Merge pull request #178 from DSheirer/165-overflowable-buffer-issue-causes-channels-decoding-stop

165 overflowable buffer issue causes channels decoding stop

.idea/dictionaries/denny.xml

@@ -7,6 +7,7 @@
       <w>fleetsync</w>
       <w>icecast</w>
       <w>ident</w>
+      <w>overflowable</w>
       <w>polyphase</w>
       <w>remez</w>
       <w>samplerate</w>

CHANGELOG

@@ -1,10 +1,10 @@
 
 0.3.0-beta1 20170129
+ - REQUIRES: Java 8 (or newer) for compatibility and eventual changeover to JavaFX
  - FEATURE: audio streaming - adds capability to stream to multiple remote broadcast
    servers (Broadcastify, Icecast v2.3 and v2.4+, and Shoutcast V1 and V2).  Each
    stream can be independently configured with a delay.  Audio calls are directed
    to one or more streams by attaching one or more stream identifiers to each alias.
- - Requires Java 8 (or newer) for compatibility and eventual changeover to JavaFX
  - Extensive GUI updates for tuner, channel and alias management.  Includes new
    'Now Playing' channel view and 'Detail' view.
  - Updated alias list management of alias id values and wildcards.  Weighting is now
@@ -17,7 +17,7 @@
  - Implemented bounded queues for both tuner and individual channel IQ sample
    buffers.  Bounded queues have ability to enter/exit overflow state when queue
    size reaches overflow threshold and reset when queue size falls below the reset
-   threshold.
+   threshold.  Channel state will show OVERFLOW in red/yellow.
  - Updated airspy controller for airspy-mini specific sample rate handling.
  - New developer remez filter designer tool and internal usage
 

src/alias/PatchGroupAlias.java

@@ -168,11 +168,14 @@ public class PatchGroupAlias extends Alias
 
         for(Alias alias: mPatchedAliases)
         {
-            for(AliasAction action: alias.getAction())
+            if(!(alias instanceof PatchGroupAlias))
             {
-                if(!aliasActions.contains(action))
+                for(AliasAction action: alias.getAction())
                 {
-                    aliasActions.add(action);
+                    if(!aliasActions.contains(action))
+                    {
+                        aliasActions.add(action);
+                    }
                 }
             }
         }
@@ -185,7 +188,7 @@ public class PatchGroupAlias extends Alias
     {
         for(Alias alias: mPatchedAliases)
         {
-            if(alias.hasActions())
+            if(!(alias instanceof PatchGroupAlias) && alias.hasActions())
             {
                 return true;
             }
@@ -201,7 +204,9 @@ public class PatchGroupAlias extends Alias
 
         for(Alias alias: mPatchedAliases)
         {
-            if(alias.hasCallPriority() && alias.getCallPriority() < highestPriority)
+            if(!(alias instanceof PatchGroupAlias) &&
+                alias.hasCallPriority() &&
+                alias.getCallPriority() < highestPriority)
             {
                 highestPriority = alias.getCallPriority();
             }
@@ -220,7 +225,7 @@ public class PatchGroupAlias extends Alias
 
         for(Alias alias: mPatchedAliases)
         {
-            if(alias.hasCallPriority())
+            if(!(alias instanceof PatchGroupAlias) && alias.hasCallPriority())
             {
                 return true;
             }
@@ -239,7 +244,7 @@ public class PatchGroupAlias extends Alias
 
         for(Alias alias: mPatchedAliases)
         {
-            if(alias.isRecordable())
+            if(!(alias instanceof PatchGroupAlias) && alias.isRecordable())
             {
                 return true;
             }
@@ -258,7 +263,7 @@ public class PatchGroupAlias extends Alias
 
         for(Alias alias: mPatchedAliases)
         {
-            if(alias.isStreamable())
+            if(!(alias instanceof PatchGroupAlias) && alias.isStreamable())
             {
                 return true;
             }
@@ -279,11 +284,14 @@ public class PatchGroupAlias extends Alias
 
         for(Alias alias: mPatchedAliases)
         {
-            for(BroadcastChannel broadcastChannel: alias.getBroadcastChannels())
+            if(!(alias instanceof PatchGroupAlias))
             {
-                if(!broadcastChannels.contains(broadcastChannel))
+                for(BroadcastChannel broadcastChannel: alias.getBroadcastChannels())
                 {
-                    broadcastChannels.add(broadcastChannel);
+                    if(!broadcastChannels.contains(broadcastChannel))
+                    {
+                        broadcastChannels.add(broadcastChannel);
+                    }
                 }
             }
         }
@@ -301,7 +309,7 @@ public class PatchGroupAlias extends Alias
 
         for(Alias alias: mPatchedAliases)
         {
-            if(alias.hasBroadcastChannel(channel))
+            if(!(alias instanceof PatchGroupAlias) && alias.hasBroadcastChannel(channel))
             {
                 return true;
             }

src/channel/metadata/ChannelMetadataPanel.java

@@ -210,6 +210,10 @@ public class ChannelMetadataPanel extends JPanel implements ListSelectionListene
                         background = SystemProperties.getInstance().get(PROPERTY_PREFIX_BACKGROUND + "idle", Color.WHITE);
                         foreground = SystemProperties.getInstance().get(PROPERTY_PREFIX_FOREGROUND + "idle", Color.BLUE);
                         break;
+                    case OVERFLOW:
+                        background = SystemProperties.getInstance().get(PROPERTY_PREFIX_BACKGROUND + "overflow", Color.RED);
+                        foreground = SystemProperties.getInstance().get(PROPERTY_PREFIX_FOREGROUND + "overflow", Color.YELLOW);
+                        break;
                     case RESET:
                         background = SystemProperties.getInstance().get(PROPERTY_PREFIX_BACKGROUND + "reset", Color.PINK);
                         foreground = SystemProperties.getInstance().get(PROPERTY_PREFIX_FOREGROUND + "reset", Color.YELLOW);

