/*
    * Copyright 2013 The Netty Project
    *
    * The Netty Project 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 io.netty.util.concurrent;
  
  import java.util.concurrent.Callable;
  import java.util.concurrent.RunnableFuture;
  
  class PromiseTask<V> extends DefaultPromise<V> implements RunnableFuture<V> {
  
      static <T> Callable<T> toCallable(Runnable runnable, T result) {
          return new RunnableAdapter<T>(runnable, result);
      }
  
      private static final class RunnableAdapter<T> implements Callable<T> {
          final Runnable task;
          final T result;
  
          RunnableAdapter(Runnable task, T result) {
              this.task = task;
              this.result = result;
          }
  
          @Override
          public T call() {
              task.run();
              return result;
          }
  
          @Override
          public String toString() {
              return "Callable(task: " + task + ", result: " + result + ')';
          }
      }
  
      protected final Callable<V> task;
  
      PromiseTask(EventExecutor executor, Runnable runnable, V result) {
          this(executor, toCallable(runnable, result));
      }
  
      PromiseTask(EventExecutor executor, Callable<V> callable) {
          super(executor);
          task = callable;
      }
  
      @Override
      public final int hashCode() {
          return System.identityHashCode(this);
      }
  
      @Override
      public final boolean equals(Object obj) {
          return this == obj;
      }
  
      @Override
      public void run() {
          try {
              if (setUncancellableInternal()) {
                  V result = task.call();
                  setSuccessInternal(result);
              }
          } catch (Throwable e) {
              setFailureInternal(e);
          }
      }
  
      @Override
      public final Promise<V> setFailure(Throwable cause) {
          throw new IllegalStateException();
      }
  
      protected final Promise<V> setFailureInternal(Throwable cause) {
          super.setFailure(cause);
          return this;
      }
  
      @Override
      public final boolean tryFailure(Throwable cause) {
          return false;
      }
  
      protected final boolean tryFailureInternal(Throwable cause) {
          return super.tryFailure(cause);
      }
  
     @Override
     public final Promise<V> setSuccess(V result) {
         throw new IllegalStateException();
     }
 
     protected final Promise<V> setSuccessInternal(V result) {
         super.setSuccess(result);
         return this;
     }
 
     @Override
     public final boolean trySuccess(V result) {
         return false;
     }
 
     protected final boolean trySuccessInternal(V result) {
         return super.trySuccess(result);
     }
 
     @Override
     public final boolean setUncancellable() {
         throw new IllegalStateException();
     }
 
     protected final boolean setUncancellableInternal() {
         return super.setUncancellable();
     }
 
     @Override
     protected StringBuilder toStringBuilder() {
         StringBuilder buf = super.toStringBuilder();
         buf.setCharAt(buf.length() - 1, ',');
 
         return buf.append(" task: ")
                   .append(task)
                   .append(')');
     }
 }