Listener or watchdog is needed

Hi,
I need to implement a listener which can monitor a message queue, so when new message comes into the queue, it will fire a signal to invoke other application/thread.
Currently, I have to do a polling at specified interval. But the polling is somewhat expensible, say need database connection, enquiry and the interval is 5 seconds.
Thanks in advance.
Harv

if you are really using a queing system, like MQSeries or JMS variants, this is done for you already. But it looks like you are using a database table as a queue and polling the table for latest entries, you can poll using a thread is not that bad. But if you have the latest Oracle and others that have java build in, you should be able to use triggers and have java stored procedures notify 'observers' using sockets or RMI (I only have oracle 8i and that is 1.1.8 I believe). Ideally, I will like to try some JINI etc and cannot wait till I get Oracle 9i, assuming that has 1.2!

Similar Messages

JComboBox listener - which do i need?

Hi,
What listener do I need, so that I know when a new item is selected in the combo box? I only want to know when the item is selected. I know there is the itemListener but it fires an event for each item in the combo box until it gets the item that is being selected. I only want to be notified once.
thanks

          String[] model = new String[] { "one", "two", "three" };
          final JComboBox comBox = new JComboBox( model );
          comBox.addActionListener(new ActionListener() {
               public void actionPerformed(ActionEvent evt) {
                    System.out.println( comBox.getSelectedItem() );
          });

Listening to Radio. Need you guys' advice.

Hi guys,
I use Blackberry curve/Sprint on $30 SERO plan which covers unlimited data/text/weekend call/night call starting 7pm, and 500 min talk. It's such a cheap and great plan I don't really want to give up. The thing is, the Blackberry su*ks.
I am willing to give up the plan for an iPhone 3gs if it works for me. I listen to news/talk show or music radios all day long, not exactly all day long 'cause the blackberry refuses to work that hard, and sometimes it doesn't make it through a day. shame.
Checking the iPhone 3gs' tech specs, I found that it holds up to 5 hours on 3G. Since it doesn't have FM radio, the only way I listen to radio stations is using its 3g network, which means it's not going to make it through a day, either, I guess.
Any advice? Should I just give up and buy a mp3 player with FM radio function?
Message was edited by: GoodmorningNightmare

GoodmorningNightmare wrote:
Any advice? Should I just give up and buy a mp3 player with FM radio function?
Well, that would probably be the best way to go; then you'll not deplete the iPhone's charge.
But I was able to listen to many internet radio stations on my original 2G (EDGE) iPhone. So you could disable 3G and probably substantially extend battery life.
Phil

I have a sony ICF-cs15ip listening station and I need to know what to purchase and from whom to make my new iphone5s work with the 30 pin

what kind of adapter and where can I buy to work with my Sony ICF-CS15ip listening station with my Iphone 5s. The dock has a 30 pin which will not work with the new phone

Apple Store lightning to 30 pin adapter
http://store.apple.com/us/product/MD823ZM/A/lightning-to-30-pin-adapter?fnode=45
works perfectly but avoid cheap copies elsewhere they generally charge but no sound

How come most of my songs i purchased on itunes don't work? It says there is no file found for it when I bought the songs. I need help!

I bought many songs from Itunes and when I went to plug in and download my songs onto my laptop it only downloaded 20 songs that I purchased and the rest were counted as "There was no file to support this song" And I don't know how that even happened and now on my ipad none of the cover art for the purchased songs show up and none of the songs I bought on itunes are shown and play when I go to the purchase part of the music itunes store and its really ******* me off making me feel like I just wasted money on buying songs I can never listen too! I need to know how I can fix it ASAP.

You can redownload the songs as many times as you want, the "one time regrant" no longer exists. Make sure you are using the same apple id on both your dead itouch and your iphone 4. On your iphone 4 go to the itunes app > Purchased (may be under more based on your settings) at the top click not on this iphone, click all songs then click the little cloud next to each song you want to redownload. It will prompt you for your id and password and the begin your download

APEX Listener on Weblogic licensing - SE or EE

Does the APEX listener on Weblogic use any Weblogic Enterprise Edition features like clustering or is Weblogic Standard Edition good enough? I'm assuming you would need to license Welogic for the APEX listener right?
Also do we have any sizing guidelines for APEX listener on Weblogic. The real question is if the APEX application we have met our SLA's on a 1 CPU box, without the APEX listener, after migrating to Weblogic - APEX Listener, would we be needing more, less or the same CPU capacity.

