SEC-2114: Provide Spring Cache Abstraction based cache implementations

As of Spring 3.1 spring has its own cache abstraction. This commit adds cache
imlpementations based on that abstraction.

core/src/main/java/org/springframework/security/core/userdetails/cache/SpringCacheBasedUserCache.java

@@ -0,0 +1,74 @@
+package org.springframework.security.core.userdetails.cache;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.cache.Cache;
+import org.springframework.security.core.userdetails.UserCache;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.util.Assert;
+
+/**
+ * Caches {@link UserDetails} intances in a Spring defined {@link Cache}.
+ *
+ * @author Marten Deinum
+ * @since 3.2
+ */
+public class SpringCacheBasedUserCache implements UserCache, InitializingBean {
+
+
+    //~ Static fields/initializers =====================================================================================
+
+    private static final Log logger = LogFactory.getLog(SpringCacheBasedUserCache.class);
+
+    //~ Instance fields ================================================================================================
+
+    private Cache cache;
+
+    //~ Methods ========================================================================================================
+
+    public void afterPropertiesSet() throws Exception {
+        Assert.notNull(cache, "cache mandatory");
+    }
+
+    public Cache getCache() {
+        return cache;
+    }
+
+    public UserDetails getUserFromCache(String username) {
+        Cache.ValueWrapper element = username != null ? cache.get(username) : null;
+
+        if (logger.isDebugEnabled()) {
+            logger.debug("Cache hit: " + (element != null) + "; username: " + username);
+        }
+
+        if (element == null) {
+            return null;
+        } else {
+            return (UserDetails) element.get();
+        }
+    }
+
+    public void putUserInCache(UserDetails user) {
+        if (logger.isDebugEnabled()) {
+            logger.debug("Cache put: " + user.getUsername());
+        }
+        cache.put(user.getUsername(), user);
+    }
+
+    public void removeUserFromCache(UserDetails user) {
+        if (logger.isDebugEnabled()) {
+            logger.debug("Cache remove: " + user.getUsername());
+        }
+
+        this.removeUserFromCache(user.getUsername());
+    }
+
+    public void removeUserFromCache(String username) {
+        cache.evict(username);
+    }
+
+    public void setCache(Cache cache) {
+        this.cache = cache;
+    }
+}

core/src/test/java/org/springframework/security/core/userdetails/cache/SpringCacheBasedUserCacheTests.java

@@ -0,0 +1,92 @@
+/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
+ *
+ * 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.security.core.userdetails.cache;
+
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.springframework.cache.Cache;
+import org.springframework.cache.CacheManager;
+import org.springframework.cache.concurrent.ConcurrentMapCacheManager;
+import org.springframework.security.core.authority.AuthorityUtils;
+import org.springframework.security.core.userdetails.User;
+
+import static org.junit.Assert.*;
+
+/**
+ * Tests {@link org.springframework.security.core.userdetails.cache.SpringCacheBasedUserCache}.
+ *
+ * @author Marten Deinum
+ * @since 3.2
+ *
+ */
+public class SpringCacheBasedUserCacheTests {
+    private static CacheManager cacheManager;
+
+    //~ Methods ========================================================================================================
+    @BeforeClass
+    public static void initCacheManaer() {
+        cacheManager = new ConcurrentMapCacheManager();
+        cacheManager.getCache("springbasedusercachetests");
+    }
+
+    @AfterClass
+    public static void shutdownCacheManager() {
+    }
+
+    private Cache getCache() {
+        Cache cache = cacheManager.getCache("springbasedusercachetests");
+        cache.clear();
+        return cache;
+    }
+
+    private User getUser() {
+        return new User("john", "password", true, true, true, true,
+                AuthorityUtils.createAuthorityList("ROLE_ONE", "ROLE_TWO"));
+    }
+
+    @Test
+    public void cacheOperationsAreSuccessful() throws Exception {
+        SpringCacheBasedUserCache cache = new SpringCacheBasedUserCache();
+        cache.setCache(getCache());
+        cache.afterPropertiesSet();
+
+        // Check it gets stored in the cache
+        cache.putUserInCache(getUser());
+        assertEquals(getUser().getPassword(), cache.getUserFromCache(getUser().getUsername()).getPassword());
+
+        // Check it gets removed from the cache
+        cache.removeUserFromCache(getUser());
+        assertNull(cache.getUserFromCache(getUser().getUsername()));
+
+        // Check it doesn't return values for null or unknown users
+        assertNull(cache.getUserFromCache(null));
+        assertNull(cache.getUserFromCache("UNKNOWN_USER"));
+    }
+
+    @Test(expected = IllegalArgumentException.class)
+    public void startupDetectsMissingCache() throws Exception {
+        SpringCacheBasedUserCache cache = new SpringCacheBasedUserCache();
+
+        cache.afterPropertiesSet();
+        fail("Should have thrown IllegalArgumentException");
+
+        Cache myCache = getCache();
+        cache.setCache(myCache);
+        assertEquals(myCache, cache.getCache());
+    }
+}