Initial Jack import.

Change-Id: I953cf0a520195a7187d791b2885848ad0d5a9b43

1 files changed, 188 insertions, 0 deletions

diff --git a/guava/src/com/google/common/util/concurrent/AbstractExecutionThreadService.java b/guava/src/com/google/common/util/concurrent/AbstractExecutionThreadService.java
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+++ b/guava/src/com/google/common/util/concurrent/AbstractExecutionThreadService.java
@@ -0,0 +1,188 @@
+/*
+ * Copyright (C) 2009 The Guava Authors
+ *
+ * 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.common.util.concurrent;
+
+import com.google.common.annotations.Beta;
+import com.google.common.base.Throwables;
+
+import java.util.concurrent.Executor;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * Base class for services that can implement {@link #startUp}, {@link #run} and
+ * {@link #shutDown} methods. This class uses a single thread to execute the
+ * service; consider {@link AbstractService} if you would like to manage any
+ * threading manually.
+ *
+ * @author Jesse Wilson
+ * @since 1.0
+ */
+@Beta
+public abstract class AbstractExecutionThreadService implements Service {
+  private static final Logger logger = Logger.getLogger(
+      AbstractExecutionThreadService.class.getName());
+
+  /* use AbstractService for state management */
+  private final Service delegate = new AbstractService() {
+    @Override protected final void doStart() {
+      executor().execute(new Runnable() {
+        @Override
+        public void run() {
+          try {
+            startUp();
+            notifyStarted();
+
+            if (isRunning()) {
+              try {
+                AbstractExecutionThreadService.this.run();
+              } catch (Throwable t) {
+                try {
+                  shutDown();
+                } catch (Exception ignored) {
+                  logger.log(Level.WARNING,
+                      "Error while attempting to shut down the service"
+                      + " after failure.", ignored);
+                }
+                throw t;
+              }
+            }
+
+            shutDown();
+            notifyStopped();
+          } catch (Throwable t) {
+            notifyFailed(t);
+            throw Throwables.propagate(t);
+          }
+        }
+      });
+    }
+
+    @Override protected void doStop() {
+      triggerShutdown();
+    }
+  };
+
+  /**
+   * Constructor for use by subclasses.
+   */
+  protected AbstractExecutionThreadService() {}
+
+  /**
+   * Start the service. This method is invoked on the execution thread.
+   *
+   * <p>By default this method does nothing.
+   */
+  protected void startUp() throws Exception {}
+
+  /**
+   * Run the service. This method is invoked on the execution thread.
+   * Implementations must respond to stop requests. You could poll for lifecycle
+   * changes in a work loop:
+   * <pre>
+   *   public void run() {
+   *     while ({@link #isRunning()}) {
+   *       // perform a unit of work
+   *     }
+   *   }
+   * </pre>
+   * ...or you could respond to stop requests by implementing {@link
+   * #triggerShutdown()}, which should cause {@link #run()} to return.
+   */
+  protected abstract void run() throws Exception;
+
+  /**
+   * Stop the service. This method is invoked on the execution thread.
+   *
+   * <p>By default this method does nothing.
+   */
+  // TODO: consider supporting a TearDownTestCase-like API
+  protected void shutDown() throws Exception {}
+
+  /**
+   * Invoked to request the service to stop.
+   *
+   * <p>By default this method does nothing.
+   */
+  protected void triggerShutdown() {}
+
+  /**
+   * Returns the {@link Executor} that will be used to run this service.
+   * Subclasses may override this method to use a custom {@link Executor}, which
+   * may configure its worker thread with a specific name, thread group or
+   * priority. The returned executor's {@link Executor#execute(Runnable)
+   * execute()} method is called when this service is started, and should return
+   * promptly.
+   *
+   * <p>The default implementation returns a new {@link Executor} that sets the
+   * name of its threads to the string returned by {@link #getServiceName}
+   */
+  protected Executor executor() {
+    return new Executor() {
+      @Override
+      public void execute(Runnable command) {
+        new Thread(command, getServiceName()).start();
+      }
+    };
+  }
+
+  @Override public String toString() {
+    return getServiceName() + " [" + state() + "]";
+  }
+
+  // We override instead of using ForwardingService so that these can be final.
+
+  @Override public final ListenableFuture<State> start() {
+    return delegate.start();
+  }
+
+  @Override public final State startAndWait() {
+    return delegate.startAndWait();
+  }
+
+  @Override public final boolean isRunning() {
+    return delegate.isRunning();
+  }
+
+  @Override public final State state() {
+    return delegate.state();
+  }
+
+  @Override public final ListenableFuture<State> stop() {
+    return delegate.stop();
+  }
+
+  @Override public final State stopAndWait() {
+    return delegate.stopAndWait();
+  }
+
+  @Override public final void addListener(Listener listener, Executor executor) {
+    delegate.addListener(listener, executor);
+  }
+
+  /**
+   * Returns the name of this service. {@link AbstractExecutionThreadService}
+   * may include the name in debugging output.
+   *
+   * <p>Subclasses may override this method.
+   *
+   * @since 10.0
+   */
+  protected String getServiceName() {
+    return getClass().getSimpleName();
+  }
+}