Merge pull request #985 from sulake/feature/map_cache_max_size

Add support for bounded Redisson map cache (max size configuration).

redisson/src/main/java/org/redisson/api/MapOptions.java

@@ -49,6 +49,7 @@ public class MapOptions<K, V> {
     private MapWriter<K, V> writer;
     private WriteMode writeMode = WriteMode.WRITE_THROUGH;
     private int writeBehindThreads = 1;
+    private int maxSize = 0;
     
     protected MapOptions() {
     }
@@ -135,4 +136,19 @@ public class MapOptions<K, V> {
         return loader;
     }
 
+    /**
+     * Sets max size of the map.
+     * <p>
+     * Currently only RedissonMapCache is supported.
+     *
+     * @param maxSize - max size
+     * @return MapOptions instance
+     */
+    public MapOptions<K, V> maxSize(int maxSize) {
+        this.maxSize = maxSize;
+        return this;
+    }
+    public int getMaxSize() {
+        return maxSize;
+    }
 }

redisson/src/test/java/org/redisson/RedissonMapCacheTest.java

@@ -214,6 +214,31 @@ public class RedissonMapCacheTest extends BaseMapTest {
         assertThat(store).isEqualTo(expected);
     }
 
+    @Test
+    public void testFastPutMaxSize() {
+        final int maxSize = 2;
+        Map<String, String> store = new LinkedHashMap<String, String>() {
+            @Override
+            protected boolean removeEldestEntry(Entry<String, String> eldest) {
+                return size() > maxSize;
+            }
+        };
+        MapOptions<String, String> options = MapOptions.<String, String>defaults().writer(createMapWriter(store));
+        options.maxSize(maxSize);
+        RMapCache<String, String> map = redisson.getMapCache("test", options);
+
+        map.fastPut("1", "11", 10, TimeUnit.SECONDS);
+        map.fastPut("2", "22", 10, TimeUnit.SECONDS);
+        map.fastPut("3", "33", 10, TimeUnit.SECONDS);
+
+        assertThat(map.size()).isEqualTo(maxSize);
+
+        Map<String, String> expected = new HashMap<>();
+        expected.put("2", "22");
+        expected.put("3", "33");
+        assertThat(store).isEqualTo(expected);
+    }
+    
     @Test
     public void testOrdering() {
         Map<String, String> map = new LinkedHashMap<String, String>();