DATAREDIS-344 - Assert RedisCache works with Spring 4.1.

Added `putIfAbsent` to `RedisCache` to satisfy compatibility with newly introduced method. Original pull request: spring-projects#102.

Author: christophstrobl

src/main/java/org/springframework/data/redis/cache/RedisCache.java

@@ -137,6 +137,38 @@ public Object doInRedis(RedisConnection connection) throws DataAccessException {
 }, true);
 }
 
+public ValueWrapper putIfAbsent(Object key, final Object value) {
+
+final byte[] keyBytes = computeKey(key);
+final byte[] valueBytes = convertToBytesIfNecessary(template.getValueSerializer(), value);
+
+return toWrapper(template.execute(new RedisCallback<Object>() {
+public Object doInRedis(RedisConnection connection) throws DataAccessException {
+
+waitForLock(connection);
+
+Object resultValue = value;
+boolean valueWasSet = connection.setNX(keyBytes, valueBytes);
+if (valueWasSet) {
+connection.zAdd(setName, 0, keyBytes);
+if (expiration > 0) {
+connection.expire(keyBytes, expiration);
+// update the expiration of the set of keys as well
+connection.expire(setName, expiration);
+}
+} else {
+resultValue = deserializeIfNecessary(template.getValueSerializer(), connection.get(keyBytes));
+}
+
+return resultValue;
+}
+}, true));
+}
+
+private ValueWrapper toWrapper(Object value) {
+return (value != null ? new SimpleValueWrapper(value) : null);
+}
+
 public void evict(Object key) {
 final byte[] k = computeKey(key);
 
@@ -227,4 +259,14 @@ private byte[] convertToBytesIfNecessary(RedisSerializer<Object> serializer, Obj
 
 return serializer.serialize(value);
 }
+
+private Object deserializeIfNecessary(RedisSerializer<byte[]> serializer, byte[] value) {
+
+if (serializer != null) {
+return serializer.deserialize(value);
+}
+
+return value;
+}
+
 }

src/test/java/org/springframework/data/redis/cache/RedisCacheTest.java

@@ -16,14 +16,17 @@
 
 package org.springframework.data.redis.cache;
 
-import static org.hamcrest.core.IsInstanceOf.*;
-import static org.hamcrest.core.IsNull.*;
+import static org.hamcrest.core.IsEqual.equalTo;
+import static org.hamcrest.core.IsInstanceOf.instanceOf;
+import static org.hamcrest.core.IsNot.not;
+import static org.hamcrest.core.IsNull.nullValue;
+import static org.hamcrest.core.IsSame.sameInstance;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.assertTrue;
-import static org.junit.Assume.*;
+import static org.junit.Assume.assumeThat;
 import static org.springframework.data.redis.matcher.RedisTestMatchers.isEqual;
 
 import java.util.Collection;
@@ -71,7 +74,7 @@ public static Collection<Object[]> testParams() {
 }
 
 @SuppressWarnings("unchecked")
-protected Cache createCache(RedisTemplate nativeCache) {
+protected RedisCache createCache(RedisTemplate nativeCache) {
 return new RedisCache(CACHE_NAME, CACHE_NAME.concat(":").getBytes(), nativeCache, TimeUnit.MINUTES.toSeconds(10));
 }
 
@@ -246,4 +249,31 @@ public void testCacheGetShouldReturnNullIfNoCachedValueFound() {
 Object invalidKey = template.getKeySerializer() == null ? "spring-data-redis".getBytes() : "spring-data-redis";
 assertThat(redisCache.get(invalidKey, value.getClass()), nullValue());
 }
+
+/**
+ * @see DATAREDIS-344
+ */
+@Test
+public void putIfAbsentShouldSetValueOnlyIfNotPresent() {
+
+assumeThat(cache, instanceOf(RedisCache.class));
+
+RedisCache redisCache = (RedisCache)cache;
+
+Object key = getKey();
+template.delete(key);
+
+Object value = getValue();
+ValueWrapper wrapper = redisCache.putIfAbsent(key, value);
+
+assertThat(wrapper.get(), sameInstance(value));
+
+ValueWrapper wrapper2 = redisCache.putIfAbsent(key, value);
+
+if (!(value instanceof Number)) {
+assertThat(wrapper2.get(), not(sameInstance(value)));
+}
+
+assertThat(wrapper2.get(), equalTo(value));
+}
 }