src/channel/metadata/ChannelMetadataViewer.java

@@ -51,7 +51,7 @@ public class ChannelMetadataViewer extends JPanel
         mChannelDetailPanel = new ChannelDetailPanel(channelProcessingManager);
         mCallEventPanel = new CallEventPanel(iconManager);
         mMessageActivityPanel = new MessageActivityPanel(channelProcessingManager);
-        mChannelSpectrumPanel = new ChannelSpectrumPanel(settingsManager, channelProcessingManager);
+//        mChannelSpectrumPanel = new ChannelSpectrumPanel(settingsManager, channelProcessingManager);
         mChannelMetadataPanel = new ChannelMetadataPanel(channelProcessingManager, iconManager);
 
         init();

src/channel/state/ChannelState.java

@@ -35,6 +35,7 @@ import module.decode.event.ICallEventProvider;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import sample.Listener;
+import sample.real.IOverflowListener;
 
 import java.util.concurrent.RejectedExecutionException;
 import java.util.concurrent.ScheduledExecutorService;
@@ -42,7 +43,7 @@ import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 
 public class ChannelState extends Module implements ICallEventProvider, IDecoderStateEventListener,
-    IDecoderStateEventProvider, ISquelchStateProvider, IAttributeChangeRequestListener
+    IDecoderStateEventProvider, ISquelchStateProvider, IAttributeChangeRequestListener, IOverflowListener
 {
     private final static Logger mLog = LoggerFactory.getLogger(ChannelState.class);
 
@@ -63,6 +64,7 @@ public class ChannelState extends Module implements ICallEventProvider, IDecoder
 
     private boolean mSquelchLocked = false;
     private boolean mSelected = false;
+    private boolean mSourceOverflow = false;
 
     private long mStandardChannelFadeTimeout = FADE_TIMEOUT_DELAY;
     private long mTrafficChannelFadeTimeout = DecodeConfiguration.DEFAULT_CALL_TIMEOUT_SECONDS * 1000;
@@ -123,6 +125,7 @@ public class ChannelState extends Module implements ICallEventProvider, IDecoder
 
         mState = State.IDLE;
         mMutableMetadata.receive(new AttributeChangeRequest<State>(Attribute.CHANNEL_STATE, mState));
+        mSourceOverflow = false;
     }
 
     @Override
@@ -350,15 +353,26 @@ public class ChannelState extends Module implements ICallEventProvider, IDecoder
                         break;
                 }
 
-                mMutableMetadata.receive(new AttributeChangeRequest<State>(Attribute.CHANNEL_STATE, mState));
+                mMutableMetadata.receive(new AttributeChangeRequest<State>(Attribute.CHANNEL_STATE,
-            }
+                    mSourceOverflow ? State.OVERFLOW : mState));
-            else
-            {
-//				mLog.debug( "Can't change from [" + mState + "] to [" + state + "]" );
             }
         }
     }
 
+    /**
+     * This method is invoked if the source buffer provider goes into overflow state.  Since this is an external state,
+     * we use the mSourceOverflow variable to override the internal state reported to external listeners.
+     * @param overflow true to indicate an overflow state
+     */
+    @Override
+    public void sourceOverflow(boolean overflow)
+    {
+        mSourceOverflow = overflow;
+
+        mMutableMetadata.receive(new AttributeChangeRequest<State>(Attribute.CHANNEL_STATE,
+            mSourceOverflow ? State.OVERFLOW : mState));
+    }
+
     /**
      * Sets the state and processes related actions
      */

src/channel/state/DecoderState.java

@@ -51,6 +51,14 @@ public abstract class DecoderState extends Module implements ActivitySummaryProv
         return mAliasList != null;
     }
 
+    /**
+     * Provides subclass reference to the call event broadcaster
+     */
+    protected Broadcaster<CallEvent> getCallEventBroadcaster()
+    {
+        return mCallEventBroadcaster;
+    }
+
     /**
      * Reset the decoder state to prepare for processing a different sample
      * source

