Cleanups: Collections.singleton(), COWAS - includes ticket #388

apps/i2ptunnel/java/src/net/i2p/i2ptunnel/I2PTunnel.java

@@ -43,13 +43,13 @@ import java.io.OutputStream;
 import java.net.InetAddress;
 import java.net.UnknownHostException;
 import java.util.ArrayList;
-import java.util.HashSet;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Properties;
 import java.util.Set;
 import java.util.StringTokenizer;
+import java.util.concurrent.CopyOnWriteArraySet;
 
 import net.i2p.I2PAppContext;
 import net.i2p.I2PException;
@@ -99,7 +99,7 @@ public class I2PTunnel implements Logging, EventDispatcher {
     private final List tasks = new ArrayList();
     private int next_task_id = 1;
 
-    private final Set listeners = new HashSet();
+    private final Set listeners = new CopyOnWriteArraySet();
 
     public static void main(String[] args) throws IOException {
         new I2PTunnel(args);
@@ -1626,16 +1626,12 @@ public class I2PTunnel implements Logging, EventDispatcher {
 
     public void addConnectionEventListener(ConnectionEventListener lsnr) {
         if (lsnr == null) return;
-        synchronized (listeners) {
+        listeners.add(lsnr);
-            listeners.add(lsnr);
-        }
     }
 
     public void removeConnectionEventListener(ConnectionEventListener lsnr) {
         if (lsnr == null) return;
-        synchronized (listeners) {
+        listeners.remove(lsnr);
-            listeners.remove(lsnr);
-        }
     }
     
     private String getPrefix() { return "[" + _tunnelId + "]: "; }
@@ -1649,12 +1645,10 @@ public class I2PTunnel implements Logging, EventDispatcher {
      */
     void routerDisconnected() {
         _log.error(getPrefix() + "Router disconnected - firing notification events");
-        synchronized (listeners) {
             for (Iterator iter = listeners.iterator(); iter.hasNext();) {
                 ConnectionEventListener lsnr = (ConnectionEventListener) iter.next();
                 if (lsnr != null) lsnr.routerDisconnected();
             }
-        }
     }
 
     /**

apps/i2ptunnel/java/src/net/i2p/i2ptunnel/TunnelControllerGroup.java

@@ -310,7 +310,7 @@ public class TunnelControllerGroup {
         synchronized (_sessions) {
             Set<TunnelController> owners = _sessions.get(session);
             if (owners == null) {
-                owners = new HashSet(1);
+                owners = new HashSet(2);
                 _sessions.put(session, owners);
             }
             owners.add(controller);

apps/streaming/java/src/net/i2p/client/streaming/MessageHandler.java

@@ -2,13 +2,13 @@ package net.i2p.client.streaming;
 
 import java.util.Iterator;
 import java.util.Set;
+import java.util.concurrent.CopyOnWriteArraySet;
 
 import net.i2p.I2PAppContext;
 import net.i2p.client.I2PSession;
 import net.i2p.client.I2PSessionException;
 import net.i2p.client.I2PSessionListener;
 import net.i2p.util.Log;
-import net.i2p.util.ConcurrentHashSet;
 
 /**
  * Receive raw information from the I2PSession and turn it into
@@ -24,7 +24,7 @@ class MessageHandler implements I2PSessionListener {
     public MessageHandler(I2PAppContext ctx, ConnectionManager mgr) {
         _manager = mgr;
         _context = ctx;
-        _listeners = new ConcurrentHashSet(1);
+        _listeners = new CopyOnWriteArraySet();
         _log = ctx.logManager().getLog(MessageHandler.class);
         _context.statManager().createRateStat("stream.packetReceiveFailure", "When do we fail to decrypt or otherwise receive a packet sent to us?", "Stream", new long[] { 60*60*1000, 24*60*60*1000 });
     }

core/java/src/net/i2p/crypto/ElGamalAESEngine.java

@@ -10,6 +10,7 @@ package net.i2p.crypto;
  */
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
@@ -527,8 +528,6 @@ public class ElGamalAESEngine {
         return aesEncr;
     }
 
-    private final static Set EMPTY_SET = new HashSet();
-
     /**
      * For both scenarios, this method encrypts the AES area using the given key, iv
      * and making sure the resulting data is at least as long as the paddedSize and 
@@ -552,7 +551,7 @@ public class ElGamalAESEngine {
                                         long paddedSize, int prefixBytes) {
         //_log.debug("iv for encryption: " + DataHelper.toString(iv, 16));
         //_log.debug("Encrypting AES");
-        if (tagsForDelivery == null) tagsForDelivery = EMPTY_SET;
+        if (tagsForDelivery == null) tagsForDelivery = Collections.EMPTY_SET;
         int size = 2 // sizeof(tags)
                  + tagsForDelivery.size()
                  + SessionTag.BYTE_LENGTH*tagsForDelivery.size()

core/java/src/net/i2p/util/Clock.java

@@ -1,8 +1,8 @@
 package net.i2p.util;
 
