diff --git a/spring-context/src/main/java/org/springframework/cache/support/CompositeCacheManager.java b/spring-context/src/main/java/org/springframework/cache/support/CompositeCacheManager.java index 3d64b770e0..eac12fd820 100644 --- a/spring-context/src/main/java/org/springframework/cache/support/CompositeCacheManager.java +++ b/spring-context/src/main/java/org/springframework/cache/support/CompositeCacheManager.java @@ -1,5 +1,5 @@ /* - * Copyright 2002-2012 the original author or authors. + * 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. @@ -17,42 +17,72 @@ package org.springframework.cache.support; import java.util.ArrayList; +import java.util.Arrays; import java.util.Collection; import java.util.Collections; +import java.util.LinkedHashSet; import java.util.List; +import java.util.Set; import org.springframework.beans.factory.InitializingBean; import org.springframework.cache.Cache; import org.springframework.cache.CacheManager; -import org.springframework.util.Assert; /** - * Composite {@link CacheManager} implementation that iterates - * over a given collection of {@link CacheManager} instances. + * Composite {@link CacheManager} implementation that iterates over + * a given collection of delegate {@link CacheManager} instances. * - * Allows {@link NoOpCacheManager} to be automatically added to the list for handling - * the cache declarations without a backing store. + *

Allows {@link NoOpCacheManager} to be automatically added to the end of + * the list for handling cache declarations without a backing store. Otherwise, + * any custom {@link CacheManager} may play that role of the last delegate as + * well, lazily creating cache regions for any requested name. + * + *

Note: Regular CacheManagers that this composite manager delegates to need + * to return {@code null} from {@link #getCache(String)} if they are unaware of + * the specified cache name, allowing for iteration to the next delegate in line. + * However, most {@link CacheManager} implementations fall back to lazy creation + * of named caches once requested; check out the specific configuration details + * for a 'static' mode with fixed cache names, if available. * * @author Costin Leau * @author Juergen Hoeller * @since 3.1 + * @see #setFallbackToNoOpCache + * @see org.springframework.cache.concurrent.ConcurrentMapCacheManager#setCacheNames */ -public class CompositeCacheManager implements InitializingBean, CacheManager { +public class CompositeCacheManager implements CacheManager, InitializingBean { - private List cacheManagers; + private final List cacheManagers = new ArrayList(); private boolean fallbackToNoOpCache = false; + /** + * Construct an empty CompositeCacheManager, with delegate CacheManagers to + * be added via the {@link #setCacheManagers "cacheManagers"} property. + */ + public CompositeCacheManager() { + } + + /** + * Construct a CompositeCacheManager from the given delegate CacheManagers. + * @param cacheManagers the CacheManagers to delegate to + */ + public CompositeCacheManager(CacheManager... cacheManagers) { + setCacheManagers(Arrays.asList(cacheManagers)); + } + + + /** + * Specify the CacheManagers to delegate to. + */ public void setCacheManagers(Collection cacheManagers) { - Assert.notEmpty(cacheManagers, "cacheManagers Collection must not be empty"); - this.cacheManagers = new ArrayList(); this.cacheManagers.addAll(cacheManagers); } /** - * Indicate whether a {@link NoOpCacheManager} should be added at the end of the manager lists. - * In this case, any {@code getCache} requests not handled by the configured cache managers will + * Indicate whether a {@link NoOpCacheManager} should be added at the end of the delegate list. + * In this case, any {@code getCache} requests not handled by the configured CacheManagers will * be automatically handled by the {@link NoOpCacheManager} (and hence never return {@code null}). */ public void setFallbackToNoOpCache(boolean fallbackToNoOpCache) { @@ -80,11 +110,11 @@ public class CompositeCacheManager implements InitializingBean, CacheManager { @Override public Collection getCacheNames() { - List names = new ArrayList(); + Set names = new LinkedHashSet(); for (CacheManager manager : this.cacheManagers) { names.addAll(manager.getCacheNames()); } - return Collections.unmodifiableList(names); + return Collections.unmodifiableSet(names); } }