src/channel/state/State.java

@@ -24,97 +24,93 @@ import java.util.EnumSet;
  */
 public enum State
 {
-	IDLE( "IDLE" ) 
+    IDLE("IDLE")
-	{
-        @Override
-        public boolean canChangeTo( State state )
         {
-	        return state != TEARDOWN && 
+            @Override
-	        	   state != RESET;
+            public boolean canChangeTo(State state)
-        }
+            {
-    }, 
+                return state != TEARDOWN && state != RESET && state != OVERFLOW;
-	CALL( "CALL" ) 
+            }
-	{
+        },
-        @Override
+    CALL("CALL")
-        public boolean canChangeTo( State state )
         {
-	        return state == CONTROL ||
+            @Override
-	        	   state == DATA ||
+            public boolean canChangeTo(State state)
-	        	   state == ENCRYPTED ||
+            {
-	        	   state == FADE ||
+                return state == CONTROL || state == DATA || state == ENCRYPTED || state == FADE || state == TEARDOWN;
-	        	   state == TEARDOWN;
+            }
-        }
+        },
-    }, 
+    DATA("DATA")
-	DATA( "DATA" ) 
-	{
-        @Override
-        public boolean canChangeTo( State state )
         {
-	        return state == CALL ||
+            @Override
-	        	   state == CONTROL ||
+            public boolean canChangeTo(State state)
-		           state == ENCRYPTED ||
+            {
-		           state == FADE ||
+                return state == CALL || state == CONTROL || state == ENCRYPTED || state == FADE || state == TEARDOWN;
-		           state == TEARDOWN;
+            }
-        }
+        },
-    },
+    ENCRYPTED("ENCRYPTED")
-    ENCRYPTED( "ENCRYPTED" )
+        {
+            @Override
+            public boolean canChangeTo(State state)
+            {
+                return state == FADE || state == TEARDOWN;
+            }
+        },
+    CONTROL("CONTROL")
+        {
+            @Override
+            public boolean canChangeTo(State state)
+            {
+                return state == IDLE || state == FADE;
+            }
+        },
+    FADE("FADE")
+        {
+            @Override
+            public boolean canChangeTo(State state)
+            {
+                return state != FADE && state != RESET && state != OVERFLOW;
+            }
+        },
+    OVERFLOW("OVERFLOW")
+        {
+            @Override
+            public boolean canChangeTo(State state)
+            {
+                return false;
+            }
+        },
+    RESET("RESET")
+        {
+            @Override
+            public boolean canChangeTo(State state)
+            {
+                return state == IDLE;
+            }
+        },
+    TEARDOWN("TEARDOWN")
+        {
+            @Override
+            public boolean canChangeTo(State state)
+            {
+                return state == RESET;
+            }
+        };
+
+    private String mDisplayValue;
+
+    public static final EnumSet<State> CALL_STATES = EnumSet.of(CALL, CONTROL, DATA, ENCRYPTED);
+    public static final EnumSet<State> IDLE_STATES = EnumSet.of(IDLE, FADE);
+
+    private State(String displayValue)
     {
-        @Override
+        mDisplayValue = displayValue;
-        public boolean canChangeTo( State state )
+    }
-        {
+
-        	return state == FADE || state == TEARDOWN;
+    public abstract boolean canChangeTo(State state);
-        }
+
-    },
+    public String getDisplayValue()
-    CONTROL( "CONTROL" )
     {
-		@Override
+        return mDisplayValue;
-        public boolean canChangeTo( State state )
+    }
-        {
-            return state == IDLE || 
-            	   state == FADE;
-        }
-    },
-	FADE( "FADE" ) 
-	{
-        @Override
-        public boolean canChangeTo( State state )
-        {
-	        return state != FADE && 
-	        	   state != RESET; 
-	    }
-    },
-	RESET( "RESET" ) 
-	{
-		@Override
-		public boolean canChangeTo(State state)
-		{
-			return state == IDLE;
-		}
-	},
-	
-	TEARDOWN( "TEARDOWN" ) 
-	{
-		@Override
-		public boolean canChangeTo(State state) 
-		{
-			return state == RESET;
-		}
-	};
-	
-	private String mDisplayValue;
-	
-	public static final EnumSet<State> CALL_STATES = EnumSet.of( CALL, CONTROL, DATA, ENCRYPTED );
-	public static final EnumSet<State> IDLE_STATES = EnumSet.of( IDLE, FADE );
-	
-	private State( String displayValue )
-	{
-		mDisplayValue = displayValue;
-	}
-	
-	public abstract boolean canChangeTo( State state );
-	
-	public String getDisplayValue()
-	{
-		return mDisplayValue;
-	}
 }

src/controller/NamingThreadFactory.java

@@ -1,5 +1,9 @@
 package controller;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import util.ThreadPool;
+
 import java.util.concurrent.ThreadFactory;
 import java.util.concurrent.atomic.AtomicInteger;
 
@@ -8,24 +12,23 @@ import java.util.concurrent.atomic.AtomicInteger;
  */
 public class NamingThreadFactory implements ThreadFactory 
 {
-    static final AtomicInteger poolNumber = new AtomicInteger(1);
+    private final static Logger mLog = LoggerFactory.getLogger(ThreadPool.class);
 
-    final ThreadGroup mThreadGroup;
+    private static final AtomicInteger mPoolNumber = new AtomicInteger(1);
     
-    final AtomicInteger mThreadNumber = new AtomicInteger(1);
+    private final ThreadGroup mThreadGroup;
     
-    final String mNamePrefix;
+    private final AtomicInteger mThreadNumber = new AtomicInteger(1);
+    
+    private final String mNamePrefix;
 
     public NamingThreadFactory( String prefix ) 
     {
     	SecurityManager s = System.getSecurityManager();
         
-        mThreadGroup = (s != null)? s.getThreadGroup() :
+        mThreadGroup = (s != null)? s.getThreadGroup() : Thread.currentThread().getThreadGroup();
-                             Thread.currentThread().getThreadGroup();
         
-        mNamePrefix = prefix + " pool-" +
+        mNamePrefix = prefix + " pool-" + mPoolNumber.getAndIncrement() + "-thread-";
-                      poolNumber.getAndIncrement() +
-                     "-thread-";
     }
 
     public Thread newThread( Runnable runnable ) 
@@ -43,6 +46,15 @@ public class NamingThreadFactory implements ThreadFactory
             thread.setPriority( Thread.NORM_PRIORITY );
         }
 
+        thread.setUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler()
+        {
+            @Override
+            public void uncaughtException(Thread t, Throwable e)
+            {
+                mLog.error("Error while executing runnable in scheduled thread pool [" + t.getName() + "]", e);
+            }
+        });
+
         return thread;
     }
 }

src/module/ProcessingChain.java

@@ -538,6 +538,9 @@ public class ProcessingChain implements IChannelEventListener
                     module.reset();
                 }
 
+                //Setup the channel state to monitor source overflow conditions
+                mSource.setOverflowListener(mChannelState);
+
 				/* Register with the source to receive sample data.  Setup a 
 				 * timer task to process the buffer queues 50 times a second 
 				 * (every 20 ms) */
@@ -606,6 +609,7 @@ public class ProcessingChain implements IChannelEventListener
             if(mSource != null)
             {
                 mSource.stop();
+                mSource.setOverflowListener(null);
 
                 switch(mSource.getSampleType())
                 {

src/module/decode/p25/P25DecoderState.java

@@ -19,9 +19,7 @@ package module.decode.p25;
 
 import alias.Alias;
 import alias.AliasList;
-import alias.PatchGroupAlias;
 import alias.id.AliasIDType;
-import alias.id.talkgroup.TalkgroupID;
 import channel.metadata.AliasedStringAttributeMonitor;
 import channel.metadata.Attribute;
 import channel.metadata.AttributeChangeRequest;
@@ -163,7 +161,6 @@ public class P25DecoderState extends DecoderState
     private Map<Integer,IdentifierUpdate> mBands = new HashMap<>();
     private Map<String,Long> mRegistrations = new HashMap<>();
     private Map<String,IAdjacentSite> mNeighborMap = new HashMap<>();
-    private Map<String,List<String>> mPatchGroupMap = new HashMap<>();
 
