/*
 * 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.cache;

import java.util.Iterator;
import java.util.function.Function;

import org.apache.jena.atlas.iterator.Iter;
import org.apache.jena.atlas.lib.Cache;

/** A cache that keeps nothing */
public final class Cache0<K, V> implements Cache<K, V> {
    @Override
    public boolean containsKey(K key) {
        return false;
    }

    @Override
    public V getIfPresent(K key) {
        return null;
    }

    @Override
    public V get(K key, Function<K, V> function) {
        return function.apply(key);
    }

    @Override
    public void put(K key, V thing) {}

    @Override
    public void remove(K key) {}

    @Override
    public Iterator<K> keys() {
        return Iter.nullIterator();
    }

    @Override
    public boolean isEmpty() {
        return true;
    }

    @Override
    public void clear() {}

    @Override
    public long size() {
        return 0;
    }
}
