com.google.common.cache.RemovalNotification Maven / Gradle / Ivy
/*
* Copyright (C) 2011 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.cache;
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.annotations.GwtCompatible;
import java.util.AbstractMap.SimpleImmutableEntry;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;
/**
* A notification of the removal of a single entry. The key and/or value may be null if they were
* already garbage collected.
*
* Like other {@code Entry} instances associated with {@code CacheBuilder}, this class holds
* strong references to the key and value, regardless of the type of references the cache may be
* using.
*
* @author Charles Fry
* @since 10.0
*/
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class RemovalNotification
extends SimpleImmutableEntry<@Nullable K, @Nullable V> {
private final RemovalCause cause;
/**
* Creates a new {@code RemovalNotification} for the given {@code key}/{@code value} pair, with
* the given {@code cause} for the removal. The {@code key} and/or {@code value} may be {@code
* null} if they were already garbage collected.
*
* @since 19.0
*/
public static RemovalNotification create(
@CheckForNull K key, @CheckForNull V value, RemovalCause cause) {
return new RemovalNotification<>(key, value, cause);
}
private RemovalNotification(@CheckForNull K key, @CheckForNull V value, RemovalCause cause) {
super(key, value);
this.cause = checkNotNull(cause);
}
/** Returns the cause for which the entry was removed. */
public RemovalCause getCause() {
return cause;
}
/**
* Returns {@code true} if there was an automatic removal due to eviction (the cause is neither
* {@link RemovalCause#EXPLICIT} nor {@link RemovalCause#REPLACED}).
*/
public boolean wasEvicted() {
return cause.wasEvicted();
}
private static final long serialVersionUID = 0;
}