     private String mLastCommandEventID;
     private String mLastPageEventID;
@@ -188,6 +185,7 @@ public class P25DecoderState extends DecoderState
     private P25CallEvent mCurrentCallEvent;
     private List<String> mCallDetectTalkgroups = new ArrayList<>();
     private Map<String,P25CallEvent> mChannelCallMap = new HashMap<>();
+    private PatchGroupManager mPatchGroupManager;
 
     public P25DecoderState(AliasList aliasList,
                            ChannelType channelType,
@@ -199,6 +197,7 @@ public class P25DecoderState extends DecoderState
         mModulation = modulation;
         mIgnoreDataCalls = ignoreDataCalls;
 
+        mPatchGroupManager = new PatchGroupManager(aliasList, getCallEventBroadcaster());
         mSiteAttributeMonitor = new AliasedStringAttributeMonitor(Attribute.NETWORK_ID_2,
             getAttributeChangeRequestListener(), getAliasList(), AliasIDType.SITE);
         mFromTalkgroupMonitor = new AliasedStringAttributeMonitor(Attribute.PRIMARY_ADDRESS_FROM,
@@ -2719,6 +2718,9 @@ public class P25DecoderState extends DecoderState
         switch(((MotorolaTSBKMessage)tsbk).getMotorolaOpcode())
         {
             case PATCH_GROUP_CHANNEL_GRANT:
+                //Cleanup patch groups - auto-expire any patch groups before we allocate a channel
+                mPatchGroupManager.cleanupPatchGroups();
+
                 PatchGroupVoiceChannelGrant pgvcg = (PatchGroupVoiceChannelGrant)tsbk;
 
                 channel = pgvcg.getChannel();
@@ -2754,6 +2756,9 @@ public class P25DecoderState extends DecoderState
                     mChannelCallMap.get(channel)));
                 break;
             case PATCH_GROUP_CHANNEL_GRANT_UPDATE:
+                //Cleanup patch groups - auto-expire any patch groups before we allocate a channel
+                mPatchGroupManager.cleanupPatchGroups();
+
                 PatchGroupVoiceChannelGrantUpdate gvcgu = (PatchGroupVoiceChannelGrantUpdate)tsbk;
 
                 channel = gvcgu.getChannel1();
@@ -2784,35 +2789,11 @@ public class P25DecoderState extends DecoderState
                 break;
             case PATCH_GROUP_ADD:
                 PatchGroupAdd pga = (PatchGroupAdd)tsbk;
-
+                mPatchGroupManager.updatePatchGroup(pga.getPatchGroupAddress(), pga.getPatchedTalkgroups());
-                if(addPatchGroup(pga.getPatchGroupAddress(), pga.getPatchedTalkgroups()))
-                {
-                    StringBuilder sb = new StringBuilder();
-
-                    sb.append("PATCH GROUP:").append(pga.getPatchGroupAddress());
-                    sb.append(" ").append(pga.getPatchedTalkgroups());
-
-                    broadcast(new P25CallEvent.Builder(CallEventType.PATCH_GROUP_ADD)
-                        .aliasList(getAliasList())
-                        .details(sb.toString())
-                        .build());
-                }
                 break;
             case PATCH_GROUP_DELETE:
                 PatchGroupDelete pgd = (PatchGroupDelete)tsbk;
-
+                mPatchGroupManager.removePatchGroup(pgd.getPatchGroupAddress());
-                if(removePatchGroup(pgd.getPatchGroupAddress(), pgd.getPatchedTalkgroups()))
-                {
-                    StringBuilder sbpgd = new StringBuilder();
-
-                    sbpgd.append("PATCH GROUP:").append(pgd.getPatchGroupAddress());
-                    sbpgd.append(" ").append(pgd.getPatchedTalkgroups());
-
-                    broadcast(new P25CallEvent.Builder(CallEventType.PATCH_GROUP_DELETE)
-                        .aliasList(getAliasList())
-                        .details(sbpgd.toString())
-                        .build());
-                }
                 break;
             case CCH_PLANNED_SHUTDOWN:
                 if(!mControlChannelShutdownLogged)
@@ -2827,174 +2808,14 @@ public class P25DecoderState extends DecoderState
         }
     }
 
