        messageHandlers().forEach(x -> x.onMessage(message));
+        getMessageHandlers().forEach(x -> x.onMessage(message));
     }
 
     /**
      * @return The list of all registered web socket messages handlers.
      */
     @Override
-    public List<StringMessagesHandler> messageHandlers() {
+    public List<MessagesHandler<String>> getMessageHandlers() {
         return messageHandlers;
     }
 }
diff --git a/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java b/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
index 8b8af281f..571b50ec5 100644
--- a/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
+++ b/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
@@ -2,7 +2,7 @@
 
 import static org.junit.Assert.assertTrue;
 
-import io.appium.java_client.ws.StringMessagesHandler;
+import io.appium.java_client.ws.MessagesHandler;
 import org.junit.Test;
 
 import java.time.Duration;
@@ -19,7 +19,7 @@ public void verifyLogcatListenerCanBeAssigned() {
 
         try {
             driver.startLogcatBroadcast();
-            driver.addLogcatListener(new StringMessagesHandler() {
+            driver.addLogcatListener(new MessagesHandler<String>() {
                 @Override
                 public void onMessage(String message) {
                     messageSemaphore.release();
@@ -36,7 +36,7 @@ public void onDisconnected() {
                 }
 
                 @Override
-                public void onError(Throwable reason) {
+                public void onError(Throwable cause) {
                     // ignore
                 }
             });
@@ -49,7 +49,7 @@ public void onError(Throwable reason) {
             assertTrue(String.format("Didn't receive any log message after %s timeout", timeout),
                     messageSemaphore.tryAcquire(timeout.toMillis(), TimeUnit.MILLISECONDS));
         } catch (InterruptedException e) {
-            throw new RuntimeException(e);
+            throw new IllegalStateException(e);
         } finally {
             connectedSemaphore.release();
             messageSemaphore.release();

From 443e29a5c9fee2bab214d924d9e1d327a4017023 Mon Sep 17 00:00:00 2001
From: Mykola Mokhnach <nick+1@wire.com>
Date: Tue, 3 Apr 2018 10:34:50 +0200
Subject: [PATCH 3/8] Remove unused arguments

---
 .../java_client/ws/StringWebSocketClient.java      | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java b/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
index f56b7cf9a..ec30a3c44 100644
--- a/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
+++ b/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
@@ -7,8 +7,6 @@
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
 import javax.websocket.ClientEndpoint;
-import javax.websocket.CloseReason;
-import javax.websocket.EndpointConfig;
 import javax.websocket.OnClose;
 import javax.websocket.OnError;
 import javax.websocket.OnMessage;
@@ -27,6 +25,7 @@ public void connect(URI endpoint) {
             if (endpoint.equals(this.getEndpoint())) {
                 return;
             }
+
             removeAllMessageHandlers();
             try {
                 session.close();
@@ -43,10 +42,9 @@ public void connect(URI endpoint) {
      * connected to a web socket.
      *
      * @param session the actual web socket session instance
-     * @param config endpoint config
      */
     @OnOpen
-    public void onOpen(Session session, EndpointConfig config) {
+    public void onOpen(Session session) {
         this.session = session;
         getMessageHandlers().forEach(MessagesHandler::onConnected);
     }
@@ -54,12 +52,9 @@ public void onOpen(Session session, EndpointConfig config) {
     /**
      * This event if fired when the client is
      * disconnected from a web socket.
-     *
-     * @param session the actual web socket session instance
-     * @param reason connection close reason
      */
     @OnClose
-    public void onClose(Session session, CloseReason reason) {
+    public void onClose() {
         this.session = null;
         getMessageHandlers().forEach(MessagesHandler::onDisconnected);
     }
@@ -68,11 +63,10 @@ public void onClose(Session session, CloseReason reason) {
      * This event if fired when there is an unexpected
      * error in web socket connection.
      *
-     * @param session the actual web socket session instance
      * @param cause the actual error reason
      */
     @OnError
-    public void onError(Session session, Throwable cause) {
+    public void onError(Throwable cause) {
         this.session = null;
         getMessageHandlers().forEach(x -> x.onError(cause));
         throw new WebDriverException(cause);

From c76ffc5bca0cb6b17a26a946c09e4833044c21a6 Mon Sep 17 00:00:00 2001
From: Mykola Mokhnach <nick+1@wire.com>
Date: Fri, 6 Apr 2018 14:28:57 +0200
Subject: [PATCH 4/8] Tune execute args

