refactor cache decorator

src/main/java/org/apache/ibatis/cache/CacheDecorator.java

@@ -0,0 +1,71 @@
+/**
+ *    Copyright 2009-2016 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.apache.ibatis.cache;
+
+import java.util.concurrent.locks.ReadWriteLock;
+
+/**
+ * abstract cache decorator.
+ * @author wuwen
+ */
+public abstract class CacheDecorator implements Cache {
+
+  private Cache delegate;
+
+  public CacheDecorator(Cache cache) {
+    this.delegate = cache;
+  }
+
+  @Override
+  public String getId() {
+    return delegate.getId();
+  }
+
+  @Override
+  public void putObject(Object key, Object value) {
+    delegate.putObject(key, value);
+  }
+
+  @Override
+  public Object getObject(Object key) {
+    return delegate.getObject(key);
+  }
+
+  @Override
+  public Object removeObject(Object key) {
+    return delegate.removeObject(key);
+  }
+
+  @Override
+  public void clear() {
+    delegate.clear();
+  }
+
+  @Override
+  public int getSize() {
+    return delegate.getSize();
+  }
+
+  @Override
+  public ReadWriteLock getReadWriteLock() {
+    return delegate.getReadWriteLock();
+  }
+
+  public Cache getDelegate() {
+    return delegate;
+  }
+
+}

src/main/java/org/apache/ibatis/cache/decorators/BlockingCache.java

@@ -1,5 +1,5 @@
 /**
- *    Copyright 2009-2015 the original author or authors.
+ *    Copyright 2009-2016 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.
@@ -18,10 +18,10 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReadWriteLock;
 import java.util.concurrent.locks.ReentrantLock;
 
 import org.apache.ibatis.cache.Cache;
+import org.apache.ibatis.cache.CacheDecorator;
 import org.apache.ibatis.cache.CacheException;
 
 /**
@@ -34,31 +34,20 @@
  * @author Eduardo Macarron
  *
  */
-public class BlockingCache implements Cache {
+public class BlockingCache extends CacheDecorator {
 
   private long timeout;
-  private final Cache delegate;
   private final ConcurrentHashMap<Object, ReentrantLock> locks;
 
   public BlockingCache(Cache delegate) {
-    this.delegate = delegate;
+    super(delegate);
     this.locks = new ConcurrentHashMap<Object, ReentrantLock>();
   }
 
-  @Override
-  public String getId() {
-    return delegate.getId();
-  }
-
-  @Override
-  public int getSize() {
-    return delegate.getSize();
-  }
-
   @Override
   public void putObject(Object key, Object value) {
     try {
-      delegate.putObject(key, value);
+      super.putObject(key, value);
     } finally {
       releaseLock(key);
     }
@@ -67,7 +56,7 @@ public void putObject(Object key, Object value) {
   @Override
   public Object getObject(Object key) {
     acquireLock(key);
-    Object value = delegate.getObject(key);
+    Object value = super.getObject(key);
     if (value != null) {
       releaseLock(key);
     }        
@@ -80,16 +69,6 @@ public Object removeObject(Object key) {
     releaseLock(key);
     return null;
   }
-
-  @Override
-  public void clear() {
-    delegate.clear();
-  }
-
-  @Override
-  public ReadWriteLock getReadWriteLock() {
-    return null;
-  }
 
   private ReentrantLock getLockForKey(Object key) {
     ReentrantLock lock = new ReentrantLock();
@@ -103,7 +82,7 @@ private void acquireLock(Object key) {
       try {
         boolean acquired = lock.tryLock(timeout, TimeUnit.MILLISECONDS);
         if (!acquired) {
-          throw new CacheException("Couldn't get a lock in " + timeout + " for the key " +  key + " at the cache " + delegate.getId());  
+          throw new CacheException("Couldn't get a lock in " + timeout + " for the key " +  key + " at the cache " + getId());
         }
       } catch (InterruptedException e) {
         throw new CacheException("Got interrupted while trying to acquire lock for key " + key, e);

src/main/java/org/apache/ibatis/cache/decorators/FifoCache.java

@@ -1,5 +1,5 @@
 /**
- *    Copyright 2009-2015 the original author or authors.
+ *    Copyright 2009-2016 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.
@@ -17,73 +17,47 @@
 
 import java.util.Deque;
 import java.util.LinkedList;
-import java.util.concurrent.locks.ReadWriteLock;
 
 import org.apache.ibatis.cache.Cache;
+import org.apache.ibatis.cache.CacheDecorator;
 
