refactor cache decorator

Author: wuwen5

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

@@ -0,0 +1,72 @@
+/*
+ *    Copyright 2009-2023 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
+ *
+ *       https://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 final 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

@@ -20,6 +20,7 @@
 import java.util.concurrent.TimeUnit;
 
 import org.apache.ibatis.cache.Cache;
+import org.apache.ibatis.cache.CacheDecorator;
 import org.apache.ibatis.cache.CacheException;
 
 /**
@@ -34,31 +35,20 @@
  *
  * @author Eduardo Macarron
  */
-public class BlockingCache implements Cache {
+public class BlockingCache extends CacheDecorator {
 
   private long timeout;
-  private final Cache delegate;
   private final ConcurrentHashMap<Object, CountDownLatch> locks;
 
   public BlockingCache(Cache delegate) {
-    this.delegate = delegate;
+    super(delegate);
     this.locks = new ConcurrentHashMap<>();
   }
 
-  @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 +57,7 @@ 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);
     }
@@ -81,11 +71,6 @@ public Object removeObject(Object key) {
     return null;
   }
 
-  @Override
-  public void clear() {
-    delegate.clear();
-  }
-
   private void acquireLock(Object key) {
     CountDownLatch newLatch = new CountDownLatch(1);
     while (true) {
@@ -98,7 +83,7 @@ private void acquireLock(Object key) {
           boolean acquired = latch.await(timeout, TimeUnit.MILLISECONDS);
           if (!acquired) {
             throw new CacheException(
-                "Couldn't get a lock in " + timeout + " for the key " + key + " at the cache " + delegate.getId());
+                "Couldn't get a lock in " + timeout + " for the key " + key + " at the cache " + super.getId());
           }
         } else {
           latch.await();

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

@@ -19,66 +19,56 @@
 import java.util.LinkedList;
 
 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 final Deque<Object> keyList;
   private int size;
 
   public FifoCache(Cache delegate) {
-    this.delegate = delegate;
+    super(delegate);
     this.keyList = new LinkedList<>();
     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);
+    super.putObject(key, value);
   }
 
   @Override
   public Object getObject(Object key) {
-    return delegate.getObject(key);
+    return super.getObject(key);
   }
 
   @Override
   public Object removeObject(Object key) {
     keyList.remove(key);
-    return delegate.removeObject(key);
+    return super.removeObject(key);
   }
 
   @Override
   public void clear() {
-    delegate.clear();
+    super.clear();
     keyList.clear();
   }
 
   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

@@ -16,43 +16,28 @@
 package org.apache.ibatis.cache.decorators;
 
 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 final Log log;
-  private final Cache delegate;
   protected int requests;
   protected int hits;
 
   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++;
     }
@@ -62,28 +47,21 @@ 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 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 getHits() {
+    return hits;
+  }
 }

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

@@ -19,33 +19,23 @@
 import java.util.Map;
 
 import org.apache.ibatis.cache.Cache;
+import org.apache.ibatis.cache.CacheDecorator;
 
 /**
  * Lru (least recently used) cache decorator.
  *
  * @author Clinton Begin
  */
-public class LruCache implements Cache {
+public class LruCache extends CacheDecorator {
 
-  private final Cache delegate;
   private Map<Object, Object> keyMap;
   private Object eldestKey;
 
   public LruCache(Cache delegate) {
-    this.delegate = delegate;
+    super(delegate);
     setSize(1024);
   }
 
-  @Override
-  public String getId() {
-    return delegate.getId();
-  }
-
-  @Override
-  public int getSize() {
-    return delegate.getSize();
-  }
-
   public void setSize(final int size) {
     keyMap = new LinkedHashMap<Object, Object>(size, .75F, true) {
       private static final long serialVersionUID = 4267176411845948333L;
@@ -63,32 +53,32 @@ protected boolean removeEldestEntry(Map.Entry<Object, Object> eldest) {
 
   @Override
   public void putObject(Object key, Object value) {
-    delegate.putObject(key, value);
+    super.putObject(key, value);
     cycleKeyList(key);
   }
 
   @Override
   public Object getObject(Object key) {
     keyMap.get(key); // touch
-    return delegate.getObject(key);
+    return super.getObject(key);
   }
 
   @Override
   public Object removeObject(Object key) {
     keyMap.remove(key);
-    return delegate.removeObject(key);
+    return super.removeObject(key);
   }
 
   @Override
   public void clear() {
-    delegate.clear();
+    super.clear();
     keyMap.clear();
   }
 
   private void cycleKeyList(Object key) {
     keyMap.put(key, key);
     if (eldestKey != null) {
-      delegate.removeObject(eldestKey);
+      super.removeObject(eldestKey);
       eldestKey = null;
     }
   }