001/**
002 * Copyright (C) 2006-2020 Talend Inc. - www.talend.com
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016package org.talend.sdk.component.server.lang;
017
018import java.util.Iterator;
019import java.util.Map;
020import java.util.concurrent.ConcurrentMap;
021
022import javax.enterprise.context.ApplicationScoped;
023
024@ApplicationScoped
025public class MapCache {
026
027    // simple - but enough - protection against too much entries in the cache
028    // this mainly targets ?query king of parameters
029    public <A, B> void evictIfNeeded(final ConcurrentMap<A, B> cache, final int maxSize) {
030        if (maxSize < 0) {
031            cache.clear();
032            return;
033        }
034        while (cache.size() > maxSize) {
035            final Iterator<Map.Entry<A, B>> iterator = cache.entrySet().iterator();
036            if (iterator.hasNext()) {
037                iterator.remove();
038            }
039        }
040    }
041}