mv com/google/domain/registry google/registry

This change renames directories in preparation for the great package
rename. The repository is now in a broken state because the code
itself hasn't been updated. However this should ensure that git
correctly preserves history for each file.

java/google/registry/util/AppEngineTimeLimiter.java

@@ -0,0 +1,83 @@
+// Copyright 2016 The Domain Registry Authors. All Rights Reserved.
+//
+// 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.domain.registry.util;
+
+import static com.google.appengine.api.ThreadManager.currentRequestThreadFactory;
+
+import com.google.common.util.concurrent.SimpleTimeLimiter;
+import com.google.common.util.concurrent.TimeLimiter;
+
+import java.util.List;
+import java.util.concurrent.AbstractExecutorService;
+import java.util.concurrent.TimeUnit;
+
+
+/**
+ * A factory for {@link TimeLimiter} instances that use request threads, which carry the namespace
+ * and live only as long as the request that spawned them.
+ * <p>
+ * It is safe to reuse instances of this class, but there is no benefit in doing so over creating a
+ * fresh instance each time.
+ */
+public class AppEngineTimeLimiter {
+
+  /**
+   * An {@code ExecutorService} that uses a new thread for every task.
+   * <p>
+   * We need to use fresh threads for each request so that we can use App Engine's request threads.
+   * If we cached these threads in a thread pool (and if we were executing on a backend, where there
+   * is no time limit on requests) the caching would cause the thread to keep the task that opened
+   * it alive even after returning an http response, and would also cause the namespace that the
+   * original thread was created in to leak out to later reuses of the thread.
+   * <p>
+   * Since there are no cached resources, this class doesn't have to support being shutdown.
+   */
+  private static class NewRequestThreadExecutorService extends AbstractExecutorService {
+
+    @Override
+    public void execute(Runnable command) {
+      currentRequestThreadFactory().newThread(command).start();
+    }
+
+    @Override
+    public boolean isShutdown() {
+      return false;
+    }
+
+    @Override
+    public boolean isTerminated() {
+      return false;
+    }
+
+    @Override
+    public void shutdown() {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public List<Runnable> shutdownNow() {
+      throw new UnsupportedOperationException();
+    }
+
+    @Override
+    public boolean awaitTermination(long timeout, TimeUnit unit) {
+      throw new UnsupportedOperationException();
+    }
+  }
+
+  public static TimeLimiter create() {
+    return new SimpleTimeLimiter(new NewRequestThreadExecutorService());
+  }
+}