Move NoOpCache to a top-level public class

This commit moves `NoOpCache` to a top-level public class to allow reuse
in custom CacheManager arrangement.

Issue: SPR-14856

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

@@ -0,0 +1,92 @@
+/*
+ * Copyright 2002-2016 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.support;
+
+import java.util.concurrent.Callable;
+
+import org.springframework.cache.Cache;
+
+/**
+ * A no operation {@link Cache} implementation suitable
+ * for disabling caching.
+ *
+ * <p>Will simply accept any items into the cache not actually storing them.
+ *
+ * @author Costin Leau
+ * @author Stephane Nicoll
+ * @since 4.3.4
+ */
+public class NoOpCache implements Cache {
+
+	private final String name;
+
+	/**
+	 * Create a {@link NoOpCache} instance with the specified name
+	 * @param name the name of the cache
+	 */
+	public NoOpCache(String name) {
+		this.name = name;
+	}
+
+	@Override
+	public void clear() {
+	}
+
+	@Override
+	public void evict(Object key) {
+	}
+
+	@Override
+	public ValueWrapper get(Object key) {
+		return null;
+	}
+
+	@Override
+	public <T> T get(Object key, Class<T> type) {
+		return null;
+	}
+
+	@Override
+	public <T> T get(Object key, Callable<T> valueLoader) {
+		try {
+			return valueLoader.call();
+		}
+		catch (Exception ex) {
+			throw new ValueRetrievalException(key, valueLoader, ex);
+		}
+	}
+
+	@Override
+	public String getName() {
+		return this.name;
+	}
+
+	@Override
+	public Object getNativeCache() {
+		return null;
+	}
+
+	@Override
+	public void put(Object key, Object value) {
+	}
+
+	@Override
+	public ValueWrapper putIfAbsent(Object key, Object value) {
+		return null;
+	}
+
+}

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

@@ -20,7 +20,6 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.Set;
-import java.util.concurrent.Callable;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 
@@ -73,61 +72,4 @@ public class NoOpCacheManager implements CacheManager {
 		}
 	}
 
-
-	private static class NoOpCache implements Cache {
-
-		private final String name;
-
-		public NoOpCache(String name) {
-			this.name = name;
-		}
-
-		@Override
-		public void clear() {
-		}
-
-		@Override
-		public void evict(Object key) {
-		}
-
-		@Override
-		public ValueWrapper get(Object key) {
-			return null;
-		}
-
-		@Override
-		public <T> T get(Object key, Class<T> type) {
-			return null;
-		}
-
-		@Override
-		public <T> T get(Object key, Callable<T> valueLoader) {
-			try {
-				return valueLoader.call();
-			}
-			catch (Exception ex) {
-				throw new ValueRetrievalException(key, valueLoader, ex);
-			}
-		}
-
-		@Override
-		public String getName() {
-			return this.name;
-		}
-
-		@Override
-		public Object getNativeCache() {
-			return null;
-		}
-
-		@Override
-		public void put(Object key, Object value) {
-		}
-
-		@Override
-		public ValueWrapper putIfAbsent(Object key, Object value) {
-			return null;
-		}
-	}
-
 }