Mailing List Archive

otis 2002/09/14 13:58:12

Modified: contributions/webcrawler-LARM/src/de/lanlab/larm/fetcher
MessageHandler.java
Log:
- Added a comment about a small bug with the messageQueue's status.
- A few minor cosmetic changes.

Revision Changes Path
1.4 +23 -19 jakarta-lucene-sandbox/contributions/webcrawler-LARM/src/de/lanlab/larm/fetcher/MessageHandler.java

Index: MessageHandler.java
===================================================================
RCS file: /home/cvs/jakarta-lucene-sandbox/contributions/webcrawler-LARM/src/de/lanlab/larm/fetcher/MessageHandler.java,v
retrieving revision 1.3
retrieving revision 1.4
diff -u -r1.3 -r1.4
--- MessageHandler.java 1 Jun 2002 18:55:15 -0000 1.3
+++ MessageHandler.java 14 Sep 2002 20:58:12 -0000 1.4
@@ -61,15 +61,15 @@
import de.lanlab.larm.storage.LinkStorage;

/**
- * this is a message handler that runs in its own thread.
+ * This is a message handler that runs in its own thread.
* Messages can be put via <code>putMessage</code> or <code>putMessages</code>
* (use the latter whenever possible).<br>
- * The messages are passed to the filters in the order in which the filters where
+ * Messages are passed to the filters in the order in which the filters where
* added to the handler.<br>
- * They can consume the message by returning null. Otherwise, they return a Message
- * object, usually the one they got.<br>
+ * They can consume a message by returning <code>null</code>. Otherwise, they
+ * return a Message object, usually the one they got.<br>
* The filters will run synchronously within the message handler thread<br>
- * This implements a chain of responsibility-style message handling
+ * This implements a chain of responsibility-style message handling.
* @version $Id$
*/
public class MessageHandler implements Runnable, LinkStorage
@@ -111,27 +111,28 @@
SimpleObservable messageQueueObservable = new SimpleObservable();
SimpleObservable messageProcessorObservable = new SimpleObservable();

- public boolean isWorkingOnMessage()
- {
- return workingOnMessage;
- }
-
/**
* messageHandler-Thread erzeugen und starten
*/
public MessageHandler()
{
- t = new Thread(this,"MessageHandler Thread");
- t.setPriority(5); // higher priority to prevent starving when a lot of fetcher threads are used
+ t = new Thread(this, "MessageHandler Thread");
+ // higher priority to prevent starving when a lot of fetcher threads are used
+ t.setPriority(5);
t.start();
}

+ public boolean isWorkingOnMessage()
+ {
+ return workingOnMessage;
+ }
+
/**
* join messageHandler-Thread
*/
public void finalize()
{
- if(t != null)
+ if (t != null)
{
try
{
@@ -174,7 +175,6 @@
messageProcessorObservable.addObserver(o);
}

-
/**
* insert one message into the queue
*/
@@ -197,8 +197,8 @@
{
for(Iterator i = msgs.iterator(); i.hasNext();)
{
- Message msg = (Message)i.next();
- messageQueue.insert(msg);
+ Message msg = (Message)i.next();
+ messageQueue.insert(msg);
}
messageQueueObservable.setChanged();
messageQueueObservable.notifyObservers(new Integer(1));
@@ -247,8 +247,12 @@
{
synchronized(this.queueMonitor)
{
+ // note: another thread may put a new message in the queue after
+ // messageQueue.size() is called below, which would result in the
+ // inconsistent state: messageWaiting would be set to false, but
+ // the queue would actually not be empty
m = (Message)messageQueue.remove();
- if(messageQueue.size() == 0)
+ if (messageQueue.size() == 0)
{
messagesWaiting = false;
}
@@ -279,7 +283,7 @@
}
catch(ClassCastException e)
{
- System.out.println("MessageHandler:run: ClassCastException(2): " + e.getMessage());
+ System.out.println("MessageHandler:run: ClassCastException(2): " + e.getMessage());
}
}
}




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