extracted majority of caching implementation to TimedCache class whic…

…h can be extended for different stores. might be good to move the store part to use composition in future

src/com/pugh/sockso/cache/ObjectCache.java

@@ -8,8 +8,12 @@
 
 import org.apache.log4j.Logger;
 
+/**
+ *  The object cache implements an in memory data store
+ * 
+ */
 @Singleton
-public class ObjectCache implements Cache {
+public class ObjectCache extends TimedCache {
 
     private static final Logger log = Logger.getLogger( ObjectCache.class );
 
@@ -27,106 +31,31 @@ public ObjectCache() {
     }
 
     /**
-     *  Indicates if the key is cached
-     *
-     *  @param key
-     *
-     *  @return
-     *
-     */
-
-    public boolean isCached( final String key ) {
-
-        final CachedObject object = readRaw( key );
-        final boolean isCached = isCacheOk( object );
-
-        log.debug( "Cache " +(isCached ? "hit" : "miss")+ " for " +key );
-
-        return isCached;
-
-    }
-
-    /**
-     *  Writes an object to the cache, will never expire
-     *
-     *  @param key
-     *
-     *  @param value
-     *
-     */
-
-    public void write( final String key, final Object value ) {
-
-        write( key, value, -1 );
-
-    }
-
-    /**
-     *  Writes an object to expire in the specified number of seconds
-     *
-     *  @param key
-     *  @param value
-     *  @param timeout
-     *
-     */
-
-    public synchronized void write( final String key, final Object value, final int timeout ) {
-
-        log.debug(
-            "Write key " +key+
-            ( timeout != -1 ? " expires in " +timeout+ " seconds" : "" )
-        );
-
-        data.put( key, new CachedObject( value, timeout ) );
-
-    }
-
-    /**
-     *  Tries to read an object from the cache, returns null on cache miss
+     *  Does a raw read on the internal data store
      *
      *  @param key
      *
      *  @return
      *
      */
-
-    public Object read( final String key ) {
-
-        final CachedObject object = readRaw( key );
 
-        return isCacheOk( object )
-            ? object.getValue()
-            : null;
-
-    }
+    protected synchronized CachedObject readRaw( final String key ) {
 
-    /**
-     *  Indicates if an internal cache object is still fresh (might be null)
-     *
-     *  @param object
-     *
-     *  @return
-     *
-     */
-
-    private boolean isCacheOk( final CachedObject object ) {
-
-        return ( object != null && !object.isExpired() );
+        return data.get( key );
 
     }
 
     /**
-     *  Does a raw read on the internal data store
-     *
+     *  Puts a cached object in the data cache
+     * 
      *  @param key
-     *
-     *  @return
-     *
+     *  @param object 
+     * 
      */
 
-    private synchronized CachedObject readRaw( final String key ) {
+    protected void writeRaw( final String key, final CachedObject object ) {
 
-        return data.get( key );
+        data.put( key, object );
 
     }
 

src/com/pugh/sockso/cache/TimedCache.java

@@ -0,0 +1,126 @@
+
+package com.pugh.sockso.cache;
+
+import org.apache.log4j.Logger;
+
+/**
+ *  Timed cached implements simple cache with optional timeout for keys.  At
+ *  the moment this is implemented through extension, but might be a good idea
+ *  at some point to refactor to use composition instead.
+ * 
+ */
+abstract public class TimedCache implements Cache {
+
+    private static final Logger log = Logger.getLogger( ObjectCache.class );
+
+    /**
+     *  Indicates if the key is cached
+     *
+     *  @param key
+     *
+     *  @return
+     *
+     */
+
+    public boolean isCached( final String key ) {
+
+        final CachedObject object = readRaw( key );
+        final boolean isCached = isCacheOk( object );
+
+        log.debug( "TimedCache " +(isCached ? "hit" : "miss")+ " for " +key );
+
+        return isCached;
+
+    }
+
+    /**
+     *  Writes an object to the cache, will never expire
+     *
+     *  @param key
+     *
+     *  @param value
+     *
+     */
+
+    public void write( final String key, final Object value ) {
+
+        write( key, value, -1 );
+
+    }
+
+    /**
+     *  Writes an object to expire in the specified number of seconds
+     *
+     *  @param key
+     *  @param value
+     *  @param timeout
+     *
+     */
+
+    public synchronized void write( final String key, final Object value, final int timeout ) {
+
+        log.debug(
+            "Write key " +key+
+            ( timeout != -1 ? " expires in " +timeout+ " seconds" : "" )
+        );
+
+        writeRaw( key, new CachedObject( value, timeout ) );
+
+    }
+
+    /**
+     *  Tries to read an object from the cache, returns null on cache miss
+     *
+     *  @param key
+     *
+     *  @return
+     *
+     */
+
+    public Object read( final String key ) {
+
+        final CachedObject object = readRaw( key );
+
+        return isCacheOk( object )
+            ? object.getValue()
+            : null;
+
+    }
+
+    /**
+     *  Indicates if an internal cache object is still fresh (might be null)
+     *
+     *  @param object
+     *
+     *  @return
+     *
+     */
+
+    private boolean isCacheOk( final CachedObject object ) {
+
+        return ( object != null && !object.isExpired() );
+
+    }
+
+    /**
+     *  Does a raw read on the internal data store, returns null on cache miss
+     *
+     *  @param key
+     *
+     *  @return
+     *
+     */
+
+    abstract protected CachedObject readRaw( final String key );
+
+    /**
+     *  Performs a raw write for a cached object
+     * 
+     *  @param key
+     *  @param object 
+     * 
+     */
+
+    abstract protected void writeRaw( final String key, final CachedObject object );
+
+}