no.digipost.cache.inmemory.Cache.java Source code

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Here is the source code for no.digipost.cache.inmemory.Cache.java

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/**
 * Copyright (C) Posten Norge AS
 *
 * 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 no.digipost.cache.inmemory;

import com.google.common.cache.CacheBuilder;
import no.digipost.cache.loader.Callables;
import no.digipost.cache.loader.Loader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

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

import static java.util.Arrays.asList;
import static no.digipost.cache.inmemory.CacheConfig.jodaTicker;
import static no.digipost.cache.inmemory.CacheConfig.logRemoval;
import static no.motif.Iterate.on;

/**
 * Wrapper around {@link com.google.common.cache.Cache} from the Guava
 * library.
 */
public final class Cache<K, V> {

    static final Logger LOG = LoggerFactory.getLogger(Cache.class);

    private com.google.common.cache.Cache<K, V> guavaCache;
    private String name;

    public Cache(CacheConfig... configurers) {
        this(asList(configurers));
    }

    public Cache(String name, CacheConfig... configurers) {
        this(name, asList(configurers));
    }

    public Cache(Iterable<CacheConfig> configurers) {
        this("cache-" + UUID.randomUUID(), configurers);
    }

    public Cache(String name, Iterable<CacheConfig> configurers) {
        LOG.info("Creating new cache: {}", name);
        this.guavaCache = on(configurers).append(jodaTicker).append(logRemoval)
                .reduce(CacheBuilder.newBuilder(), ConfiguresGuavaCache.applyConfiguration).build();
        this.name = name;
    }

    /**
     * Retrieve a possibly cached value from the cache, or use the provided
     * {@code valueResolver} if the cache does not contain any value for the given
     * key.
     */
    public V get(final K key, final Callable<V> valueResolver) {
        return get(key, Callables.toLoader(valueResolver));
    }

    /**
     * Retrieve a possibly cached value from the cache, or use the provided
     * {@link Loader valueResolver} if the cache does not contain any value for the given
     * key.
     */
    public V get(final K key, final Loader<? super K, V> valueResolver) {
        try {
            return guavaCache.get(key, new Callable<V>() {
                @Override
                public V call() throws Exception {
                    LOG.debug("{} resolving value for key {}", name, key);
                    V value = valueResolver.load(key);
                    LOG.info("Loaded '{}' into '{}' cache for key '{}'", value, name, key);
                    return value;
                }
            });
        } catch (ExecutionException e) {
            throw new RuntimeException(e.getMessage(), e);
        }
    }

    public void invalidateAll() {
        LOG.debug("Invalidating all in {} cache", name);
        guavaCache.invalidateAll();
    }

    @SafeVarargs
    public final void invalidate(K... keys) {
        invalidate(asList(keys));
    }

    public void invalidate(Iterable<? extends K> keys) {
        LOG.debug("Invalidating specific keys in {} cache", name);
        guavaCache.invalidateAll(keys);
    }

    public CacheStats getCacheStats() {
        return CacheStats.fromGuava(guavaCache.stats());
    }

}