-import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Set;
+import java.util.concurrent.CopyOnWriteArraySet;
 
 import net.i2p.I2PAppContext;
 import net.i2p.time.Timestamper;
@@ -19,19 +19,19 @@ import net.i2p.time.Timestamper;
  *
  */
 public class Clock implements Timestamper.UpdateListener {
-    protected I2PAppContext _context;
+    protected final I2PAppContext _context;
-    private Timestamper _timestamper;
+    private final Timestamper _timestamper;
-    protected long _startedOn;
+    protected final long _startedOn;
     protected boolean _statCreated;
+    protected volatile long _offset;
+    protected boolean _alreadyChanged;
+    private final Set _listeners;
     
     public Clock(I2PAppContext context) {
         _context = context;
-        _offset = 0;
+        _listeners = new CopyOnWriteArraySet();
-        _alreadyChanged = false;
-        _listeners = new HashSet(1);
         _timestamper = new Timestamper(context, this);
         _startedOn = System.currentTimeMillis();
-        _statCreated = false;
     }
     public static Clock getInstance() {
         return I2PAppContext.getGlobalContext().clock();
@@ -41,10 +41,6 @@ public class Clock implements Timestamper.UpdateListener {
     
     /** we fetch it on demand to avoid circular dependencies (logging uses the clock) */
     protected Log getLog() { return _context.logManager().getLog(Clock.class); }
-    
-    protected volatile long _offset;
-    protected boolean _alreadyChanged;
-    private final Set _listeners;
 
     /** if the clock is skewed by 3+ days, fuck 'em */
     public final static long MAX_OFFSET = 3 * 24 * 60 * 60 * 1000;
@@ -136,24 +132,18 @@ public class Clock implements Timestamper.UpdateListener {
     }
 
     public void addUpdateListener(ClockUpdateListener lsnr) {
-        synchronized (_listeners) {
             _listeners.add(lsnr);
-        }
     }
 
     public void removeUpdateListener(ClockUpdateListener lsnr) {
-        synchronized (_listeners) {
             _listeners.remove(lsnr);
-        }
     }
 
     protected void fireOffsetChanged(long delta) {
-        synchronized (_listeners) {
             for (Iterator iter = _listeners.iterator(); iter.hasNext();) {
                 ClockUpdateListener lsnr = (ClockUpdateListener) iter.next();
                 lsnr.offsetChanged(delta);
             }
-        }
     }
 
     public static interface ClockUpdateListener {

core/java/src/net/i2p/util/I2PAppThread.java

@@ -10,9 +10,9 @@ package net.i2p.util;
  */
 
 
-import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Set;
+import java.util.concurrent.CopyOnWriteArraySet;
 
 /**
  * Like I2PThread but with per-thread OOM listeners,
@@ -22,7 +22,7 @@ import java.util.Set;
  */
 public class I2PAppThread extends I2PThread {
 
-    private Set _threadListeners = new HashSet(0);
+    private final Set _threadListeners = new CopyOnWriteArraySet();
 
     public I2PAppThread() {
         super();

core/java/src/net/i2p/util/I2PThread.java

@@ -10,9 +10,9 @@ package net.i2p.util;
  */
 
 
-import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Set;
+import java.util.concurrent.CopyOnWriteArraySet;
 
 /**
  * In case its useful later...
@@ -21,7 +21,7 @@ import java.util.Set;
  */
 public class I2PThread extends Thread {
     private static volatile Log _log;
-    private static Set _listeners = new HashSet(4);
+    private static final Set _listeners = new CopyOnWriteArraySet();
     private String _name;
     private Exception _createdBy;
 

router/java/src/net/i2p/router/OutNetMessage.java

@@ -225,7 +225,7 @@ public class OutNetMessage {
     
     public void transportFailed(String transportStyle) { 
         if (_failedTransports == null)
-            _failedTransports = new HashSet(1);
+            _failedTransports = new HashSet(2);
         _failedTransports.add(transportStyle); 
     }
     /** not thread safe - dont fail transports and iterate over this at the same time */

router/java/src/net/i2p/router/RouterClock.java

@@ -34,7 +34,7 @@ public class RouterClock extends Clock {
     private long _lastChanged;
     private int _lastStratum;
 