---
 .../java_client/android/ListensToLogcatMessages.java       | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java b/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
index fe01e8f27..c39f35ef6 100644
--- a/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
+++ b/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
@@ -12,6 +12,7 @@
 
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.util.Collections;
 
 public interface ListensToLogcatMessages extends ExecutesMethod {
     StringWebSocketClient logcatClient = new StringWebSocketClient();
@@ -42,7 +43,8 @@ default void startLogcatBroadcast(String host) {
      * @param port the port of the host where Appium server is running
      */
     default void startLogcatBroadcast(String host, int port) {
-        execute(EXECUTE_SCRIPT, ImmutableMap.of("script", "mobile: startLogsBroadcast"));
+        execute(EXECUTE_SCRIPT, ImmutableMap.of("script", "mobile: startLogsBroadcast",
+                "args", Collections.emptyList()));
         final URI endpointUri;
         try {
             endpointUri = new URI(String.format("ws://%s:%s/ws/session/%s/appium/device/logcat",
@@ -76,6 +78,7 @@ default void removeAllLogcatListeners() {
      * Stops logcat messages broadcast via web socket.
      */
     default void stopLogcatBroadcast() {
-        execute(EXECUTE_SCRIPT, ImmutableMap.of("script", "mobile: stopLogsBroadcast"));
+        execute(EXECUTE_SCRIPT, ImmutableMap.of("script", "mobile: stopLogsBroadcast",
+                "args", Collections.emptyList()));
     }
 }

From cbf4c43ccc683842dfc32414a8ce5cc16ff2fd36 Mon Sep 17 00:00:00 2001
From: Mykola Mokhnach <nick+1@wire.com>
Date: Fri, 6 Apr 2018 15:48:00 +0200
Subject: [PATCH 5/8] Add missing dependencies

---
 build.gradle                                  |  6 ++-
 .../android/AndroidLogcatListenerTest.java    | 49 ++++++++-----------
 2 files changed, 25 insertions(+), 30 deletions(-)

diff --git a/build.gradle b/build.gradle
index 49e364c52..9aff9e21d 100644
--- a/build.gradle
+++ b/build.gradle
@@ -68,7 +68,6 @@ dependencies {
         force = true
     }
     compile 'com.google.code.gson:gson:2.8.2'
-    compile 'javax.websocket:javax.websocket-api:1.1'
     compile 'org.apache.httpcomponents:httpclient:4.5.5'
     compile 'cglib:cglib:3.2.6'
     compile 'commons-validator:commons-validator:1.6'
@@ -77,7 +76,10 @@ dependencies {
     compile 'org.springframework:spring-context:5.0.3.RELEASE'
     compile 'org.aspectj:aspectjweaver:1.8.13'
     compile 'org.openpnp:opencv:3.2.0-1'
-
+    compile 'javax.websocket:javax.websocket-api:1.1'
+    compile 'org.glassfish.tyrus:tyrus-client:1.1'
+    compile 'org.glassfish.tyrus:tyrus-container-grizzly:1.1'
+    
     testCompile 'junit:junit:4.12'
     testCompile 'org.hamcrest:hamcrest-all:1.3'
 }
diff --git a/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java b/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
index 571b50ec5..d66ed81d8 100644
--- a/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
+++ b/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
@@ -14,44 +14,37 @@ public class AndroidLogcatListenerTest extends BaseAndroidTest {
     @Test
     public void verifyLogcatListenerCanBeAssigned() {
         final Semaphore messageSemaphore = new Semaphore(1);
-        final Semaphore connectedSemaphore = new Semaphore(1);
         final Duration timeout = Duration.ofSeconds(5);
 
