/*
* 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.jena.atlas.lib;
import java.util.Iterator ;
import java.util.concurrent.Callable ;
import java.util.function.BiConsumer;
/** A cache */
public interface Cache<Key, Value>
{
/** Does the cache contain the key? */
public boolean containsKey(Key key) ;
/** Get from cache - or return null. */
public Value getIfPresent(Key key) ;
/** Get from cache, of not present, call the {@code callable}
* to try to fill the cache. This operation should be atomic.
*/
public Value getOrFill(Key key, Callable<Value> callable) ;
/** Insert into the cache */
public void put(Key key, Value thing) ;
/** Remove from cache - return true if key referenced an entry */
public void remove(Key key) ;
/** Iterate over all keys. Iteratering over the keys requires the caller be thread-safe. */
public Iterator<Key> keys() ;
public boolean isEmpty() ;
public void clear() ;
/** Current size of cache */
public long size() ;
/** Register a callback - called when an object is dropped from the cache (optional operation) */
public void setDropHandler(BiConsumer<Key,Value> dropHandler) ;
}