opendaylight/md-sal/sal-dom-compat/src/main/java/org/opendaylight/controller/sal/core/compat/AbstractDOMRpcResultFutureAdapter.java

   1 /*
   2  * Copyright (c) 2018 Inocybe Technologies and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.controller.sal.core.compat;
   9
  10 import com.google.common.util.concurrent.AbstractFuture;
  11 import com.google.common.util.concurrent.ListenableFuture;
  12 import java.util.Optional;
  13 import java.util.concurrent.ExecutionException;
  14 import java.util.concurrent.Executor;
  15 import java.util.concurrent.TimeUnit;
  16 import java.util.concurrent.TimeoutException;
  17 import org.opendaylight.mdsal.dom.api.DOMRpcException;
  18 import org.opendaylight.mdsal.dom.api.DOMRpcResult;
  19 import org.opendaylight.yangtools.util.concurrent.ExceptionMapper;
  20
  21 /**
  22  * Base for a DOMRpcResult future adapter.
  23  *
  24  * @author Thomas Pantelis
  25  */
  26 @SuppressWarnings("checkstyle:ClassTypeParameterName")
  27 public abstract class AbstractDOMRpcResultFutureAdapter<T extends DOMRpcResult, F extends DOMRpcResult,
  28         D extends ListenableFuture<F>, E extends DOMRpcException> extends AbstractFuture<T> {
  29     private final D delegate;
  30     private final ExceptionMapper<E> exMapper;
  31     private volatile Optional<T> result;
  32
  33     AbstractDOMRpcResultFutureAdapter(D delegate, ExceptionMapper<E> exMapper) {
  34         this.delegate = delegate;
  35         this.exMapper = exMapper;
  36     }
  37
  38     protected abstract T transform(F fromResult);
  39
  40     public D delegate() {
  41         return delegate;
  42     }
  43
  44     @Override
  45     public void addListener(Runnable listener, Executor executor) {
  46         delegate.addListener(listener, executor);
  47     }
  48
  49     @Override
  50     public boolean cancel(boolean mayInterruptIfRunning) {
  51         return delegate.cancel(mayInterruptIfRunning);
  52     }
  53
  54     @Override
  55     public boolean isCancelled() {
  56         return delegate.isCancelled();
  57     }
  58
  59     @Override
  60     public boolean isDone() {
  61         return delegate.isDone();
  62     }
  63
  64     @Override
  65     public T get() throws InterruptedException, ExecutionException {
  66         if (result != null) {
  67             return result.orElse(null);
  68         }
  69
  70         try {
  71             return transformIfNecessary(delegate.get());
  72         } catch (ExecutionException e) {
  73             throw new ExecutionException(e.getMessage(), exMapper.apply(e));
  74         }
  75     }
  76
  77     @Override
  78     public T get(final long timeout, final TimeUnit unit) throws InterruptedException, ExecutionException,
  79             TimeoutException {
  80         if (result != null) {
  81             return result.orElse(null);
  82         }
  83
  84         try {
  85             return transformIfNecessary(delegate.get(timeout, unit));
  86         } catch (ExecutionException e) {
  87             throw new ExecutionException(e.getMessage(), exMapper.apply(e));
  88         }
  89     }
  90
  91     private synchronized T transformIfNecessary(F delegateResult) {
  92         if (result == null) {
  93             if (delegateResult == null) {
  94                 result = Optional.empty();
  95             } else {
  96                 result = Optional.of(transform(delegateResult));
  97             }
  98         }
  99
 100         return result.orElse(null);
 101     }
 102 }