Add per switch TimedHashMap and minor rearrangements, not functional change

src/main/java/net/floodlightcontroller/core/IOFSwitch.java

@@ -24,6 +24,7 @@ import java.util.Map;
 import java.util.concurrent.Future;
 
 import net.floodlightcontroller.core.types.MacVlanPair;
+import net.floodlightcontroller.util.TimedHashMap;
 
 import org.jboss.netty.channel.Channel;
 import org.openflow.protocol.OFFeaturesReply;
@@ -296,4 +297,11 @@ public interface IOFSwitch {
      * Clear all flowmods on this switch
      */
     public void clearAllFlowMods();
+    
+    /**
+     * Return a TimedHashMap associated with the switch
+     * @param data
+     * @return
+     */
+    public TimedHashMap<Long> getTimedCache();
 }

src/main/java/net/floodlightcontroller/core/internal/OFSwitchImpl.java

@@ -31,6 +31,7 @@ import net.floodlightcontroller.core.FloodlightContext;
 import net.floodlightcontroller.core.IFloodlightProvider;
 import net.floodlightcontroller.core.IOFSwitch;
 import net.floodlightcontroller.core.types.MacVlanPair;
+import net.floodlightcontroller.util.TimedHashMap;
 
 import org.jboss.netty.channel.Channel;
 import org.openflow.protocol.OFFeaturesReply;
@@ -70,6 +71,7 @@ public class OFSwitchImpl implements IOFSwitch {
     protected Map<MacVlanPair,Short> macVlanToPortMap;
     protected Map<Integer,OFStatisticsFuture> statsFutureMap;
     protected boolean connected;
+    protected TimedHashMap<Long> timedCache;
     
     public static IOFSwitchFeatures switchFeatures;
     
@@ -84,6 +86,7 @@ public class OFSwitchImpl implements IOFSwitch {
         this.switchClusterId = null;
         this.connected = true;
         this.statsFutureMap = new ConcurrentHashMap<Integer,OFStatisticsFuture>();
+        this.timedCache = new TimedHashMap<Long>( 5*1000 );  // 5 seconds interval
         
         // Defaults properties for an ideal switch
         this.setAttribute(PROP_FASTWILDCARDS, (Integer) OFMatch.OFPFW_ALL);
@@ -352,4 +355,9 @@ public class OFSwitchImpl implements IOFSwitch {
             log.error("Failed to clear all flows on switch {} - {}", this, e);
         }
     }
+
+    @Override
+	public TimedHashMap<Long> getTimedCache() {
+        return timedCache;
+	}
 }

src/main/java/net/floodlightcontroller/topology/internal/TopologyImpl.java

@@ -215,6 +215,10 @@ public class TopologyImpl implements IOFMessageListener, IOFSwitchListener,
     public TopologyImpl() {
         this.lock = new ReentrantReadWriteLock();
         this.updates = new LinkedBlockingQueue<Update>();
+        this.links = new HashMap<LinkTuple, LinkInfo>();
+        this.portLinks = new HashMap<SwitchPortTuple, Set<LinkTuple>>();
+        this.switchLinks = new HashMap<IOFSwitch, Set<LinkTuple>>();
+
     }
 
     private void doUpdatesThread() throws InterruptedException {
@@ -262,9 +266,6 @@ public class TopologyImpl implements IOFMessageListener, IOFSwitchListener,
         floodlightProvider.addOFMessageListener(OFType.PACKET_IN, this);
         floodlightProvider.addOFMessageListener(OFType.PORT_STATUS, this);
         floodlightProvider.addOFSwitchListener(this);
-        links = new HashMap<LinkTuple, LinkInfo>();
-        portLinks = new HashMap<SwitchPortTuple, Set<LinkTuple>>();
-        switchLinks = new HashMap<IOFSwitch, Set<LinkTuple>>();
 
         ScheduledExecutorService ses = floodlightProvider.getScheduledExecutor();
 

src/main/java/net/floodlightcontroller/util/TimedHashMap.java

@@ -25,14 +25,15 @@ import java.util.Map;
 // The value is time-stamp in milliseconds
 // The time interval denotes the interval for which the entry should remain in the hashmap.
 
-// If an entry is present in the Linkedhashmap, it does not mean that 
+// If an entry is present in the Linkedhashmap, it does not mean that it's valid (recently seen)
 
 
-public class TimedHashMap<K, V> extends LinkedHashMap<K, V> {
+public class TimedHashMap<K> extends LinkedHashMap<K, Long> {
     
     private static final long serialVersionUID = 1L;
     
     private final long timeoutInterval;    //specified in milliseconds.
+    private long cacheHits = 0;
     
     public TimedHashMap(int ti)
     {
@@ -40,12 +41,42 @@ public class TimedHashMap<K, V> extends LinkedHashMap<K, V> {
         this.timeoutInterval = ti;
     }
     
-    protected boolean removeEldestEntry(Map.Entry<K,V> eldest) {
-       return (((Long)eldest.getValue()) < System.currentTimeMillis() - this.timeoutInterval);
+    protected boolean removeEldestEntry(Map.Entry<K, Long> eldest) {
+       return eldest.getValue() < (System.currentTimeMillis() - this.timeoutInterval);
     }
     
     public long getTimeoutInterval()
     {
         return this.timeoutInterval;
     }
+    
+    public long getCacheHits()
+    {
+    	return cacheHits;
+    }
+
+    /**
+     * Return true if key is present; otherwise add key to cache
+     * @param key
+     * @return
+     */
+    public boolean isPresent(K key)
+    {
+        Long old = this.get(key);
+        Long cur = new Long(System.currentTimeMillis());
+        
+        if (old == null) {
+        	this.put(key, cur);
+        	return false;
+        }
+
+        if (cur - old > this.timeoutInterval) {
+        	this.remove(key);   // this may be unnecessary
+            this.put(key, cur);        
+            return false;
+        }
+        
+        cacheHits++;
+        return true;
+    }
 }
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