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| <== Date ==> | <== Thread ==> |
|---|
| Subject: | Re: CAJ Options |
| From: | "J. Lewis Muir" <[email protected]> |
| To: | [email protected] |
| Date: | Tue, 15 May 2007 17:09:13 -0400 |
I had an include file that wasn't included. Fancy that ;-)
Still, have the following code —------------------------------------------- try { URL codebase=this.getCodeBase(); String host=codebase.getHost(); System.out.println("Configuration starting"); DefaultConfiguration conf=new DefaultConfiguration("applet"); System.out.println("Context created"); conf.setAttribute("class","com.cosylab.epics.caj.CAJContext"); System.out.println("Attribute Added"); System.out.println("Instance created"); // Get the JCALibrary instance jca=JCALibrary.getInstance(); System.out.println("Instance initialization passed"); // System.setProperty("com.cosylab.epics.caj.CAJContext.addr_list",host); // System.setProperty("com.cosylab.epics.caj.CAJContext.auto_addr_list","false"); conf.setAttribute("com.cosylab.epics.caj.CAJContext.addr_list",host); conf.setAttribute("com.cosylab.epics.caj.CAJContext.auto_addr_list","false"); conf.setAttribute("com.cosylab.epics.caj.CAJContext.connection_timeout","30.0"); conf.setAttribute("com.cosylab.epics.caj.CAJContext.beacon_period","15.0"); conf.setAttribute("com.cosylab.epics.caj.CAJContext.repeater_port","5065"); conf.setAttribute("com.cosylab.epics.caj.CAJContext.server_port","5064"); conf.setAttribute("com.cosylab.epics.caj.CAJContext.max_array_bytes","16384"); conf.setAttribute("com.cosylab.epics.caj.CAJContext.thread_pool_size","5"); System.out.println("Creating context"); // ctxt=jca.createContext(JCALibrary.CHANNEL_ACCESS_JAVA); ctxt=jca.createContext(conf); System.out.println("Context creation passed"); // System.setProperty("com.cosylab.epics.caj.CAJContext.addr_list",host); // System.setProperty("com.cosylab.epics.caj.CAJContext.auto_addr_list","false"); } catch(Exception ex) { System.err.println("Initialization failed for " + dpm.dataSource+":\n" + ex + "\n"); System.exit(1); } —-------------------------------------------
and it's producing the following error. —-------------------------------------------
Configuration starting Context created Attribute Added Instance created Instance initialization passed Creating context Initialization failed for Util1:Tot:KW: gov.aps.jca.CAException: Unable to create context
java.security.AccessControlException: access denied (java.lang.RuntimePermission exitVM.1) at java.security.AccessControlContext.checkPermission(Unknown Source) at java.security.AccessController.checkPermission(Unknown Source) at java.lang.SecurityManager.checkPermission(Unknown Source) at java.lang.SecurityManager.checkExit(Unknown Source) at java.lang.Runtime.exit(Unknown Source) at java.lang.System.exit(Unknown Source) at Applet1.initDPM(Applet1.java:295) at Applet1.init(Applet1.java:62) at sun.applet.AppletPanel.run(Unknown Source) at java.lang.Thread.run(Unknown Source)
—------------------------------------------- By looking at the code, you can see that it gets down to doing the actual createContext call before failing.
No, I'm not running it in the Sun Applet viewer. Believe it or not, things were working fine in the viewer, and it would even read the properties file successfully. Turns out the problem wasn't the properties file at all, but this one next in the code.
I'm using Eclipse to create a .jar file, and I've got a WEB page that invokes the applet in IE.
Curious and curiouser... David Dudley
David Dudley wrote:"J. Lewis Muir" <[email protected]> 5/15/2007 3:40 PM >>>For some reason I get a "cannot find symbol" for the line
DefaultConfiguration conf=new DefaultConfiguration("applet");
Can't seem to get past that line.
Hi, David.