-    RouterContext _contextRC; // LINT field hides another field
+    private final RouterContext _contextRC;
 
     public RouterClock(RouterContext context) {
         super(context);

router/java/src/net/i2p/router/Shitlist.java

@@ -156,7 +156,7 @@ public class Shitlist {
         e.causeCode = reasonCode;
         e.transports = null;
         if (transport != null) {
-            e.transports = new ConcurrentHashSet(1);
+            e.transports = new ConcurrentHashSet(2);
             e.transports.add(transport);
         }
         

router/java/src/net/i2p/router/networkdb/kademlia/FloodfillPeerSelector.java

@@ -74,8 +74,9 @@ class FloodfillPeerSelector extends PeerSelector {
      */
     List<Hash> selectNearestExplicitThin(Hash key, int maxNumRouters, Set<Hash> peersToIgnore, KBucketSet kbuckets, boolean preferConnected) { 
         if (peersToIgnore == null)
-            peersToIgnore = new HashSet(1);
+            peersToIgnore = Collections.singleton(_context.routerHash());
-        peersToIgnore.add(_context.routerHash());
+        else
+            peersToIgnore.add(_context.routerHash());
         // TODO this is very slow
         FloodfillSelectionCollector matches = new FloodfillSelectionCollector(key, peersToIgnore, maxNumRouters);
         if (kbuckets == null) return new ArrayList();
@@ -94,8 +95,7 @@ class FloodfillPeerSelector extends PeerSelector {
      *  List is not sorted and not shuffled.
      */
     List<Hash> selectFloodfillParticipants(KBucketSet kbuckets) {
-        Set<Hash> ignore = new HashSet(1);
+        Set<Hash> ignore = Collections.singleton(_context.routerHash());
-        ignore.add(_context.routerHash());
         return selectFloodfillParticipants(ignore, kbuckets);
     }
 
@@ -132,8 +132,7 @@ class FloodfillPeerSelector extends PeerSelector {
      *  Group 3: All others
      */
     List<Hash> selectFloodfillParticipants(Hash key, int maxNumRouters, KBucketSet kbuckets) {
-        Set<Hash> ignore = new HashSet(1);
+        Set<Hash> ignore = Collections.singleton(_context.routerHash());
-        ignore.add(_context.routerHash());
         return selectFloodfillParticipants(key, maxNumRouters, ignore, kbuckets);
     }
 
@@ -152,8 +151,7 @@ class FloodfillPeerSelector extends PeerSelector {
      */
     List<Hash> selectFloodfillParticipants(Hash key, int howMany, Set<Hash> toIgnore, KBucketSet kbuckets) {
         if (toIgnore == null) {
-            toIgnore = new HashSet(1);
+            toIgnore = Collections.singleton(_context.routerHash());
-            toIgnore.add(_context.routerHash());
         } else if (!toIgnore.contains(_context.routerHash())) {
             // copy the Set so we don't confuse StoreJob
             toIgnore = new HashSet(toIgnore);

router/java/src/net/i2p/router/networkdb/kademlia/PeerSelector.java

@@ -31,8 +31,8 @@ import net.i2p.util.Log;
  *  Mostly unused, see overrides in FloodfillPeerSelector
  */
 class PeerSelector {
-    protected Log _log;
+    protected final Log _log;
-    protected RouterContext _context;
+    protected final RouterContext _context;
     
     public PeerSelector(RouterContext ctx) {
         _context = ctx;

router/java/src/net/i2p/router/networkdb/kademlia/SearchJob.java

@@ -9,7 +9,7 @@ package net.i2p.router.networkdb.kademlia;
  */
 
 import java.util.ArrayList;
-import java.util.HashSet;
+import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
@@ -800,8 +800,7 @@ class SearchJob extends JobImpl {
         if (rv) {
             if (_log.shouldLog(Log.DEBUG))
                 _log.debug(getJobId() + ": Queueing up for next time: " + peer);
-            Set s = new HashSet(1);
+            Set<Hash> s = Collections.singleton(peer);
-            s.add(peer);
             _facade.queueForExploration(s);
         }
         return rv;

router/java/src/net/i2p/router/peermanager/PeerManager.java

@@ -11,6 +11,7 @@ package net.i2p.router.peermanager;
 import java.io.IOException;
 import java.io.Writer;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
@@ -115,8 +116,7 @@ class PeerManager {
      */
     List<Hash> selectPeers(PeerSelectionCriteria criteria) {
         Set<Hash> peers = new HashSet(criteria.getMinimumRequired());
-        Set<Hash> exclude = new HashSet(1);
+        Set<Hash> exclude = Collections.singleton(_context.routerHash());
-        exclude.add(_context.routerHash());
         switch (criteria.getPurpose()) {
             case PeerSelectionCriteria.PURPOSE_TEST:
                 // for now, the peers we test will be the reliable ones

router/java/src/net/i2p/router/tunnel/pool/TestJob.java

@@ -1,6 +1,6 @@
 package net.i2p.router.tunnel.pool;
 
-import java.util.HashSet;
+import java.util.Collections;
 import java.util.Set;
 
 import net.i2p.crypto.SessionKeyManager;
@@ -144,8 +144,7 @@ class TestJob extends JobImpl {
             scheduleRetest();
             return;
         }
-        Set encryptTags = new HashSet(1);
+        Set<SessionTag> encryptTags = Collections.singleton(encryptTag);
-        encryptTags.add(encryptTag);
         // Register the single tag with the appropriate SKM
         if (_cfg.isInbound() && !_pool.getSettings().isExploratory()) {
             SessionKeyManager skm = getContext().clientManager().getClientSessionKeyManager(_pool.getSettings().getDestination());