br.com.caelum.vraptor.cache.CacheStoreFactory.java Source code

Introduction

Here is the source code for br.com.caelum.vraptor.cache.CacheStoreFactory.java

Source

/***
 * Copyright (c) 2009 Caelum - www.caelum.com.br/opensource All rights reserved.
 *
 * 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 br.com.caelum.vraptor.cache;

import static com.google.common.base.Throwables.propagateIfPossible;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;

import javax.enterprise.context.Dependent;
import javax.enterprise.inject.Default;
import javax.enterprise.inject.Produces;
import javax.enterprise.inject.spi.InjectionPoint;

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

/**
 * A factory class that produces cache implementations.
 * 
 * @author Alberto Souza
 * @author Otvio S Garcia
 */
@Dependent
public class CacheStoreFactory {

    @Produces
    @Default
    public <K, V> CacheStore<K, V> buildDefaultCache() {
        return new DefaultCacheStore<>();
    }

    @Produces
    @LRU
    public <K, V> CacheStore<K, V> buildLRUCache(InjectionPoint ip) {
        int capacity = ip.getAnnotated().getAnnotation(LRU.class).capacity();
        return createCacheWrapper(capacity);
    }

    public <V, K> CacheStore<K, V> createCacheWrapper(int capacity) {
        Cache<K, V> guavaCache = CacheBuilder.newBuilder().maximumSize(capacity).build();
        return new GuavaCacheWrapper<>(guavaCache);
    }

    public static class GuavaCacheWrapper<K, V> implements CacheStore<K, V> {

        private Cache<K, V> guavaCache;

        public GuavaCacheWrapper(Cache<K, V> guavaCache) {
            this.guavaCache = guavaCache;
        }

        @Override
        public V write(K key, V value) {
            guavaCache.put(key, value);
            return value;
        }

        @Override
        public V fetch(K key) {
            return guavaCache.getIfPresent(key);
        }

        @Override
        public V fetch(K key, Supplier<V> valueProvider) {
            final Supplier<V> userSuplier = valueProvider;
            try {
                return guavaCache.get(key, new Callable<V>() {

                    @Override
                    public V call() throws Exception {
                        return userSuplier.get();
                    }
                });
            } catch (ExecutionException e) {
                throw new CacheException("Error while trying to fetch key: " + key, e);
            }
        }
    }
}