Hello,
the APEX Listener itself is stateless, so you can cluster it easily if you want or have to.
APEX Listener is licensed with APEX, not with WLS. You can use a variety of J2EE containers that meet the requirements. In addition to WLS, Oracle supports the use of OC4J (either part of OAS or standalone) and GlassFish. In fact, the APEX Listener ships with an embedded version of GlassFish.
Despite the support aspect, there are people who successfully run the Listener on the GlassFish's Open Source Edition or Apache Tomcat.
Concerning your SLAs: The Listener will do something for you, so of course it will need the CPU. How much load it will generate depends on your usage scenario. Your post sounds like you already use APEX with a different web server than the Listener. If that guess is right, it would be helpful to know which web server you use now and how much CPU time it consumes.
-Udo

APEX Listener 2.0.1 does not restart on power-up of system

APEX Listener 2.0.1
APEX 4.2.2
Oracle EE 11gR2
Linux RHEL 6.3
GlassFish 3.1.0
After rebooting my Linux server with the above configuration, the APEX Listener is down and needs to be restarted via GlassFish. What may be causing this? How can I get the APEX Listener via GlassFish to restart on system power-up?
NOTE: I did not have this issue when using APEX Listener 1.4 with the same GlassFish server.
Thank you.

Found the issue. chkconfig was starting GlassFish before the database was up and running. Changed chkconfig parameters in startup scripts. Works fine.

Can't parse "bad" characters - need help

Hey everyone, this should be simple. I am trying to parse (DOM parser) and XML string that has some funky characters in it. I am getting the following error:
Illegal XML character: & # x 1 d ; (had to use spaces so that it would print out properly...otherwise: 
I have a findAndReplace method that I can use to replace the bad characters with their proper values (copy paste from Word to notepad of single quotes really screws things up), but I can't seem to get it to work. What should I pass in to be replaced? I know that this is a hexadecimal for '29', but I can't seem to get my findAndReplace to work by passing in &#x1d, & # x 1 d ;, or java.lang.String.valueOf(29). Please help, thanks!
FYI...here's my findAndReplace method.
public static String findAndReplace(String original, String replaceThis, String withThis) {
if (original==null || replaceThis==null || withThis==null) {
return null;
int i = original.indexOf(replaceThis);
if (i == -1) {
return original;
int replaceThisSize = replaceThis.length();
int withThisSize = withThis.length();
while (i != -1) {
String beforeString = original.substring(0, i);
String afterString = original.substring(i + replaceThisSize);
original = beforeString + withThis + afterString;
i = original.indexOf(replaceThis, i + withThisSize);
return original;

warnerja, you're right. That character should not be
there. However, I can not guarantee that it will not
be there as it comes from a different system and
people are pasting Word docs into this system all the
time. You can train people all you want, but they
don't always listen. So, I need to make sure my code
doesn't blow up when the do do this. Hence my issue.I'd follow the GIGO (garbage in, garbage out) principle. Are you also going to need to code it to read their minds when they provide no sensible input whatsoever, like:
<hey, figure this>junk<out/>man</hey, figure this>

PDF printing using APEX Listener

Hi -
I have one report region a an apex page which displays a classic report based on a simple query. I also have a some header information above the report which are the application item information passed from the previous page. I am trying to generate a PDF report(using APEX listener), the report comes fine but it doesn't show the header information that is displayed above the report. Is there a way to do that? I tried putting some values in "Print Attributes" --> "Page Header" section but it just shows it as static text. Please provide your expertise.
APEX version: 4.2.2
Oracle:11gR2
Printing Engine: Apex Listener
Thanks,
-Seenu

You will need to build an Xsl document and load it into APEX.. Here is the link showing how to do advanced printing with APEX..:
Marc Sewtz: PDF Printing with Oracle Application Express 4.2.2
Thank you,
Tony Miller
LuvMuffin Software
Ruckersville, VA

What MIME plug-in do I need?

Hello,
I'm a new Mac user so things are still a bit foggy.
I'm trying to open "what's on now" from a radio station but it gives me this message:
The page has content of MIME type “application/x-oleobject”.
Because you don’t have a plug-in installed for this MIME type, this content can’t be displayed.
How do I get what I need to be able to listen online?

You need Flip4Mac which replaces Microsloth's Windows Media Player. However, you don't mention which machine. IIRC, it's only for PPC machines. There's nothing comparable for ICBMs (Intel-chip-based Macs).
BTW, since you're a newcomer to the Mac, peruse Switching from Windows to Mac OS X and Basic Tutorials on using a Mac

Listener configuration for 2 db instance in a single node

Hi,
I have configure a 11gR2 server with 2 db instance (A and B), but I have only one listener (default) to server this two db instances.
Is this the recommended configuration or should I have one listener for each db instance? e.g Listener_A and Listener_B. I think it will be usefull in cases when I need to block the access to one db instance (A) without shutting down the database, by just turning off the proper Listener.
With my current configuration I am not able to do that since if I turn of the only listener that I have both dbs will not receive any other connections.
Am I correct?
Regards,
Edited by: ashum on May 13, 2011 8:21 AM

You are right that there is some value in going to the trouble to set up a separate listener for each database. Whether you take this approach depends mainly on how satisfied you are with the alternatives and how much trouble you want to incur in setting up and maintaining multiple listeners. We use separate listeners for each of our databases and really like the granularity it provides in limiting the scope of outages.
If you take the multiple listener approach, you will need to either use separate ports for each listener, or bring up a virtual ip on your server so that the second listener can run on the virtual ip.