+        driver.addLogcatListener(new MessagesHandler<String>() {
+            @Override
+            public void onMessage(String message) {
+                messageSemaphore.release();
+            }
+
+            @Override
+            public void onConnected() {
+                System.out.println("Connected to web socket");
+            }
+
+            @Override
+            public void onDisconnected() {
+                System.out.println("Disconnected from web socket");
+            }
+
+            @Override
+            public void onError(Throwable cause) {
+                cause.printStackTrace();
+            }
+        });
         try {
             driver.startLogcatBroadcast();
-            driver.addLogcatListener(new MessagesHandler<String>() {
-                @Override
-                public void onMessage(String message) {
-                    messageSemaphore.release();
-                }
-
-                @Override
-                public void onConnected() {
-                    connectedSemaphore.release();
-                }
-
-                @Override
-                public void onDisconnected() {
-                    // ignore
-                }
-
-                @Override
-                public void onError(Throwable cause) {
-                    // ignore
-                }
-            });
-
-            connectedSemaphore.acquire();
             messageSemaphore.acquire();
-
-            assertTrue(String.format("Didn't connect to the web socket after %s timeout", timeout),
-                    connectedSemaphore.tryAcquire(timeout.toMillis(), TimeUnit.MILLISECONDS));
             assertTrue(String.format("Didn't receive any log message after %s timeout", timeout),
                     messageSemaphore.tryAcquire(timeout.toMillis(), TimeUnit.MILLISECONDS));
         } catch (InterruptedException e) {
             throw new IllegalStateException(e);
         } finally {
-            connectedSemaphore.release();
             messageSemaphore.release();
             driver.stopLogcatBroadcast();
         }

From c978b1bbeff65ff51dd57b7cca2f252569304040 Mon Sep 17 00:00:00 2001
From: Mykola Mokhnach <nick+1@wire.com>
Date: Fri, 6 Apr 2018 15:54:25 +0200
Subject: [PATCH 6/8] Add license headers

---
 .../android/ListensToLogcatMessages.java         | 16 ++++++++++++++++
 .../appium/java_client/ws/CanHandleMessages.java | 16 ++++++++++++++++
 .../appium/java_client/ws/MessagesHandler.java   | 16 ++++++++++++++++
 .../java_client/ws/StringWebSocketClient.java    | 16 ++++++++++++++++
 .../appium/java_client/ws/WebSocketClient.java   | 16 ++++++++++++++++
 5 files changed, 80 insertions(+)

diff --git a/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java b/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
index c39f35ef6..1a98abe49 100644
--- a/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
+++ b/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
@@ -1,3 +1,19 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ * 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 io.appium.java_client.android;
 
 import static io.appium.java_client.service.local.AppiumServiceBuilder.DEFAULT_APPIUM_PORT;
diff --git a/src/main/java/io/appium/java_client/ws/CanHandleMessages.java b/src/main/java/io/appium/java_client/ws/CanHandleMessages.java
index 8751c493d..daff2f7d6 100644
--- a/src/main/java/io/appium/java_client/ws/CanHandleMessages.java
+++ b/src/main/java/io/appium/java_client/ws/CanHandleMessages.java
@@ -1,3 +1,19 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ * 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 io.appium.java_client.ws;
 
 import java.util.List;
diff --git a/src/main/java/io/appium/java_client/ws/MessagesHandler.java b/src/main/java/io/appium/java_client/ws/MessagesHandler.java
index 940b5793e..9665932f7 100644
--- a/src/main/java/io/appium/java_client/ws/MessagesHandler.java
+++ b/src/main/java/io/appium/java_client/ws/MessagesHandler.java
@@ -1,3 +1,19 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ * 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 io.appium.java_client.ws;
 
 /**
diff --git a/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java b/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
index ec30a3c44..46e3535fd 100644
--- a/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
+++ b/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
@@ -1,3 +1,19 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ * 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 io.appium.java_client.ws;
 
 import org.openqa.selenium.WebDriverException;
diff --git a/src/main/java/io/appium/java_client/ws/WebSocketClient.java b/src/main/java/io/appium/java_client/ws/WebSocketClient.java
index a61c102c8..0101e5d2f 100644
--- a/src/main/java/io/appium/java_client/ws/WebSocketClient.java
+++ b/src/main/java/io/appium/java_client/ws/WebSocketClient.java
@@ -1,3 +1,19 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ * 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 io.appium.java_client.ws;
 
 import org.openqa.selenium.WebDriverException;

From 67c4235d90fd8597d7a6f506b77cce7ffe0f7e85 Mon Sep 17 00:00:00 2001
From: Mykola Mokhnach <nick+1@wire.com>
Date: Thu, 12 Apr 2018 16:27:38 +0200
Subject: [PATCH 7/8] Rewrite the stuff using functional approach

