/*

  * 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.giraph.utils;

 import java.util.concurrent.Callable;

 import org.apache.log4j.Logger;

 /**

  * A wrapper to improve debugging. It passes the call() invocation to the

  * provided callable, and upon any exception logs the stacktrace and rethrows

  * the exception. The logging functionality is missing in FutureTask.

  *

  * @param <V> Return type of call()

  */

 public class LogStacktraceCallable<V> implements Callable<V> {

   /** Class logger */

   private static final Logger LOG =

       Logger.getLogger(LogStacktraceCallable.class);

   /** Pass call() to this callable. */

   private final Callable<V> callable;

   /** Uncaught exception handler, if any */

   private final Thread.UncaughtExceptionHandler uncaughtExceptionHandler;

   /**

    * Construct an instance that will pass call() to the given callable.

    *

    * @param callable Callable

    */

   public LogStacktraceCallable(Callable<V> callable) {

     this(callable, null);

   }

   /**

    * Construct an instance that will pass call() to the given callable.

    *

    * @param callable Callable

    * @param uncaughtExceptionHandler Uncaught exception handler, if any

    *

    *

    */

   public LogStacktraceCallable(Callable<V> callable,

       Thread.UncaughtExceptionHandler uncaughtExceptionHandler) {

     this.callable = callable;

     this.uncaughtExceptionHandler = uncaughtExceptionHandler;

   }

   @Override

   public V call() throws Exception {

     try {

       return callable.call();

       // We catch, log stack trace of, and rethrow all exceptions. It's OK to

       // skip style check.

       // CHECKSTYLE: stop IllegalCatch

     } catch (Exception e) {

       // CHECKSTYLE: resume IllegalCatch

       LOG.error("Execution of callable failed", e);

       if (uncaughtExceptionHandler != null) {

         uncaughtExceptionHandler.uncaughtException(Thread.currentThread(), e);

       }

       throw e;

     }

   }

 }