Popup + before phase listener + commandlink issue

All,
I have a before phase listener configured on a page to open a popup and it works pretty well i.e. the popup gets opened when the page is loaded. Now i want to show the same popup when the user clicks on the commandLink. So i configured the commandLink to have a showPopupbehaviour as its child. The issue is when i click on the command link the popup is not getting opened. However if i remove the call to the before phase listener (), the popup is getting invoked from the command link.
Please advice whats wrong in this case ? Ideally both should be working independently.
I tried setting the immediate and auto submit also but no effect.
thnks
Jdev 11.1.1.5

Hi,
using af:showPopupBehavior issues a request to the server, which then also is handled by your phase listener. So you need to add some logic to your phase listener to not process its action when the command button is pressed. You can e.g. set the command button to partialSubmit = true and then check if the request is a partial request AdfContext.getCurrentInstance().isPartialRequest(facesContext) This way the phase listener opens the popup when a page loades but no longer after.
Frank

Trying to add another DB under SCAN via DBCA "Default listener LISTENER is not Configured in the grid infrastructure home"

Trying to install another DB under RAC using SCAN listener on a new port. DBCA gives error "Default listener LISTENER is not Configured in the grid infrasturcture home".
Have tried srvctl config listener, srvctl start listener to start the listener. Still not able to get past the DBCA error. What am I missing? Do not want to start LISTENER on port 1521 as SCAN is running on 1521.

No your Database config does use hostname/ip + port or a tns-entry pointing to the local_listener. Neither method does care for the home the listener is running from.
You will however have to take care of the entries in the clusterware, as the listener is a controlled resource. If you manually relocate it, then it will only work until next restart of crs stack.
The simplest way to switch the home is by running first netca from database home and delete the listener and then switch to grid home run netca again and create the listener.
netca will take care of registering it with crs with the correct environment settings. You will have a short period where your rac won't have a listener and therefore won't accept new connections until the new listener is up and running.
Relocating the current listener requires to modify several parameters via crsctl in the cluster registry, but allows doing this node by node without complete outage.
If you want to go that way, then create another listener from grid home and compare the settings of current listener and of the new listener. You will need to update several parameter before you can relocate it.
Run this command to show the current settings and compare it to the listener from grid home:
crsctl stat res ora.LISTENER.lsnr -p
You will need to modify serveral parameters, ACTION_SCRIPT,AGENT_FILENAME,ALIAS_NAME,ORACLE_HOME and the ACL
Modify works like this, for ACL you must use the encasing single apostrophe ' and run it as root:
crsctl modify res ora.LISTENER.lsnr -attr "ACL='owner:oracle:rwx,pgrp:oinstall:rwx,other::r--'"
I would recommend Version 1 if short outage is acceptable. For both variants verify that you can resolve all tnsnames entries in both homes.
Regards
Thomas

Questions on sqlnet.ora, listener.ora files in RAC environment.

Experts,
I've some confusion with below files in RAC environment.
sqlnet.ora
listener.ora
These files are available in two locations: <GRID_HOME> & <DB_HOME>.
My questions:
1. Why do we have two versions of files ?
2. When I query lsnrctl status from BOTH the homes, it says it is using listener.ora from <GRID_HOME> as shown below.
Listener Parameter File D:\app\11.2.0\grid\network\admin\listener.ora
3. What is the use of files which are in <DB_Home>
4. If you make some changes to listener using "Netmgr" tool, we expect it will update listener.ora in <GRID_HOME>. Interestingly, it is changing the contents of listener.ora in <DB_HOME> .
Can anyone please clarify it ?
Thanks in advance.

859875 wrote:
1. Why do we have two versions of files ? In the past, the CRS s/w did not include ASM (ASM did not provide support for cluster voting and registration disks). Thus the networking components such as SQL*Net and the Listener were not part of the CRS installation.
With Grid Infrastructure, ASM supports cluster voting and registration disks and is recommended to be used for that (as oppose to the old style of raw disks or using an external cluster-based cooked file system like <i>ocfs</i>). And with ASM comes the SQL*Net networking layer and s/w (such as the Listener). As ASM ships with Grid Infrastructure, it now also includes the same networking layer as what the RDBMS installation will. Thus both <GRID_HOME> and <DB_HOME> will contain the same networking components.
However, only a single Listener is for example needed. And that can only run from a single base location. So for operational use, only one version will be actively in use.

Where can I find IDOC Listener (xMII 12.05) .It is not in DataServices.

Hi all,
I can not find IDOC Listener in Data Services in xMII version 12.05.
Where can I find the IDOC Listener? Must I set up it first? Or must I do some configurations for IDOC Listener?
Thanks.

Cemil,
in MII 12.0.x you will find the Listener under Message Services -> Message Listener.
If you need to run a transaction after receiving a IDOC, than you need also to configure
a Rule under Message Services -> Processing Rule Editor.
Under the link below you will find the Documentation for Message Services:
http://wbhelp.sap.com/manufacturing/xmii_120/en/45/aa5d17b8f52e78e10000000a155369/frameset.htm
Regards
Pedro

Listener or watchdog is needed

Similar Messages

Maybe you are looking for