| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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 org.apache.hadoop.ipc; |
| |
| import java.io.IOException; |
| import java.security.PrivilegedExceptionAction; |
| import java.util.concurrent.ExecutionException; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| |
| import org.apache.hadoop.ipc.Server.Call; |
| import org.apache.hadoop.ipc.protobuf.RpcHeaderProtos.RpcResponseHeaderProto.RpcStatusProto; |
| import org.apache.hadoop.security.UserGroupInformation; |
| |
| public abstract class ExternalCall<T> extends Call { |
| private final PrivilegedExceptionAction<T> action; |
| private final AtomicBoolean done = new AtomicBoolean(); |
| private T result; |
| private Throwable error; |
| |
| public ExternalCall(PrivilegedExceptionAction<T> action) { |
| this.action = action; |
| } |
| |
| @Override |
| public String getDetailedMetricsName() { |
| return "(external)"; |
| } |
| |
| public abstract UserGroupInformation getRemoteUser(); |
| |
| public final T get() throws InterruptedException, ExecutionException { |
| waitForCompletion(); |
| if (error != null) { |
| throw new ExecutionException(error); |
| } |
| return result; |
| } |
| |
| // wait for response to be triggered to support postponed calls |
| private void waitForCompletion() throws InterruptedException { |
| synchronized(done) { |
| while (!done.get()) { |
| try { |
| done.wait(); |
| } catch (InterruptedException ie) { |
| if (Thread.interrupted()) { |
| throw ie; |
| } |
| } |
| } |
| } |
| } |
| |
| boolean isDone() { |
| return done.get(); |
| } |
| |
| // invoked by ipc handler |
| @Override |
| public final Void run() throws IOException { |
| try { |
| result = action.run(); |
| sendResponse(); |
| } catch (Throwable t) { |
| abortResponse(t); |
| } |
| return null; |
| } |
| |
| @Override |
| final void doResponse(Throwable t, RpcStatusProto status) { |
| synchronized(done) { |
| error = t; |
| done.set(true); |
| done.notify(); |
| } |
| } |
| } |