Provide predetermined capacity for cache operation collections

Issue: SPR-17079

(cherry picked from commit 20c34cb)

Author: jhoeller

spring-context/src/main/java/org/springframework/cache/interceptor/AbstractCacheResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -32,6 +32,7 @@
  * invocation context.
  *
  * @author Stephane Nicoll
+ * @author Juergen Hoeller
  * @since 4.1
  */
 public abstract class AbstractCacheResolver implements CacheResolver, InitializingBean {
@@ -40,9 +41,17 @@ public abstract class AbstractCacheResolver implements CacheResolver, Initializi
 	private CacheManager cacheManager;
 
 
+	/**
+	 * Construct a new {@code AbstractCacheResolver}.
+	 * @see #setCacheManager
+	 */
 	protected AbstractCacheResolver() {
 	}
 
+	/**
+	 * Construct a new {@code AbstractCacheResolver} for the given {@link CacheManager}.
+	 * @param cacheManager the CacheManager to use
+	 */
 	protected AbstractCacheResolver(CacheManager cacheManager) {
 		this.cacheManager = cacheManager;
 	}
@@ -75,18 +84,16 @@ public Collection<? extends Cache> resolveCaches(CacheOperationInvocationContext
 		if (cacheNames == null) {
 			return Collections.emptyList();
 		}
-		else {
-			Collection<Cache> result = new ArrayList<>();
-			for (String cacheName : cacheNames) {
-				Cache cache = getCacheManager().getCache(cacheName);
-				if (cache == null) {
-					throw new IllegalArgumentException("Cannot find cache named '" +
-							cacheName + "' for " + context.getOperation());
-				}
-				result.add(cache);
+		Collection<Cache> result = new ArrayList<>(cacheNames.size());
+		for (String cacheName : cacheNames) {
+			Cache cache = getCacheManager().getCache(cacheName);
+			if (cache == null) {
+				throw new IllegalArgumentException("Cannot find cache named '" +
+						cacheName + "' for " + context.getOperation());
 			}
-			return result;
+			result.add(cache);
 		}
+		return result;
 	}
 
 	/**

spring-context/src/main/java/org/springframework/cache/interceptor/CacheAspectSupport.java

@@ -557,16 +557,16 @@ private Object generateKey(CacheOperationContext context, @Nullable Object resul
 
 	private class CacheOperationContexts {
 
-		private final MultiValueMap<Class<? extends CacheOperation>, CacheOperationContext> contexts =
-				new LinkedMultiValueMap<>();
+		private final MultiValueMap<Class<? extends CacheOperation>, CacheOperationContext> contexts;
 
 		private final boolean sync;
 
 		public CacheOperationContexts(Collection<? extends CacheOperation> operations, Method method,
 				Object[] args, Object target, Class<?> targetClass) {
 
-			for (CacheOperation operation : operations) {
-				this.contexts.add(operation.getClass(), getOperationContext(operation, method, args, target, targetClass));
+			this.contexts = new LinkedMultiValueMap<>(operations.size());
+			for (CacheOperation op : operations) {
+				this.contexts.add(op.getClass(), getOperationContext(op, method, args, target, targetClass));
 			}
 			this.sync = determineSyncFlag(method);
 		}
@@ -594,18 +594,22 @@ private boolean determineSyncFlag(Method method) {
 			}
 			if (syncEnabled) {
 				if (this.contexts.size() > 1) {
-					throw new IllegalStateException("@Cacheable(sync=true) cannot be combined with other cache operations on '" + method + "'");
+					throw new IllegalStateException(
+							"@Cacheable(sync=true) cannot be combined with other cache operations on '" + method + "'");
 				}
 				if (cacheOperationContexts.size() > 1) {
-					throw new IllegalStateException("Only one @Cacheable(sync=true) entry is allowed on '" + method + "'");
+					throw new IllegalStateException(
+							"Only one @Cacheable(sync=true) entry is allowed on '" + method + "'");
 				}
 				CacheOperationContext cacheOperationContext = cacheOperationContexts.iterator().next();
 				CacheableOperation operation = (CacheableOperation) cacheOperationContext.getOperation();
 				if (cacheOperationContext.getCaches().size() > 1) {
-					throw new IllegalStateException("@Cacheable(sync=true) only allows a single cache on '" + operation + "'");
+					throw new IllegalStateException(
+							"@Cacheable(sync=true) only allows a single cache on '" + operation + "'");
 				}
 				if (StringUtils.hasText(operation.getUnless())) {
-					throw new IllegalStateException("@Cacheable(sync=true) does not support unless attribute on '" + operation + "'");
+					throw new IllegalStateException(
+							"@Cacheable(sync=true) does not support unless attribute on '" + operation + "'");
 				}
 				return true;
 			}