 /**
  * FIFO (first in, first out) cache decorator
  *
  * @author Clinton Begin
  */
-public class FifoCache implements Cache {
+public class FifoCache extends CacheDecorator {
 
-  private final Cache delegate;
   private Deque<Object> keyList;
   private int size;
 
   public FifoCache(Cache delegate) {
-    this.delegate = delegate;
+    super(delegate);
     this.keyList = new LinkedList<Object>();
     this.size = 1024;
   }
 
-  @Override
-  public String getId() {
-    return delegate.getId();
-  }
-
-  @Override
-  public int getSize() {
-    return delegate.getSize();
-  }
-
   public void setSize(int size) {
     this.size = size;
   }
 
   @Override
   public void putObject(Object key, Object value) {
     cycleKeyList(key);
-    delegate.putObject(key, value);
-  }
-
-  @Override
-  public Object getObject(Object key) {
-    return delegate.getObject(key);
-  }
-
-  @Override
-  public Object removeObject(Object key) {
-    return delegate.removeObject(key);
+    super.putObject(key, value);
   }
 
   @Override
   public void clear() {
-    delegate.clear();
+    super.clear();
     keyList.clear();
   }
 
-  @Override
-  public ReadWriteLock getReadWriteLock() {
-    return null;
-  }
-
   private void cycleKeyList(Object key) {
     keyList.addLast(key);
     if (keyList.size() > size) {
       Object oldestKey = keyList.removeFirst();
-      delegate.removeObject(oldestKey);
+      super.removeObject(oldestKey);
     }
   }
 

src/main/java/org/apache/ibatis/cache/decorators/LoggingCache.java

@@ -1,5 +1,5 @@
 /**
- *    Copyright 2009-2015 the original author or authors.
+ *    Copyright 2009-2016 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.
@@ -15,46 +15,30 @@
  */
 package org.apache.ibatis.cache.decorators;
 
-import java.util.concurrent.locks.ReadWriteLock;
 
 import org.apache.ibatis.cache.Cache;
+import org.apache.ibatis.cache.CacheDecorator;
 import org.apache.ibatis.logging.Log;
 import org.apache.ibatis.logging.LogFactory;
 
 /**
  * @author Clinton Begin
  */
-public class LoggingCache implements Cache {
+public class LoggingCache extends CacheDecorator {
 
   private Log log;  
-  private Cache delegate;
-  protected int requests = 0;
-  protected int hits = 0;
+  protected volatile int requests = 0;
+  protected volatile int hits = 0;
 
   public LoggingCache(Cache delegate) {
-    this.delegate = delegate;
+    super(delegate);
     this.log = LogFactory.getLog(getId());
   }
 
-  @Override
-  public String getId() {
-    return delegate.getId();
-  }
-
-  @Override
-  public int getSize() {
-    return delegate.getSize();
-  }
-
-  @Override
-  public void putObject(Object key, Object object) {
-    delegate.putObject(key, object);
-  }
-
   @Override
   public Object getObject(Object key) {
     requests++;
-    final Object value = delegate.getObject(key);
+    final Object value = super.getObject(key);
     if (value != null) {
       hits++;
     }
@@ -64,33 +48,25 @@ public Object getObject(Object key) {
     return value;
   }
 
-  @Override
-  public Object removeObject(Object key) {
-    return delegate.removeObject(key);
-  }
-
-  @Override
-  public void clear() {
-    delegate.clear();
-  }
-
-  @Override
-  public ReadWriteLock getReadWriteLock() {
-    return null;
-  }
-
   @Override
   public int hashCode() {
-    return delegate.hashCode();
+    return getDelegate().hashCode();
   }
 
   @Override
   public boolean equals(Object obj) {
-    return delegate.equals(obj);
+    return getDelegate().equals(obj);
   }
 
   private double getHitRatio() {
     return (double) hits / (double) requests;
   }
 
+  public int getRequests() {
+    return requests;
+  }
+
+  public int getHits() {
+    return hits;
+  }
 }