Add caching support for Caffeine

Issue: SPR-13690

spring-context-support/src/main/java/org/springframework/cache/caffeine/CaffeineCache.java

@@ -0,0 +1,136 @@
+/*
+ * Copyright 2002-2015 the original author or authors.
+ *
+ * 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 org.springframework.cache.caffeine;
+
+import java.util.function.Function;
+
+import org.springframework.cache.support.AbstractValueAdaptingCache;
+import org.springframework.util.Assert;
+
+import com.github.benmanes.caffeine.cache.LoadingCache;
+
+/**
+ * Spring {@link org.springframework.cache.Cache} adapter implementation
+ * on top of a Caffeine {@link com.github.benmanes.caffeine.cache.Cache} instance.
+ *
+ * <p>Requires Caffeine 2.0 or higher.
+ *
+ * @author Juergen Hoeller
+ * @author Stephane Nicoll
+ * @author Ben Manes
+ * @since 4.0
+ */
+public class CaffeineCache extends AbstractValueAdaptingCache {
+
+	private final String name;
+
+	private final com.github.benmanes.caffeine.cache.Cache<Object, Object> cache;
+
+
+	/**
+	 * Create a {@link CaffeineCache} instance with the specified name and the
+	 * given internal {@link com.github.benmanes.caffeine.cache.Cache} to use.
+	 * @param name the name of the cache
+	 * @param cache the backing Caffeine Cache instance
+	 */
+	public CaffeineCache(String name, com.github.benmanes.caffeine.cache.Cache<Object, Object> cache) {
+		this(name, cache, true);
+	}
+
+	/**
+	 * Create a {@link CaffeineCache} instance with the specified name and the
+	 * given internal {@link com.github.benmanes.caffeine.cache.Cache} to use.
+	 * @param name the name of the cache
+	 * @param cache the backing Caffeine Cache instance
+	 * @param allowNullValues whether to accept and convert {@code null}
+	 * values for this cache
+	 */
+	public CaffeineCache(String name, com.github.benmanes.caffeine.cache.Cache<Object, Object> cache,
+			boolean allowNullValues) {
+		super(allowNullValues);
+		Assert.notNull(name, "Name must not be null");
+		Assert.notNull(cache, "Cache must not be null");
+		this.name = name;
+		this.cache = cache;
+	}
+
+
+	@Override
+	public final String getName() {
+		return this.name;
+	}
+
+	@Override
+	public final com.github.benmanes.caffeine.cache.Cache<Object, Object> getNativeCache() {
+		return this.cache;
+	}
+
+	@Override
+	public ValueWrapper get(Object key) {
+		if (this.cache instanceof LoadingCache) {
+			Object value = ((LoadingCache<Object, Object>) this.cache).get(key);
+			return toValueWrapper(value);
+		}
+		return super.get(key);
+	}
+
+	@Override
+	protected Object lookup(Object key) {
+		return this.cache.getIfPresent(key);
+	}
+
+	@Override
+	public void put(Object key, Object value) {
+		this.cache.put(key, toStoreValue(value));
+	}
+
+	@Override
+	public ValueWrapper putIfAbsent(Object key, final Object value) {
+		PutIfAbsentFunction callable = new PutIfAbsentFunction(value);
+		Object result = this.cache.get(key, callable);
+		return (callable.called ? null : toValueWrapper(result));
+	}
+
+	@Override
+	public void evict(Object key) {
+		this.cache.invalidate(key);
+	}
+
+	@Override
+	public void clear() {
+		this.cache.invalidateAll();
+	}
+
+
+	private class PutIfAbsentFunction implements Function<Object, Object> {
+
+		private final Object value;
+
+		private boolean called;
+
+		public PutIfAbsentFunction(Object value) {
+			this.value = value;
+		}
+
+		@Override
+		public Object apply(Object key) {
+			this.called = true;
+			return toStoreValue(this.value);
+		}
+	}
+
+}

spring-context-support/src/main/java/org/springframework/cache/caffeine/CaffeineCacheManager.java