-    /**
-     * Creates a new patch group or updates an existing patch group with the patched talkgroup entries.
-     *
-     * @param patchGroupID for the patch group
-     * @param talkgroupsToAdd to include in the patch group
-     * @return true if the patch group or the patch group map was updated
-     */
-    private boolean addPatchGroup(String patchGroupID, List<String> talkgroupsToAdd)
-    {
-        boolean updated = false;
-
-        if(patchGroupID != null && !talkgroupsToAdd.isEmpty())
-        {
-            List<String> patchedTalkgroups = mPatchGroupMap.get(patchGroupID);
-
-            if(patchedTalkgroups == null)
-            {
-                patchedTalkgroups = new ArrayList<>();
-            }
-
-            for(String talkgroupToAdd : talkgroupsToAdd)
-            {
-                //Exclude the patch group ID if it is included in the patched talkgroup list so that we don't have
-                //an infinite loop situation
-                if(talkgroupToAdd.equals(patchGroupID))
-                {
-                    continue;
-                }
-
-                if(!patchedTalkgroups.contains(talkgroupToAdd))
-                {
-                    patchedTalkgroups.add(talkgroupToAdd);
-                    updated = true;
-                }
-            }
-
-            if(updated)
-            {
-                mPatchGroupMap.put(patchGroupID, patchedTalkgroups);
-                updatePatchAlias(patchGroupID, patchedTalkgroups);
-            }
-        }
-
-        return updated;
-    }
-
-    /**
-     * Removes the patched talkgroups from the patch group and removes the patch group from the patch group map if
-     * there are no more patched talkgroups in the patch group.
-     *
-     * @param patchGroupID for the patch group
-     * @param talkgroupsToRemove to remove from the patch group
-     * @return true if the patch group or the patch group map was updated
-     */
-    private boolean removePatchGroup(String patchGroupID, List<String> talkgroupsToRemove)
-    {
-        boolean updated = false;
-
-        if(patchGroupID != null && !talkgroupsToRemove.isEmpty())
-        {
-            List<String> patchedTalkgroups = mPatchGroupMap.get(patchGroupID);
-
-            if(patchedTalkgroups != null)
-            {
-                for(String talkgroupToRemove : talkgroupsToRemove)
-                {
-                    if(patchedTalkgroups.contains(talkgroupToRemove))
-                    {
-                        patchedTalkgroups.remove(talkgroupToRemove);
-                        updated = true;
-                    }
-                }
-
-                if(patchedTalkgroups.isEmpty())
-                {
-                    mPatchGroupMap.remove(patchGroupID);
-                    removePatchGroupAlias(patchGroupID);
-                    updated = true;
-                }
-                else
-                {
-                    updatePatchAlias(patchGroupID, patchedTalkgroups);
-                }
-            }
-        }
-
-        return updated;
-    }
-
-    /**
-     * Adds/updates a patch group alias to the alias list containing aliases for each of the patched talkgroups.  If the
-     * patch group alias already exists, any patched talkgroups will be removed from the existing patch group alias and
-     * replaced with the aliases corresponding to the patched talkgroup aliases.
-     *
-     * @param patchGroupID for the patch group
-     * @param patchedTalkgroups containing the talkgroup IDs for each of the patched talkgroups
-     */
-    private void updatePatchAlias(String patchGroupID, List<String> patchedTalkgroups)
-    {
-        PatchGroupAlias patchGroupAlias = null;
-
-        //Check for an existing alias for the patch talkgroup - do not include wildcard aliases
-        Alias existingAlias = getAliasList().getTalkgroupAlias(patchGroupID, false);
-
-        if(existingAlias instanceof PatchGroupAlias)
-        {
-            patchGroupAlias = (PatchGroupAlias)existingAlias;
-        }
-        else
-        {
-            patchGroupAlias = new PatchGroupAlias();
-
-            patchGroupAlias.addAliasID(new TalkgroupID(patchGroupID));
-
-            if(existingAlias != null)
-            {
-                getAliasList().removeAlias(existingAlias);
-
-                patchGroupAlias.setPatchGroupAlias(existingAlias);
-            }
-
-            getAliasList().addAlias(patchGroupAlias);
-        }
-
-        if(patchGroupAlias != null)
-        {
-            patchGroupAlias.setPatchedTalkgroupIDs(patchedTalkgroups);
-
-            patchGroupAlias.clearPatchedAliases();
-
-            for(String patchedTalkgroup : patchedTalkgroups)
-            {
-                Alias patchedAlias = getAliasList().getTalkgroupAlias(patchedTalkgroup);
-
-                if(patchedAlias != null)
-                {
-                    patchGroupAlias.addPatchedAlias(patchedAlias);
-                }
-            }
-        }
-    }
-
-    /**
-     * Removes the temporary patch group alias from the alias list
-     */
-    private void removePatchGroupAlias(String patchGroupID)
-    {
-        Alias alias = getAliasList().getTalkgroupAlias(patchGroupID);
-
-        if(alias instanceof PatchGroupAlias)
-        {
-            PatchGroupAlias patchGroupAlias = (PatchGroupAlias)alias;
-
-            getAliasList().removeAlias(patchGroupAlias);
-
-            //Replace our temporary patch group alias with the original alias for the patch group ID
-            if(patchGroupAlias.hasPatchGroupAlias())
-            {
-                getAliasList().addAlias(patchGroupAlias.getPatchGroupAlias());
-            }
-        }
-    }
-
     /**
      * Process a traffic channel allocation message
      */
     private void processTSBKChannelGrant(TSBKMessage message)
     {
+        //Cleanup patch groups - auto-expire any patch groups before we allocate a channel
+        mPatchGroupManager.cleanupPatchGroups();
+
         String channel = null;
         String from = null;
         String to = null;

src/module/decode/p25/PatchGroup.java

@@ -0,0 +1,102 @@
+/*******************************************************************************
+ * sdrtrunk
+ * Copyright (C) 2014-2017 Dennis Sheirer
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ ******************************************************************************/
+package module.decode.p25;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class PatchGroup
+{
+    private long mExpireThreshold = 5000; //5 seconds
+    private long mLastUpdated;
+    private String mPatchGroupID;
+    private List<String> mPatchedGroups = new ArrayList<>();
+
+    /**
+     * Constructs a patch group with the specified patch group ID
+     * @param patchGroupID that identifies this patch group
+     */
+    public PatchGroup(String patchGroupID)
+    {
+        mPatchGroupID = patchGroupID;
+        mLastUpdated = System.currentTimeMillis();
+    }
+
+    /**
+     * Patch group ID for this patch group
+     */
+    public String getPatchGroupID()
+    {
+        return mPatchGroupID;
+    }
+
+    /**
+     * Adds the patched group to this patch group.  Duplicate patched groups are ignored.
+     *
+     * Note: the patch group ID will not be added as a patched group, to avoid circular dependencies.
+     *
+     * @return true if the patched group was added to this patch group
+     */
+    public boolean addPatchedGroup(String patchedGroup)
+    {
+        if(patchedGroup != null && !patchedGroup.equals(mPatchGroupID) && !mPatchedGroups.contains(patchedGroup))
+        {
+            mPatchedGroups.add(patchedGroup);
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Patched talkgroups that are part of this patch group.
+     */
+    public List<String> getPatchedGroups()
+    {
+        return mPatchedGroups;
+    }
+
+    /**
+     * Updates the timestamp for this patch group.
+     */
+    public void updateTimestamp()
+    {
+        mLastUpdated = System.currentTimeMillis();
+    }
+
+    /**
+     * Indicates if this patch group is expired, meaning that it hasn't been updated in the past (expire
+     * threshold) seconds.
+     */
+    public boolean isExpired()
+    {
+        return System.currentTimeMillis() - mLastUpdated > mExpireThreshold;
+    }
+
+    /**
+     * Sets the patch group expiration threshold (default = 5000 ms).  A patch group is considered expired if
+     * no new updates have been received within the past (expire threshold) milliseconds
+     *
+     * @param expireThreshold in milliseconds
+     */
+    public void setExpireThreshold(long expireThreshold)
+    {
+        mExpireThreshold = expireThreshold;
+    }
+}

