diff options
Diffstat (limited to 'guava/src/com/google/common/cache/RemovalNotification.java')
-rw-r--r-- | guava/src/com/google/common/cache/RemovalNotification.java | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/guava/src/com/google/common/cache/RemovalNotification.java b/guava/src/com/google/common/cache/RemovalNotification.java new file mode 100644 index 0000000..8e0066e --- /dev/null +++ b/guava/src/com/google/common/cache/RemovalNotification.java @@ -0,0 +1,100 @@ +/* + * 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.Beta; +import com.google.common.base.Objects; + +import java.util.Map.Entry; + +import javax.annotation.Nullable; + +/** + * A notification of the removal of a single entry. The key and/or value may be null if they were + * already garbage collected. + * + * <p>Like other {@code Map.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 + */ +@Beta +public final class RemovalNotification<K, V> implements Entry<K, V> { + @Nullable private final K key; + @Nullable private final V value; + private final RemovalCause cause; + + RemovalNotification(@Nullable K key, @Nullable V value, RemovalCause cause) { + this.key = key; + this.value = 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(); + } + + @Nullable @Override public K getKey() { + return key; + } + + @Nullable @Override public V getValue() { + return value; + } + + @Override public final V setValue(V value){ + throw new UnsupportedOperationException(); + } + + @Override public boolean equals(@Nullable Object object) { + if (object instanceof Entry) { + Entry<?, ?> that = (Entry<?, ?>) object; + return Objects.equal(this.getKey(), that.getKey()) + && Objects.equal(this.getValue(), that.getValue()); + } + return false; + } + + @Override public int hashCode() { + K k = getKey(); + V v = getValue(); + return ((k == null) ? 0 : k.hashCode()) ^ ((v == null) ? 0 : v.hashCode()); + } + + /** + * Returns a string representation of the form <code>{key}={value}</code>. + */ + @Override public String toString() { + return getKey() + "=" + getValue(); + } + private static final long serialVersionUID = 0; +} |