---
 .../android/ListensToLogcatMessages.java      | 52 ++++++++++++++---
 ...gesHandler.java => CanHandleConnects.java} | 35 +++++-------
 .../java_client/ws/CanHandleDisconnects.java  | 43 ++++++++++++++
 .../java_client/ws/CanHandleErrors.java       | 44 ++++++++++++++
 .../java_client/ws/CanHandleMessages.java     | 39 +++----------
 .../java_client/ws/StringWebSocketClient.java | 57 ++++++++++++++++---
 .../android/AndroidLogcatListenerTest.java    | 26 ++-------
 7 files changed, 207 insertions(+), 89 deletions(-)
 rename src/main/java/io/appium/java_client/ws/{MessagesHandler.java => CanHandleConnects.java} (51%)
 create mode 100644 src/main/java/io/appium/java_client/ws/CanHandleDisconnects.java
 create mode 100644 src/main/java/io/appium/java_client/ws/CanHandleErrors.java

diff --git a/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java b/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
index 1a98abe49..4b2629815 100644
--- a/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
+++ b/src/main/java/io/appium/java_client/android/ListensToLogcatMessages.java
@@ -22,13 +22,13 @@
 import com.google.common.collect.ImmutableMap;
 
 import io.appium.java_client.ExecutesMethod;
-import io.appium.java_client.ws.MessagesHandler;
 import io.appium.java_client.ws.StringWebSocketClient;
 import org.openqa.selenium.remote.RemoteWebDriver;
 
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.Collections;
+import java.util.function.Consumer;
 
 public interface ListensToLogcatMessages extends ExecutesMethod {
     StringWebSocketClient logcatClient = new StringWebSocketClient();
@@ -72,22 +72,60 @@ default void startLogcatBroadcast(String host, int port) {
     }
 
     /**
-     * Adds a new log broadcasting handler.
+     * Adds a new log messages broadcasting handler.
      * Several handlers might be assigned to a single server.
-     * Multiple calls to this method will cause the handler
+     * Multiple calls to this method will cause such handler
      * to be called multiple times.
      *
-     * @param handler an instance of a class, which implement string message handlers
+     * @param handler a function, which accepts a single argument, which is the actual log message
      */
-    default void addLogcatListener(MessagesHandler<String> handler) {
+    default void addLogcatMessagesListener(Consumer<String> handler) {
         logcatClient.addMessageHandler(handler);
     }
 
     /**
-     * Removes all existing logcat message handlers.
+     * Adds a new log broadcasting errors handler.
+     * Several handlers might be assigned to a single server.
+     * Multiple calls to this method will cause such handler
+     * to be called multiple times.
+     *
+     * @param handler a function, which accepts a single argument, which is the actual exception instance
+     */
+    default void addLogcatErrorsListener(Consumer<Throwable> handler) {
+        logcatClient.addErrorHandler(handler);
+    }
+
+    /**
+     * Adds a new log broadcasting connection handler.
+     * Several handlers might be assigned to a single server.
+     * Multiple calls to this method will cause such handler
+     * to be called multiple times.
+     *
+     * @param handler a function, which is executed as soon as the client is successfully
+     *                connected to the web socket
+     */
+    default void addLogcatConnectionListener(Runnable handler) {
+        logcatClient.addConnectionHandler(handler);
+    }
+
+    /**
+     * Adds a new log broadcasting disconnection handler.
+     * Several handlers might be assigned to a single server.
+     * Multiple calls to this method will cause such handler
+     * to be called multiple times.
+     *
+     * @param handler a function, which is executed as soon as the client is successfully
+     *                disconnected from the web socket
+     */
+    default void addLogcatDisconnectionListener(Runnable handler) {
+        logcatClient.addDisconnectionHandler(handler);
+    }
+
+    /**
+     * Removes all existing logcat handlers.
      */
     default void removeAllLogcatListeners() {
-        logcatClient.removeAllMessageHandlers();
+        logcatClient.removeAllHandlers();
     }
 
     /**
diff --git a/src/main/java/io/appium/java_client/ws/MessagesHandler.java b/src/main/java/io/appium/java_client/ws/CanHandleConnects.java
similarity index 51%
rename from src/main/java/io/appium/java_client/ws/MessagesHandler.java
rename to src/main/java/io/appium/java_client/ws/CanHandleConnects.java
index 9665932f7..47cf91d09 100644
--- a/src/main/java/io/appium/java_client/ws/MessagesHandler.java
+++ b/src/main/java/io/appium/java_client/ws/CanHandleConnects.java
@@ -16,35 +16,28 @@
 
 package io.appium.java_client.ws;
 