src/module/decode/p25/PatchGroupManager.java

@@ -0,0 +1,245 @@
+/*******************************************************************************
+ * sdrtrunk
+ * Copyright (C) 2014-2017 Dennis Sheirer
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ ******************************************************************************/
+package module.decode.p25;
+
+import alias.Alias;
+import alias.AliasList;
+import alias.PatchGroupAlias;
+import alias.id.talkgroup.TalkgroupID;
+import module.decode.event.CallEvent;
+import sample.Broadcaster;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+public class PatchGroupManager
+{
+    private AliasList mAliasList;
+    private List<PatchGroup> mPatchGroups = new ArrayList<>();
+    private Broadcaster<CallEvent> mCallEventBroadcaster;
+
+    /**
+     * Manages active P25 patch groups and auto-expires patch groups if not updated every 5 seconds.
+     *
+     * @param aliasList to keep updated with patch group changes
+     * @param broadcaster for rebroadcasting patch group related call events
+     */
+    public PatchGroupManager(AliasList aliasList, Broadcaster<CallEvent> broadcaster)
+    {
+        mAliasList = aliasList;
+        mCallEventBroadcaster = broadcaster;
+    }
+
+    /**
+     * Removes the patch group.
+     *
+     * @param patchGroupID of the patch group to remove
+     */
+    public void removePatchGroup(String patchGroupID)
+    {
+        removePatchGroup(patchGroupID, false);
+    }
+
+    /**
+     * Removes the patch group.
+     *
+     * @param patchGroupID of the patch group to remove
+     * @param expired true if the patch group is being removed because it expired, false if we receive a
+     * message commanding commanding a patch group delete.
+     */
+    private void removePatchGroup(String patchGroupID, boolean expired)
+    {
+        PatchGroup patchGroup = getPatchGroup(patchGroupID);
+
+        if(patchGroup != null)
+        {
+            //Cleanup the alias list
+            if(mAliasList != null)
+            {
+                Alias alias = mAliasList.getTalkgroupAlias(patchGroupID);
+
+                if(alias instanceof PatchGroupAlias)
+                {
+                    PatchGroupAlias patchGroupAlias = (PatchGroupAlias)alias;
+
+                    mAliasList.removeAlias(patchGroupAlias);
+
+                    //Replace our temporary patch group alias with the original alias for the patch group ID
+                    if(patchGroupAlias.hasPatchGroupAlias())
+                    {
+                        mAliasList.addAlias(patchGroupAlias.getPatchGroupAlias());
+                    }
+                }
+            }
+
+            mPatchGroups.remove(patchGroup);
+
+            if(mCallEventBroadcaster != null)
+            {
+                StringBuilder sb = new StringBuilder();
+
+                sb.append((expired ? "EXPIRED " : "DELETED "));
+                sb.append("PATCH GROUP:").append(patchGroup.getPatchGroupID());
+                sb.append(" ").append(patchGroup.getPatchedGroups());
+
+
+                mCallEventBroadcaster.broadcast(new P25CallEvent.Builder(CallEvent.CallEventType.PATCH_GROUP_DELETE)
+                    .to(patchGroup.getPatchGroupID())
+                    .details(sb.toString())
+                    .build());
+            }
+        }
+    }
+
+    /**
+     * Adds/updates a patch group alias to the alias list containing aliases for each of the patched talkgroups.  If the
+     * patch group alias already exists, any patched talkgroups will be removed from the existing patch group alias and
+     * replaced with the aliases corresponding to the patched talkgroup aliases.
+     *
+     * @param patchGroupID for the patch group
+     * @param patchedTalkgroups containing the talkgroup IDs for each of the patched talkgroups
+     */
+    public void updatePatchGroup(String patchGroupID, List<String> patchedTalkgroups)
+    {
+        boolean updated = false;
+
+        PatchGroup patchGroup = getPatchGroup(patchGroupID);
+
+        if(patchGroup == null)
+        {
+            //Remove any expired patch groups before we add a new one
+            cleanupPatchGroups();
+            patchGroup = new PatchGroup(patchGroupID);
+            mPatchGroups.add(patchGroup);
+            updated = true;
+        }
+        else
+        {
+            patchGroup.updateTimestamp();
+        }
+
+        for(String patchedGroup : patchedTalkgroups)
+        {
+            if(patchGroup.addPatchedGroup(patchedGroup))
+            {
+                updated = true;
+            }
+        }
+
+        //If we make any changes to the patch group, update the patch group alias
+        if(updated)
+        {
+            PatchGroupAlias patchGroupAlias = null;
+
+            //Check for an existing alias for the patch talkgroup - do not include wildcard aliases
+            if(mAliasList != null)
+            {
+                Alias existingAlias = mAliasList.getTalkgroupAlias(patchGroupID, false);
+
+                if(existingAlias instanceof PatchGroupAlias)
+                {
+                    patchGroupAlias = (PatchGroupAlias)existingAlias;
+                }
+                else
+                {
+                    patchGroupAlias = new PatchGroupAlias();
+
+                    patchGroupAlias.addAliasID(new TalkgroupID(patchGroupID));
+
+                    if(existingAlias != null)
+                    {
+                        mAliasList.removeAlias(existingAlias);
+
+                        patchGroupAlias.setPatchGroupAlias(existingAlias);
+                    }
+
+                    mAliasList.addAlias(patchGroupAlias);
+                }
+
+                if(patchGroupAlias != null)
+                {
+                    patchGroupAlias.setPatchedTalkgroupIDs(patchGroup.getPatchedGroups());
+
+                    patchGroupAlias.clearPatchedAliases();
+
+                    for(String patchedTalkgroup : patchGroup.getPatchedGroups())
+                    {
+                        Alias patchedAlias = mAliasList.getTalkgroupAlias(patchedTalkgroup);
+
+                        if(patchedAlias != null)
+                        {
+                            patchGroupAlias.addPatchedAlias(patchedAlias);
+                        }
+                    }
+                }
+            }
+
+            if(mCallEventBroadcaster != null)
+            {
+                StringBuilder sb = new StringBuilder();
+
+                sb.append("PATCH GROUP:").append(patchGroup.getPatchGroupID());
+                sb.append(" ").append(patchGroup.getPatchedGroups());
+
+                mCallEventBroadcaster.broadcast(new P25CallEvent.Builder(CallEvent.CallEventType.PATCH_GROUP_ADD)
+                    .aliasList(mAliasList)
+                    .details(sb.toString())
+                    .build());
+            }
+        }
+    }
+
+    /**
+     * Returns the patch group matching the patch group ID or null
+     */
+    private PatchGroup getPatchGroup(String patchGroupID)
+    {
+        for(PatchGroup patchGroup : mPatchGroups)
+        {
+            if(patchGroup.getPatchGroupID().equals(patchGroupID))
+            {
+                return patchGroup;
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * Checks the last updated timestamp on all patch groups and removes any patch groups that have not been
+     * updated in the past 5 seconds
+     */
+    public void cleanupPatchGroups()
+    {
+        Iterator<PatchGroup> it = mPatchGroups.iterator();
+
+        while(it.hasNext())
+        {
+            PatchGroup patchGroup = it.next();
+
+            if(patchGroup.isExpired())
+            {
+                it.remove();
+
+                removePatchGroup(patchGroup.getPatchGroupID(), true);
+            }
+        }
+    }
+}

