Add a method for output streams cleanup (appium#909)

* Add a method for output streams cleanup * Make lint happy

Author: Mykola Mokhnach

src/main/java/io/appium/java_client/service/local/AppiumDriverLocalService.java

@@ -35,37 +35,32 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.ReentrantLock;
+import javax.annotation.Nullable;
 
 public final class AppiumDriverLocalService extends DriverService {
 
  private static final String URL_MASK = "http://%s:%d/wd/hub";
  private final File nodeJSExec;
- private final int nodeJSPort;
  private final ImmutableList<String> nodeJSArgs;
  private final ImmutableMap<String, String> nodeJSEnvironment;
- private final String ipAddress;
  private final long startupTimeout;
  private final TimeUnit timeUnit;
  private final ReentrantLock lock = new ReentrantLock(true); //uses "fair" thread ordering policy
  private final ListOutputStream stream = new ListOutputStream().add(System.out);
  private final URL url;
 
-
-
  private CommandLine process = null;
 
  AppiumDriverLocalService(String ipAddress, File nodeJSExec, int nodeJSPort,
  ImmutableList<String> nodeJSArgs, ImmutableMap<String, String> nodeJSEnvironment,
  long startupTimeout, TimeUnit timeUnit) throws IOException {
  super(nodeJSExec, nodeJSPort, nodeJSArgs, nodeJSEnvironment);
- this.ipAddress = ipAddress;
  this.nodeJSExec = nodeJSExec;
- this.nodeJSPort = nodeJSPort;
  this.nodeJSArgs = nodeJSArgs;
  this.nodeJSEnvironment = nodeJSEnvironment;
  this.startupTimeout = startupTimeout;
  this.timeUnit = timeUnit;
- this.url = new URL(String.format(URL_MASK, this.ipAddress, this.nodeJSPort));
+ this.url = new URL(String.format(URL_MASK, ipAddress, nodeJSPort));
  }
 
  public static AppiumDriverLocalService buildDefaultService() {
@@ -185,6 +180,7 @@ private void destroyProcess() {
  * @return String logs if the server has been run.
  * null is returned otherwise.
  */
+ @Nullable
  public String getStdOut() {
  if (process != null) {
  return process.getStdOut();
@@ -215,4 +211,12 @@ public void addOutPutStreams(List<OutputStream> outputStreams) {
  }
  }
 
+ /**
+ * Remove all existing server output streams.
+ *
+ * @return true if at least one output stream has been cleared
+ */
+ public boolean clearOutPutStreams() {
+ return stream.clear();
+ }
 }

src/main/java/io/appium/java_client/service/local/ListOutputStream.java

@@ -59,4 +59,17 @@ public void close() throws IOException {
  stream.close();
  }
  }
+
+ /**
+ * Clears all the existing output streams.
+ *
+ * @return true if at least one output stream has been cleared
+ */
+ public boolean clear() {
+ if (streams.isEmpty()) {
+ return false;
+ }
+ streams.clear();
+ return true;
+ }
 }