//   Copyright 2012 Georg-August-Universität Göttingen, Germany
//
//   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 de.ugoe.cs.autoquest.usability.tasktree.filter;

import java.util.concurrent.TimeUnit;

import com.google.common.base.Optional;
import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;

/**
 * <p>
 * TODO comment
 * </p>
 * 
 * @author Alexander Deicke
 */
public class FilterStatisticCache {

    private static final FilterStatisticCache instance = new FilterStatisticCache();

    @SuppressWarnings("rawtypes")
    private Cache<TaskTreeNodeFilter, FilterStatistic> cache;

    private FilterStatisticCache() {
        this.cache = CacheBuilder.newBuilder().expireAfterWrite(10, TimeUnit.MINUTES).build();
    }

    public static FilterStatisticCache instance() {
        return instance;
    }

    @SuppressWarnings("rawtypes")
    public void addFilterStatistic(TaskTreeNodeFilter nodeFilter, FilterStatistic filterStatistic) {
        this.cache.put(nodeFilter, filterStatistic);
    }

    @SuppressWarnings("rawtypes")
    public Optional<FilterStatistic> getFilterStatistic(TaskTreeNodeFilter nodeFilter) {
        return Optional.fromNullable(this.cache.getIfPresent(nodeFilter));
    }

    public void clear() {
        this.cache.invalidateAll();
    }

}