remove Windows support, revert new guava to small version

java/src/game/future/ExecutionList.java

@@ -0,0 +1,170 @@
+/*
+ * Copyright (C) 2007 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 game.future;
+
+import java.util.concurrent.Executor;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * <p>A list of listeners, each with an associated {@code Executor}, that
+ * guarantees that every {@code Runnable} that is {@linkplain #add added} will
+ * be executed after {@link #execute()} is called. Any {@code Runnable} added
+ * after the call to {@code execute} is still guaranteed to execute. There is no
+ * guarantee, however, that listeners will be executed in the order that they
+ * are added.
+ *
+ * <p>Exceptions thrown by a listener will be propagated up to the executor.
+ * Any exception thrown during {@code Executor.execute} (e.g., a {@code
+ * RejectedExecutionException} or an exception thrown by {@linkplain
+ * MoreExecutors#sameThreadExecutor inline execution}) will be caught and
+ * logged.
+ *
+ * @author Nishant Thakkar
+ * @author Sven Mawson
+ * @since 1.0
+ */
+final class ExecutionList {
+  // Logger to log exceptions caught when running runnables.
+//  @VisibleForTesting
+  static final Logger log = Logger.getLogger(ExecutionList.class.getName());
+
+  /**
+   * The runnable, executor pairs to execute.  This acts as a stack threaded through the 
+   * {@link RunnableExecutorPair#next} field.
+   */
+//  @GuardedBy("this")
+  private RunnableExecutorPair runnables;
+//  @GuardedBy("this")
+  private boolean executed;
+
+  /** Creates a new, empty {@link ExecutionList}. */
+  public ExecutionList() {}
+
+  /**
+   * Adds the {@code Runnable} and accompanying {@code Executor} to the list of
+   * listeners to execute. If execution has already begun, the listener is
+   * executed immediately.
+   *
+   * <p>Note: For fast, lightweight listeners that would be safe to execute in
+   * any thread, consider {@link MoreExecutors#sameThreadExecutor}. For heavier
+   * listeners, {@code sameThreadExecutor()} carries some caveats: First, the
+   * thread that the listener runs in depends on whether the {@code
+   * ExecutionList} has been executed at the time it is added. In particular,
+   * listeners may run in the thread that calls {@code add}. Second, the thread
+   * that calls {@link #execute} may be an internal implementation thread, such
+   * as an RPC network thread, and {@code sameThreadExecutor()} listeners may
+   * run in this thread. Finally, during the execution of a {@code
+   * sameThreadExecutor} listener, all other registered but unexecuted
+   * listeners are prevented from running, even if those listeners are to run
+   * in other executors.
+   */
+  public void add(Runnable runnable, Executor executor) {
+    // Fail fast on a null.  We throw NPE here because the contract of
+    // Executor states that it throws NPE on null listener, so we propagate
+    // that contract up into the add method as well.
+
+    // Lock while we check state.  We must maintain the lock while adding the
+    // new pair so that another thread can't run the list out from under us.
+    // We only add to the list if we have not yet started execution.
+    synchronized (this) {
+      if (!executed) {
+        runnables = new RunnableExecutorPair(runnable, executor, runnables);
+        return;
+      }
+    }
+    // Execute the runnable immediately. Because of scheduling this may end up
+    // getting called before some of the previously added runnables, but we're
+    // OK with that.  If we want to change the contract to guarantee ordering
+    // among runnables we'd have to modify the logic here to allow it.
+    executeListener(runnable, executor);
+  }
+
+  /**
+   * Runs this execution list, executing all existing pairs in the order they
+   * were added. However, note that listeners added after this point may be
+   * executed before those previously added, and note that the execution order
+   * of all listeners is ultimately chosen by the implementations of the
+   * supplied executors.
+   *
+   * <p>This method is idempotent. Calling it several times in parallel is
+   * semantically equivalent to calling it exactly once.
+   *
+   * @since 10.0 (present in 1.0 as {@code run})
+   */
+  public void execute() {
+    // Lock while we update our state so the add method above will finish adding
+    // any listeners before we start to run them.
+    RunnableExecutorPair list;
+    synchronized (this) {
+      if (executed) {
+        return;
+      }
+      executed = true;
+      list = runnables;
+      runnables = null;  // allow GC to free listeners even if this stays around for a while.
+    }
+    // If we succeeded then list holds all the runnables we to execute.  The pairs in the stack are
+    // in the opposite order from how they were added so we need to reverse the list to fulfill our
+    // contract.
+    // This is somewhat annoying, but turns out to be very fast in practice.  Alternatively, we 
+    // could drop the contract on the method that enforces this queue like behavior since depending
+    // on it is likely to be a bug anyway.
+    
+    // N.B. All writes to the list and the next pointers must have happened before the above 
+    // synchronized block, so we can iterate the list without the lock held here.
+    RunnableExecutorPair reversedList = null;
+    while (list != null) {
+      RunnableExecutorPair tmp = list;
+      list = list.next;
+      tmp.next = reversedList;
+      reversedList = tmp;
+    }
+    while (reversedList != null) {
+      executeListener(reversedList.runnable, reversedList.executor);
+      reversedList = reversedList.next;
+    }
+  }
+
+  /**
+   * Submits the given runnable to the given {@link Executor} catching and logging all 
+   * {@linkplain RuntimeException runtime exceptions} thrown by the executor.
+   */
+  private static void executeListener(Runnable runnable, Executor executor) {
+    try {
+      executor.execute(runnable);
+    } catch (RuntimeException e) {
+      // Log it and keep going, bad runnable and/or executor.  Don't
+      // punish the other runnables if we're given a bad one.  We only
+      // catch RuntimeException because we want Errors to propagate up.
+      log.log(Level.SEVERE, "RuntimeException while executing runnable "
+          + runnable + " with executor " + executor, e);
+    }
+  }
+
+  private static final class RunnableExecutorPair {
+    final Runnable runnable;
+    final Executor executor;
+    RunnableExecutorPair next;
+
+    RunnableExecutorPair(Runnable runnable, Executor executor, RunnableExecutorPair next) {
+      this.runnable = runnable;
+      this.executor = executor;
+      this.next = next;
+    }
+  }
+}