Are you getting that error at compile time or run time? What is producing that error? Is there a stack trace? Are you running your applet with the Sun JDK's appletviewer program?
-lewis
David Dudley wrote:"J. Lewis Muir" <[email protected]> 5/15/2007 1:35 PM >>>After putting a bunch more comments in my Applet file, what I find is that the call to JCALibrary.getInstance() completes successfully, but the call to jca.createContext() fails.Hi, David.
My code is: —------------------------- try { URL codebase=this.getCodeBase(); String host=codebase.getHost();
// Get the JCALibrary instance jca=JCALibrary.getInstance();
System.out.println("Instance initialization passed"); System.setProperty("com.cosylab.epics.caj.CAJContext.addr_list",host); System.setProperty("com.cosylab.epics.caj.CAJContext.auto_addr_list","false");
// Create a thread safe context with default configuration values ctxt=jca.createContext(JCALibrary.CHANNEL_ACCESS_JAVA); System.out.println("Context creation passed"); System.setProperty("com.cosylab.epics.caj.CAJContext.addr_list",host); System.setProperty("com.cosylab.epics.caj.CAJContext.auto_addr_list","false"); } catch(Exception ex) { System.err.println("Initialization failed for " + dpm.dataSource+":\n" + ex); System.exit(1); } —-------------------------
The console outputs: Instance initialization passed Initialization failed for Util1:Tot:KW: java.security.AccessControlException: access denied (java.util.PropertyPermission com.cosylab.epics.caj.CAJContext.addr_list write) java.security.AccessControlException: access denied (java.lang.RuntimePermission exitVM.1) at java.security.AccessControlContext.checkPermission(Unknown Source) at java.security.AccessController.checkPermission(Unknown Source) at java.lang.SecurityManager.checkPermission(Unknown Source) at java.lang.SecurityManager.checkExit(Unknown Source) at java.lang.Runtime.exit(Unknown Source) at java.lang.System.exit(Unknown Source) at Applet1.initDPM(Applet1.java:279) at Applet1.init(Applet1.java:61) at sun.applet.AppletPanel.run(Unknown Source) at java.lang.Thread.run(Unknown Source)
Line 279 (the error line) is the line number of the System.exit(1) function call.
ideas??
David Dudley
It looks like it might be failing because the applet does not have write permission to *set* the system property "com.cosylab.epics.caj.CAJContext.addr_list" in the System.setProperty call.
You could try the approach I suggested earlier to see if it might work instead:
DefaultConfiguration conf = new DefaultConfiguration("applet"); conf.setAttribute("class", "com.cosylab.epics.caj.CAJContext"); ... JCALibrary.getInstance().createContext(conf);
-lewis
On May 15, 2007, at 12:16 , David Dudley wrote:Kay-Uwe Kasemir <[email protected]> 5/15/2007 12:13 PM >>>
OK, all you JCA and CAJ people, here's a problem for you-Interesting.
I'm setting up JCA/CAJ to run through an applet. How do I prevent them
from *attempting* to find the JCALibrary.properties file?
When an applet tries to find the file, it creates an access security exception, since Applets, by nature, can't access the underlying file system.
I tried doing System.setProperty commands to set 'com.cosylab.epics.caj.CAJContext' to values before the createContext, but the moment that createContext is accessed, I get an error.
In jca-2.3.0/src/core/gov/aps/jca/JCALibrary.java there's this code:
try {
InputStream is = JCALibrary.class.getResourceAsStream ( "JCALibrary.properties" );
if (is == null)
throw new RuntimeException("resource not found.");
_builtinProperties.load( is );
} catch( Throwable ressourceEx ) {
System.out.println( "Unable to load default configuration....);
}
I would think the worst that can happen is a println, and your System.setProperty calls would actually win.
But maybe that attempt to read a file does worse things to an applet, something that the catch() doesn't catch? I'd try to change that code section somewhat to see what's happening in your case.
-Kay