-/**
- * This is the basic interface for all web socket message handlers.
- */
-public interface MessagesHandler<T> {
-    /**
-     * This event is fired when the client is
-     * successfully connected to a web socket.
-     */
-    void onConnected();
+import java.util.List;
+
+public interface CanHandleConnects {
 
     /**
-     * This event is fired when the client is
-     * disconnected from a web socket.
+     * @return The list of web socket connection handlers.
      */
-    void onDisconnected();
+    List<Runnable> getConnectionHandlers();
 
     /**
-     * This event is fired when there is an error
-     * in the web socket connection.
+     * Register a new message handler.
      *
-     * @param cause the actual error reason.
+     * @param handler a callback function, which is going to be executed when web socket connection event arrives
      */
-    void onError(Throwable cause);
+    default void addConnectionHandler(Runnable handler) {
+        getConnectionHandlers().add(handler);
+    }
 
     /**
-     * This event is fired when the client receives
-     * a new message from a web socket.
-     *
-     * @param message the actual web socket message content
+     * Removes existing web socket connection handlers.
      */
-    void onMessage(T message);
+    default void removeConnectionHandlers() {
+        getConnectionHandlers().clear();
+    }
 }
diff --git a/src/main/java/io/appium/java_client/ws/CanHandleDisconnects.java b/src/main/java/io/appium/java_client/ws/CanHandleDisconnects.java
new file mode 100644
index 000000000..52c429726
--- /dev/null
+++ b/src/main/java/io/appium/java_client/ws/CanHandleDisconnects.java
@@ -0,0 +1,43 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ * 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 io.appium.java_client.ws;
+
+import java.util.List;
+
+public interface CanHandleDisconnects {
+
+    /**
+     * @return The list of web socket disconnection handlers.
+     */
+    List<Runnable> getDisconnectionHandlers();
+
+    /**
+     * Register a new web socket disconnect handler.
+     *
+     * @param handler a callback function, which is going to be executed when web socket disconnect event arrives
+     */
+    default void addDisconnectionHandler(Runnable handler) {
+        getDisconnectionHandlers().add(handler);
+    }
+
+    /**
+     * Removes existing disconnection handlers.
+     */
+    default void removeDisconnectionHandlers() {
+        getDisconnectionHandlers().clear();
+    }
+}
diff --git a/src/main/java/io/appium/java_client/ws/CanHandleErrors.java b/src/main/java/io/appium/java_client/ws/CanHandleErrors.java
new file mode 100644
index 000000000..86f2b4e9e
--- /dev/null
+++ b/src/main/java/io/appium/java_client/ws/CanHandleErrors.java
@@ -0,0 +1,44 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ * 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 io.appium.java_client.ws;
+
+import java.util.List;
+import java.util.function.Consumer;
+
+public interface CanHandleErrors {
+
+    /**
+     * @return The list of web socket error handlers.
+     */
+    List<Consumer<Throwable>> getErrorHandlers();
+
+    /**
+     * Register a new error handler.
+     *
+     * @param handler a callback function, which accepts the received exception instance as a parameter
+     */
+    default void addErrorHandler(Consumer<Throwable> handler) {
+        getErrorHandlers().add(handler);
+    }
+
+    /**
+     * Removes existing error handlers.
+     */
+    default void removeErrorHandlers() {
+        getErrorHandlers().clear();
+    }
+}
diff --git a/src/main/java/io/appium/java_client/ws/CanHandleMessages.java b/src/main/java/io/appium/java_client/ws/CanHandleMessages.java
index daff2f7d6..f1688f3d3 100644
--- a/src/main/java/io/appium/java_client/ws/CanHandleMessages.java
+++ b/src/main/java/io/appium/java_client/ws/CanHandleMessages.java
@@ -17,49 +17,28 @@
 package io.appium.java_client.ws;
 
 import java.util.List;
+import java.util.function.Consumer;
 
-/**
- * This interface might be assigned to classes, which
- * are defined as web socket clients.
- */
-public interface CanHandleMessages<T extends MessagesHandler> {
+public interface CanHandleMessages<T> {
     /**
      * @return The list of web socket message handlers.
      */
-    List<T> getMessageHandlers();
+    List<Consumer<T>> getMessageHandlers();
 