@@ -0,0 +1,206 @@
+/*
+ * Copyright 2002-2014 the original author or authors.
+ *
+ * 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 org.springframework.cache.caffeine;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+import org.springframework.cache.Cache;
+import org.springframework.cache.CacheManager;
+import org.springframework.util.Assert;
+import org.springframework.util.ObjectUtils;
+
+import com.github.benmanes.caffeine.cache.CacheLoader;
+import com.github.benmanes.caffeine.cache.Caffeine;
+
+/**
+ * {@link CacheManager} implementation that lazily builds {@link CaffeineCache}
+ * instances for each {@link #getCache} request. Also supports a 'static' mode
+ * where the set of cache names is pre-defined through {@link #setCacheNames},
+ * with no dynamic creation of further cache regions at runtime.
+ *
+ * <p>The configuration of the underlying cache can be fine-tuned through a
+ * {@link Caffeine} builder, passed into this CacheManager through
+ * {@link #setCaffeine}.
+ *
+ * <p>Requires Caffeine 2.0 or higher.
+ *
+ * @author Juergen Hoeller
+ * @author Stephane Nicoll
+ * @author Ben Manes
+ * @since 4.0
+ * @see CaffeineCache
+ */
+public class CaffeineCacheManager implements CacheManager {
+
+	private final ConcurrentMap<String, Cache> cacheMap = new ConcurrentHashMap<String, Cache>(16);
+
+	private boolean dynamic = true;
+
+	private Caffeine<Object, Object> cacheBuilder = Caffeine.newBuilder();
+
+	private CacheLoader<Object, Object> cacheLoader;
+
+	private boolean allowNullValues = true;
+
+
+	/**
+	 * Construct a dynamic CaffeineCacheManager,
+	 * lazily creating cache instances as they are being requested.
+	 */
+	public CaffeineCacheManager() {
+	}
+
+	/**
+	 * Construct a static CaffeineCacheManager,
+	 * managing caches for the specified cache names only.
+	 */
+	public CaffeineCacheManager(String... cacheNames) {
+		setCacheNames(Arrays.asList(cacheNames));
+	}
+
+
+	/**
+	 * Specify the set of cache names for this CacheManager's 'static' mode.
+	 * <p>The number of caches and their names will be fixed after a call to this method,
+	 * with no creation of further cache regions at runtime.
+	 * <p>Calling this with a {@code null} collection argument resets the
+	 * mode to 'dynamic', allowing for further creation of caches again.
+	 */
+	public void setCacheNames(Collection<String> cacheNames) {
+		if (cacheNames != null) {
+			for (String name : cacheNames) {
+				this.cacheMap.put(name, createCaffeineCache(name));
+			}
+			this.dynamic = false;
+		}
+		else {
+			this.dynamic = true;
+		}
+	}
+
+	/**
+	 * Set the Caffeine to use for building each individual
+	 * {@link CaffeineCache} instance.
+	 * @see #createNativeCaffeineCache
+	 * @see com.github.benmanes.caffeine.cache.CacheBuilder#build()
+	 */
+	public void setCaffeine(Caffeine<Object, Object> cacheBuilder) {
+		Assert.notNull(cacheBuilder, "Caffeine must not be null");
+		doSetCaffeine(cacheBuilder);
+	}
+
+	/**
+	 * Set the Caffeine CacheLoader to use for building each individual
+	 * {@link CaffeineCache} instance, turning it into a LoadingCache.
+	 * @see #createNativeCaffeineCache
+	 * @see com.github.benmanes.caffeine.cache.Caffeine#build(CacheLoader)
+	 * @see com.github.benmanes.caffeine.cache.LoadingCache
+	 */
+	public void setCacheLoader(CacheLoader<Object, Object> cacheLoader) {
+		if (!ObjectUtils.nullSafeEquals(this.cacheLoader, cacheLoader)) {
+			this.cacheLoader = cacheLoader;
+			refreshKnownCaches();
+		}
+	}
+
+	/**
+	 * Specify whether to accept and convert {@code null} values for all caches
+	 * in this cache manager.
+	 * <p>Default is "true", despite Caffeine itself not supporting {@code null} values.
+	 * An internal holder object will be used to store user-level {@code null}s.
+	 */
+	public void setAllowNullValues(boolean allowNullValues) {
+		if (this.allowNullValues != allowNullValues) {
+			this.allowNullValues = allowNullValues;
+			refreshKnownCaches();
+		}
+	}
+
+	/**
+	 * Return whether this cache manager accepts and converts {@code null} values
+	 * for all of its caches.
+	 */
+	public boolean isAllowNullValues() {
+		return this.allowNullValues;
+	}
+
+
+	@Override
+	public Collection<String> getCacheNames() {
+		return Collections.unmodifiableSet(this.cacheMap.keySet());
+	}
+
+	@Override
+	public Cache getCache(String name) {
+		Cache cache = this.cacheMap.get(name);
+		if (cache == null && this.dynamic) {
+			synchronized (this.cacheMap) {
+				cache = this.cacheMap.get(name);
+				if (cache == null) {
+					cache = createCaffeineCache(name);
+					this.cacheMap.put(name, cache);
+				}
+			}
+		}
+		return cache;
+	}
+
+	/**
+	 * Create a new CaffeineCache instance for the specified cache name.
+	 * @param name the name of the cache
+	 * @return the Spring CaffeineCache adapter (or a decorator thereof)
+	 */
+	protected Cache createCaffeineCache(String name) {
+		return new CaffeineCache(name, createNativeCaffeineCache(name), isAllowNullValues());
+	}
+
+	/**
+	 * Create a native Caffeine Cache instance for the specified cache name.
+	 * @param name the name of the cache
+	 * @return the native Caffeine Cache instance
+	 */
+	protected com.github.benmanes.caffeine.cache.Cache<Object, Object> createNativeCaffeineCache(String name) {
+		if (this.cacheLoader != null) {
+			return this.cacheBuilder.build(this.cacheLoader);
+		}
+		else {
+			return this.cacheBuilder.build();
+		}
+	}
+
+	private void doSetCaffeine(Caffeine<Object, Object> cacheBuilder) {
+		if (!ObjectUtils.nullSafeEquals(this.cacheBuilder, cacheBuilder)) {
+			this.cacheBuilder = cacheBuilder;
+			refreshKnownCaches();
+		}
+	}
+
+	/**
+	 * Create the known caches again with the current state of this manager.
+	 */
+	private void refreshKnownCaches() {
+		for (Map.Entry<String, Cache> entry : this.cacheMap.entrySet()) {
+			entry.setValue(createCaffeineCache(entry.getKey()));
+		}
+	}
+
+}

spring-context-support/src/main/java/org/springframework/cache/caffeine/package-info.java

@@ -0,0 +1,6 @@
+/**
+ * Support classes for the open source cache in
+ * <a href="https://github.com/ben-manes/caffeine/">Caffeine</a> library,
+ * allowing to set up Caffeine caches within Spring's cache abstraction.
+ */
+package org.springframework.cache.caffeine;