/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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 org.apache.kafka.streams.state.internals;
import org.apache.kafka.common.serialization.Serde;
import org.apache.kafka.streams.KeyValue;
import org.apache.kafka.streams.state.KeyValueIterator;
import java.util.Iterator;
import java.util.Map;
import java.util.TreeMap;
public class MemoryNavigableLRUCache<K, V> extends MemoryLRUCache<K, V> {
public MemoryNavigableLRUCache(String name, final int maxCacheSize, Serde<K> keySerde, Serde<V> valueSerde) {
super(name, maxCacheSize, keySerde, valueSerde);
}
@Override
public MemoryNavigableLRUCache<K, V> whenEldestRemoved(EldestEntryRemovalListener<K, V> listener) {
this.listener = listener;
return this;
}
@Override
public KeyValueIterator<K, V> range(K from, K to) {
final TreeMap<K, V> treeMap = toTreeMap();
return new DelegatingPeekingKeyValueIterator<>(name(), new MemoryNavigableLRUCache.CacheIterator<>(treeMap.navigableKeySet().subSet(from, true, to, true).iterator(), treeMap));
}
@Override
public KeyValueIterator<K, V> all() {
final TreeMap<K, V> treeMap = toTreeMap();
return new MemoryNavigableLRUCache.CacheIterator<>(treeMap.navigableKeySet().iterator(), treeMap);
}
private synchronized TreeMap<K, V> toTreeMap() {
return new TreeMap<>(this.map);
}
private static class CacheIterator<K, V> implements KeyValueIterator<K, V> {
private final Iterator<K> keys;
private final Map<K, V> entries;
private K lastKey;
public CacheIterator(Iterator<K> keys, Map<K, V> entries) {
this.keys = keys;
this.entries = entries;
}
@Override
public boolean hasNext() {
return keys.hasNext();
}
@Override
public KeyValue<K, V> next() {
lastKey = keys.next();
return new KeyValue<>(lastKey, entries.get(lastKey));
}
@Override
public void remove() {
// do nothing
}
@Override
public void close() {
// do nothing
}
@Override
public K peekNextKey() {
throw new UnsupportedOperationException("peekNextKey not supported");
}
}
}