     /**
      * Register a new message handler.
      *
-     * @param msgHandler an instance of a class, which
-     *                   implements MessagesHandler interface
-     */
-    default void addMessageHandler(T msgHandler) {
-        getMessageHandlers().add(msgHandler);
-    }
-
-    /**
-     * Removes an existing message handler.
-     *
-     * @param msgHandler an instance of a class, which
-     *                   implements MessagesHandler interface
-     * @return true if the given class instance was registered before and has been successfully removed.
+     * @param handler a callback function, which accepts the received message as a parameter
      */
-    default boolean removeMessageHandler(T msgHandler) {
-        return getMessageHandlers().remove(msgHandler);
+    default void addMessageHandler(Consumer<T> handler) {
+        getMessageHandlers().add(handler);
     }
 
     /**
-     * @return The count of registered message handlers.
+     * Removes existing message handlers.
      */
-    default int messageHandlersCount() {
-        return getMessageHandlers().size();
-    }
-
-    /**
-     * Removes all registered message handlers.
-     */
-    default void removeAllMessageHandlers() {
+    default void removeMessageHandlers() {
         getMessageHandlers().clear();
     }
 }
+
diff --git a/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java b/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
index 46e3535fd..ebb99d7da 100644
--- a/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
+++ b/src/main/java/io/appium/java_client/ws/StringWebSocketClient.java
@@ -22,6 +22,7 @@
 import java.net.URI;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.function.Consumer;
 import javax.websocket.ClientEndpoint;
 import javax.websocket.OnClose;
 import javax.websocket.OnError;
@@ -30,9 +31,13 @@
 import javax.websocket.Session;
 
 @ClientEndpoint
-public class StringWebSocketClient extends WebSocketClient
-        implements CanHandleMessages<MessagesHandler<String>> {
-    private final List<MessagesHandler<String>> messageHandlers = new CopyOnWriteArrayList<>();
+public class StringWebSocketClient extends WebSocketClient implements
+        CanHandleMessages<String>, CanHandleErrors, CanHandleConnects, CanHandleDisconnects {
+    private final List<Consumer<String>> messageHandlers = new CopyOnWriteArrayList<>();
+    private final List<Consumer<Throwable>> errorHandlers = new CopyOnWriteArrayList<>();
+    private final List<Runnable> connectHandlers = new CopyOnWriteArrayList<>();
+    private final List<Runnable> disconnectHandlers = new CopyOnWriteArrayList<>();
+
     private volatile Session session;
 
     @Override
@@ -42,7 +47,7 @@ public void connect(URI endpoint) {
                 return;
             }
 
-            removeAllMessageHandlers();
+            removeAllHandlers();
             try {
                 session.close();
             } catch (IOException e) {
@@ -62,7 +67,7 @@ public void connect(URI endpoint) {
     @OnOpen
     public void onOpen(Session session) {
         this.session = session;
-        getMessageHandlers().forEach(MessagesHandler::onConnected);
+        getConnectionHandlers().forEach(Runnable::run);
     }
 
     /**
@@ -72,7 +77,7 @@ public void onOpen(Session session) {
     @OnClose
     public void onClose() {
         this.session = null;
-        getMessageHandlers().forEach(MessagesHandler::onDisconnected);
+        getDisconnectionHandlers().forEach(Runnable::run);
     }
 
     /**
@@ -84,7 +89,7 @@ public void onClose() {
     @OnError
     public void onError(Throwable cause) {
         this.session = null;
-        getMessageHandlers().forEach(x -> x.onError(cause));
+        getErrorHandlers().forEach(x -> x.accept(cause));
         throw new WebDriverException(cause);
     }
 
@@ -96,14 +101,48 @@ public void onError(Throwable cause) {
      */
     @OnMessage
     public void onMessage(String message) {
-        getMessageHandlers().forEach(x -> x.onMessage(message));
+        getMessageHandlers().forEach(x -> x.accept(message));
     }
 