src/sample/OverflowableTransferQueue.java

@@ -18,20 +18,28 @@
  ******************************************************************************/
 package sample;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import sample.real.IOverflowListener;
+import source.tuner.TunerChannelSource;
+
 import java.util.Collection;
 import java.util.concurrent.LinkedTransferQueue;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 
 public class OverflowableTransferQueue<E>
 {
+    private final static Logger mLog = LoggerFactory.getLogger(OverflowableTransferQueue.class);
+
     public enum State {NORMAL, OVERFLOW};
-    private Listener<State> mStateListener;
+    private IOverflowListener mOverflowListener;
 
     private LinkedTransferQueue<E> mQueue = new LinkedTransferQueue<E>();
     private AtomicInteger mCounter = new AtomicInteger();
+    private AtomicBoolean mOverflow = new AtomicBoolean();
     private int mMaximumSize;
     private int mResetThreshold;
-    private boolean mOverflow = false;
 
     /**
      * Concurrent transfer queue that couples a higher-throughput linked transfer queue with an atomic integer for
@@ -53,7 +61,7 @@ public class OverflowableTransferQueue<E>
      */
     public void offer(E e)
     {
-        if(!mOverflow)
+        if(!mOverflow.get())
         {
             mQueue.offer(e);
 
@@ -73,46 +81,36 @@ public class OverflowableTransferQueue<E>
     {
         int drainCount = mQueue.drainTo(collection, maxElements);
 
-        if(drainCount > 0)
+        int size = mCounter.addAndGet(-drainCount);
-        {
-            int size = mCounter.addAndGet(-drainCount);
 
-            if(mOverflow && size <= mResetThreshold)
+        if(mOverflow.get() && size <= mResetThreshold)
-            {
+        {
-                setOverflow(false);
+            setOverflow(false);
-            }
         }
 
         return drainCount;
     }
 
     /**
-     * Sets a listener to receive state change events
+     * Sets a listener to receive overflow state change events
      */
-    public void setStateListener(Listener<State> listener)
+    public void setOverflowListener(IOverflowListener listener)
     {
-        mStateListener = listener;
+        mOverflowListener = listener;
     }
 
 
     /**
-     * Current state of the queue, normal or overflow
+     * Toggles the overflow state and broadcast state change to listener
-     */
-    public State getState()
-    {
-        return mOverflow ? State.OVERFLOW : State.NORMAL;
-    }
-
-    /**
-     * Toggles the overflow state
      */
     private void setOverflow(boolean overflow)
     {
-        mOverflow = overflow;
+        if(mOverflow.compareAndSet(!overflow, overflow))
-
-        if(mStateListener != null)
         {
-            mStateListener.receive(getState());
+            if(mOverflowListener != null)
+            {
+                mOverflowListener.sourceOverflow(overflow);
+            }
         }
     }
 
@@ -125,7 +123,11 @@ public class OverflowableTransferQueue<E>
         {
             mQueue.clear();
             mCounter.set(0);
-            mOverflow = false;
+            mOverflow.set(false);
+            if(mOverflowListener != null)
+            {
+                mOverflowListener.sourceOverflow(false);
+            }
         }
     }
 }

src/sample/real/IOverflowListener.java

@@ -0,0 +1,28 @@
+/*******************************************************************************
+ * sdrtrunk
+ * Copyright (C) 2014-2017 Dennis Sheirer
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ ******************************************************************************/
+package sample.real;
+
+public interface IOverflowListener
+{
+    /**
+     * Indicates that the source is in overflow state (true) or out of overflow state (false)
+     * @param overflow true to indicate an overflow state
+     */
+    void sourceOverflow(boolean overflow);
+}

src/source/Source.java

@@ -19,6 +19,7 @@ package source;
 
 import module.Module;
 import sample.SampleType;
+import sample.real.IOverflowListener;
 
