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/*
* Copyright (C) 2006 The Guava Authors
*
* 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.common.util.concurrent;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.annotations.GwtCompatible;
import com.google.common.util.concurrent.AbstractFuture.TrustedFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/** Implementation of {@link Futures#immediateFuture}. */
@GwtCompatible
@ElementTypesAreNonnullByDefault
// TODO(cpovirk): Make this final (but that may break Mockito spy calls).
class ImmediateFuture<V extends @Nullable Object> implements ListenableFuture<V> {
static final ListenableFuture<?> NULL = new ImmediateFuture<@Nullable Object>(null);
private static final LazyLogger log = new LazyLogger(ImmediateFuture.class);
@ParametricNullness private final V value;
ImmediateFuture(@ParametricNullness V value) {
this.value = value;
}
@Override
@SuppressWarnings("CatchingUnchecked") // sneaky checked exception
public void addListener(Runnable listener, Executor executor) {
checkNotNull(listener, "Runnable was null.");
checkNotNull(executor, "Executor was null.");
try {
executor.execute(listener);
} catch (Exception e) { // sneaky checked exception
// ListenableFuture's contract is that it will not throw unchecked exceptions, so log the bad
// runnable and/or executor and swallow it.
log.get()
.log(
Level.SEVERE,
"RuntimeException while executing runnable "
+ listener
+ " with executor "
+ executor,
e);
}
}
@Override
public boolean cancel(boolean mayInterruptIfRunning) {
return false;
}
// TODO(lukes): Consider throwing InterruptedException when appropriate.
@Override
@ParametricNullness
public V get() {
return value;
}
@Override
@ParametricNullness
public V get(long timeout, TimeUnit unit) throws ExecutionException {
checkNotNull(unit);
return get();
}
@Override
public boolean isCancelled() {
return false;
}
@Override
public boolean isDone() {
return true;
}
@Override
public String toString() {
// Behaviour analogous to AbstractFuture#toString().
return super.toString() + "[status=SUCCESS, result=[" + value + "]]";
}
static final class ImmediateFailedFuture<V extends @Nullable Object> extends TrustedFuture<V> {
ImmediateFailedFuture(Throwable thrown) {
setException(thrown);
}
}
static final class ImmediateCancelledFuture<V extends @Nullable Object> extends TrustedFuture<V> {
@CheckForNull
static final ImmediateCancelledFuture<Object> INSTANCE =
AbstractFuture.GENERATE_CANCELLATION_CAUSES ? null : new ImmediateCancelledFuture<>();
ImmediateCancelledFuture() {
cancel(false);
}
}
}
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