     /**
      * @return The list of all registered web socket messages handlers.
      */
     @Override
-    public List<MessagesHandler<String>> getMessageHandlers() {
+    public List<Consumer<String>> getMessageHandlers() {
         return messageHandlers;
     }
+
+    /**
+     * @return The list of all registered web socket error handlers.
+     */
+    @Override
+    public List<Consumer<Throwable>> getErrorHandlers() {
+        return errorHandlers;
+    }
+
+    /**
+     * @return The list of all registered web socket connection handlers.
+     */
+    @Override
+    public List<Runnable> getConnectionHandlers() {
+        return connectHandlers;
+    }
+
+    /**
+     * @return The list of all registered web socket disconnection handlers.
+     */
+    @Override
+    public List<Runnable> getDisconnectionHandlers() {
+        return disconnectHandlers;
+    }
+
+    /**
+     * Remove all the registered handlers.
+     */
+    public void removeAllHandlers() {
+        removeMessageHandlers();
+        removeErrorHandlers();
+        removeConnectionHandlers();
+        removeDisconnectionHandlers();
+    }
 }
diff --git a/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java b/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
index d66ed81d8..731fd352e 100644
--- a/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
+++ b/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
@@ -2,7 +2,6 @@
 
 import static org.junit.Assert.assertTrue;
 
-import io.appium.java_client.ws.MessagesHandler;
 import org.junit.Test;
 
 import java.time.Duration;
@@ -16,27 +15,10 @@ public void verifyLogcatListenerCanBeAssigned() {
         final Semaphore messageSemaphore = new Semaphore(1);
         final Duration timeout = Duration.ofSeconds(5);
 
-        driver.addLogcatListener(new MessagesHandler<String>() {
-            @Override
-            public void onMessage(String message) {
-                messageSemaphore.release();
-            }
-
-            @Override
-            public void onConnected() {
-                System.out.println("Connected to web socket");
-            }
-
-            @Override
-            public void onDisconnected() {
-                System.out.println("Disconnected from web socket");
-            }
-
-            @Override
-            public void onError(Throwable cause) {
-                cause.printStackTrace();
-            }
-        });
+        driver.addLogcatMessagesListener((msg) -> messageSemaphore.release());
+        driver.addLogcatConnectionListener(() -> System.out.println("Connected to the web socket"));
+        driver.addLogcatDisconnectionListener(() -> System.out.println("Disconnected from the web socket"));
+        driver.addLogcatErrorsListener(Throwable::printStackTrace);
         try {
             driver.startLogcatBroadcast();
             messageSemaphore.acquire();

From 74e7fdd9073a9813a1d9e07561b3c3d1855e7a37 Mon Sep 17 00:00:00 2001
From: Mykola Mokhnach <nick+1@wire.com>
Date: Fri, 13 Apr 2018 16:58:06 +0200
Subject: [PATCH 8/8] Minimize the app to push log messages

---
 .../java_client/android/AndroidLogcatListenerTest.java    | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java b/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
index 731fd352e..5cfdee5c2 100644
--- a/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
+++ b/src/test/java/io/appium/java_client/android/AndroidLogcatListenerTest.java
@@ -2,6 +2,7 @@
 
 import static org.junit.Assert.assertTrue;
 
+import org.apache.commons.lang3.time.DurationFormatUtils;
 import org.junit.Test;
 
 import java.time.Duration;
@@ -13,7 +14,7 @@ public class AndroidLogcatListenerTest extends BaseAndroidTest {
     @Test
     public void verifyLogcatListenerCanBeAssigned() {
         final Semaphore messageSemaphore = new Semaphore(1);
-        final Duration timeout = Duration.ofSeconds(5);
+        final Duration timeout = Duration.ofSeconds(15);
 
         driver.addLogcatMessagesListener((msg) -> messageSemaphore.release());
         driver.addLogcatConnectionListener(() -> System.out.println("Connected to the web socket"));
@@ -22,7 +23,10 @@ public void verifyLogcatListenerCanBeAssigned() {
         try {
             driver.startLogcatBroadcast();
             messageSemaphore.acquire();
-            assertTrue(String.format("Didn't receive any log message after %s timeout", timeout),
+            // This is needed for pushing some internal log messages
+            driver.runAppInBackground(Duration.ofSeconds(1));
+            assertTrue(String.format("Didn't receive any log message after %s timeout",
+                    DurationFormatUtils.formatDuration(timeout.toMillis(), "H:mm:ss", true)),
                     messageSemaphore.tryAcquire(timeout.toMillis(), TimeUnit.MILLISECONDS));
         } catch (InterruptedException e) {
             throw new IllegalStateException(e);