 /**
  * Abstract class to define the minimum functionality of a sample data provider.
@@ -26,6 +27,7 @@ import sample.SampleType;
 public abstract class Source extends Module
 {
     protected SampleType mSampleType;
+    protected IOverflowListener mOverflowListener;
 
     public Source( SampleType sampleType )
     {
@@ -47,4 +49,25 @@ public abstract class Source extends Module
     {
     	mSampleType = sampleType;
     }
+
+    /**
+     * Registers the listener to receive overflow state changes.  Use null argument to clear the listener
+     */
+    public void setOverflowListener(IOverflowListener listener)
+    {
+        mOverflowListener = listener;
+    }
+
+    /**
+     * Broadcasts an overflow state
+     *
+     * @param overflow true if overlow, false if normal
+     */
+    protected void broadcastOverflowState(boolean overflow)
+    {
+        if(mOverflowListener != null)
+        {
+            mOverflowListener.sourceOverflow(overflow);
+        }
+    }
 }

src/source/tuner/TunerChannelSource.java

@@ -29,6 +29,7 @@ import sample.Listener;
 import sample.OverflowableTransferQueue;
 import sample.complex.Complex;
 import sample.complex.ComplexBuffer;
+import sample.real.IOverflowListener;
 import source.ComplexSource;
 import source.SourceException;
 import source.tuner.frequency.FrequencyChangeEvent;
@@ -51,7 +52,7 @@ public class TunerChannelSource extends ComplexSource implements IFrequencyChang
     private static final int BUFFER_MAX_CAPACITY = 300;
 
     //Threshold for resetting buffer overflow condition
-    private static final int BUFFER_OVERFLOW_RESET_THRESHOLD = 200;
+    private static final int BUFFER_OVERFLOW_RESET_THRESHOLD = 100;
 
     private static int CHANNEL_RATE = 48000;
     private static int CHANNEL_PASS_FREQUENCY = 12000;
@@ -101,21 +102,6 @@ public class TunerChannelSource extends ComplexSource implements IFrequencyChang
         mTunerFrequency = mTuner.getTunerController().getFrequency();
 
         mBuffer = new OverflowableTransferQueue<>(BUFFER_MAX_CAPACITY, BUFFER_OVERFLOW_RESET_THRESHOLD);
-        mBuffer.setStateListener(new Listener<OverflowableTransferQueue.State>()
-        {
-            @Override
-            public void receive(OverflowableTransferQueue.State state)
-            {
-                if(state == OverflowableTransferQueue.State.NORMAL)
-                {
-                    mLog.debug("Channel [" + mTunerFrequency + "] buffer overflow - temporary pause until processing catches up");
-                }
-                else
-                {
-                    mLog.debug("Channel [" + mTunerFrequency + "] buffer overflow cleared - resuming normal processing");
-                }
-            }
-        });
 
 	    /* Setup the frequency translator to the current source frequency */
         long frequencyOffset = mTunerFrequency - mTunerChannel.getFrequency();
@@ -126,6 +112,14 @@ public class TunerChannelSource extends ComplexSource implements IFrequencyChang
         frequencyChanged(new FrequencyChangeEvent(Event.NOTIFICATION_SAMPLE_RATE_CHANGE, mTuner.getTunerController().getSampleRate()));
     }
 
+    /**
+     * Overrides the default source overflow listener management to delegate responsibility to the overflow buffer
+     */
+    @Override
+    public void setOverflowListener(IOverflowListener listener)
+    {
+        mBuffer.setOverflowListener(listener);
+    }
 
     public void start(ScheduledExecutorService executor)
     {
@@ -175,7 +169,7 @@ public class TunerChannelSource extends ComplexSource implements IFrequencyChang
         }
         else
         {
-            mLog.warn("Attempt to stop() and already stopped tuner channel source was ignored");
+            mLog.warn("Attempt to stop() an already stopped tuner channel source was ignored");
         }
     }
 
@@ -379,6 +373,10 @@ public class TunerChannelSource extends ComplexSource implements IFrequencyChang
                     mLog.error("Error encountered during decimation process", e);
                 }
             }
+            catch(Throwable throwable)
+            {
+                mLog.error("Code error encountered during decimation process - channel thread will probably die", throwable);
+            }
 
 			/* Check to see if we've been shutdown */
             if(!mProcessing)

src/source/tuner/usb/USBTransferProcessor.java

@@ -30,6 +30,7 @@ import sample.Listener;
 import sample.OverflowableTransferQueue;
 import sample.adapter.ISampleAdapter;
 import sample.complex.ComplexBuffer;
+import sample.real.IOverflowListener;
 import source.tuner.TunerManager;
 import util.ThreadPool;
 
@@ -56,7 +57,7 @@ public class USBTransferProcessor implements TransferCallback
     private static final int FILLED_BUFFER_MAX_CAPACITY = 300;
 
     //Threshold for resetting buffer overflow condition
-    private static final int FILLED_BUFFER_OVERFLOW_RESET_THRESHOLD = 200;
+    private static final int FILLED_BUFFER_OVERFLOW_RESET_THRESHOLD = 100;
 
     private String mDeviceName;
 
@@ -101,12 +102,12 @@ public class USBTransferProcessor implements TransferCallback
         mBufferSize = bufferSize;
 
         mFilledBuffers = new OverflowableTransferQueue<>(FILLED_BUFFER_MAX_CAPACITY, FILLED_BUFFER_OVERFLOW_RESET_THRESHOLD);
-        mFilledBuffers.setStateListener(new Listener<OverflowableTransferQueue.State>()
+        mFilledBuffers.setOverflowListener(new IOverflowListener()
         {
             @Override
-            public void receive(OverflowableTransferQueue.State state)
+            public void sourceOverflow(boolean overflow)
             {
-                if(state == OverflowableTransferQueue.State.NORMAL)
+                if(overflow)
                 {
                     mLog.debug(mDeviceName + " - buffer overflow - temporary pause until processing catches up");
                 }