Re: Using custom classloader
2014-06-04 19:46 GMT+04:00 Don Asper don.as...@sas.com: Hi: I want my web apps running on Tomcat 7.0.35 to use a custom classloader. The reason is that I want each web app classloader instance to do some processing to set up the classpath for the web app it belongs to. I have the following questions: 1) Is org.apache.catalina.loader.WebappClassLoader a good class to derive my custom classloader from? Is it a good choice going forward for later versions of Tomcat? 2) Is there a recommended way for my custom classloader to identify which web app it belongs to? It needs to identify which web app it is for so that it will know what jars to put on its classpath. Thanks! Look at VirtualWebappLoader. Maybe it suits your needs as is. Also the same trick that it does can be performed from a Listener. There is no need to extend WebappLoader just for that. A Listener and a WebappLoader have access to Tomcat's Context class and can get the paths. The VirtualWebappLoader is not available in Tomcat 8, replaced by new Pre/Post/... resources APIs. Beware that webapp's classloader should be able to produce class path that is used by JSP compiler (Eclipse JCP or by external javac depending on how your Tomcat is configured). Tomcat WebappClassLoader has API for that. Best regards, Konstantin Kolinko - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Using custom classloader
Hi: I want my web apps running on Tomcat 7.0.35 to use a custom classloader. The reason is that I want each web app classloader instance to do some processing to set up the classpath for the web app it belongs to. I have the following questions: 1) Is org.apache.catalina.loader.WebappClassLoader a good class to derive my custom classloader from? Is it a good choice going forward for later versions of Tomcat? 2) Is there a recommended way for my custom classloader to identify which web app it belongs to? It needs to identify which web app it is for so that it will know what jars to put on its classpath. Thanks!
Re: Using custom classloader
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Don, On 6/4/14, 11:46 AM, Don Asper wrote: Hi: I want my web apps running on Tomcat 7.0.35 to use a custom classloader. The reason is that I want each web app classloader instance to do some processing to set up the classpath for the web app it belongs to. Can you be more specific? Perhaps you don't actually need to write a new ClassLoader... you may be able to configure the existing ClassLoader to behave the way you want, or possibly use a non-ClassLoader-related solution. I have the following questions: 1) Is org.apache.catalina.loader.WebappClassLoader a good class to derive my custom classloader from? Yes. Is it a good choice going forward for later versions of Tomcat? Probably. I don't think that class (name) has changed significantly in a very long time. If you hook-into the constructor or lifecycle methods you should be good. Remember: always test with new versions :) 2) Is there a recommended way for my custom classloader to identify which web app it belongs to? It needs to identify which web app it is for so that it will know what jars to put on its classpath. If you are using WebapClassLoader as your parent, you can call super.getContextName(), but that will just get you the name of the context, not the location of the deployment artifact. What information do you actually need? - -chris -BEGIN PGP SIGNATURE- Version: GnuPG v1 Comment: GPGTools - http://gpgtools.org Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBCAAGBQJTj7f0AAoJEBzwKT+lPKRYG3AP/3gJCphgLXN8hZvojSz760CO JRzw+YR3qubhFPH+K2diwveA4tLwIpmL7rMiCljXIVZz+q5illbYtrMR6Ou9nCmt k7L9R2rjX5Fyr+Eew4qevXQHL+0V0MbVsuRd9Gs9D4LVvMgNpOb1ArhIkweZEi2A 67GTPKENU+o29yJrxXU/19EMbyItu6O/w26boPeX6+7MQXfvSycSeJZdytNA3Sws psiEf+5/5th2jppDB2aoS/lpZbAoODLUPkeOryGZPjAL5KFCqVAUvhtV/CmfHqKw VSbaa6XCvhFlijXETArWiSgjdaWm5dBEWK+XdKhAV9PWt10zBHeL4+vXdsan3K6Z 3tXy9ceMTeHC9oXAJDOcdXIjiL8wIJlPOH0P05/cbnMaGL2ItKu1H+V6y9NqvKXw hr07SypVdWzjez+1s3u0Uv7hzyoRXVtfbA5vpCAOgo0jL04bLLfzlJ/JE+yZwdk1 Y37XBxRWvRpUfeax0+U/q5X+8Io3bBHwBzUW9JPJnQE1iLxej/H4Db1Fp+kXnVaz GtwLYEAechGXgAnZF+0msocTdLb7OjecCcKmVDmwHayUqHPAQNrh0Bn2vaw4EWef HkV6XH3Rt3bcvgw+CUQoiDa+k02BTtBOCLRlCCYc6L8MTL9wh2uVUWIrijBNMTjn jETFSqYlIC2H6O5mGiJ2 =Lc35 -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
RE: Embedded Tomcat stops deploying WARs when using custom ClassLoader
It would appear that my problem was solved by simply changing the line 'new Catalina();' to 'new Embedded();', so now it unpacks. -Original Message- From: Andrew McDowall [mailto:[EMAIL PROTECTED] Sent: 13 April 2006 16:56 To: users@tomcat.apache.org Subject: Embedded Tomcat stops deploying WARs when using custom ClassLoader Hi, I am currently working on a fairly complex system which provides a means to incorporate 'pluggable' functionality using an embedded Tomcat - essentially it allows WARs to be dropped into a specific directory, the embedded Tomcat then unpacks and deploys the WAR. This has been working without any problems up until a few days ago when I started incorporating our own proprietary ClassLoader into the system. The rationale behind the ClassLoader is that I need to provide a degree of separation between certain sub-components of the system while still providing common shared libraries for all components - much like the ClassLoading solution provided by Catalina. My own ClassLoader now allows me to navigate a tree of child ClassLoaders in an order different to that of the standard Java delegation model ie: in my solution I wish to perform a depth-first search rather than simply being limited to one branch. The solution implemented is working (give or take a few minor flaws) except for now the embedded Tomcat no longer deploys WARs. At first I believed this to be an issue with the ContextClassLoader for the Thread in which the embedded Tomcat runs, but after investigation I am not so sure. It should be noted that the embedded Tomcat itself does not produce any errors so I am at a loss to understand exactly why it has stopped working, it's as if it is failing silently. None of the configuration for Tomcat has changed between the versions using the System ClassLoader and the new version using the new custom ClassLoader. I would be very grateful for any help with this problem, thanks in advance. Andy McDowall --- Disclaimer --- Unless otherwise agreed expressly in writing by a Director of Edina Software, this communication is to be treated as confidential and the information in it may not be used or disclosed except for the purpose for which it has been sent. If you have reason to believe that you are not the intended recipient of this communication, please contact the sender immediately. __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ --- Disclaimer --- Unless otherwise agreed expressly in writing by a Director of Edina Software, this communication is to be treated as confidential and the information in it may not be used or disclosed except for the purpose for which it has been sent. If you have reason to believe that you are not the intended recipient of this communication, please contact the sender immediately. __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Embedded Tomcat stops deploying WARs when using custom ClassLoader
Hi, I am currently working on a fairly complex system which provides a means to incorporate 'pluggable' functionality using an embedded Tomcat - essentially it allows WARs to be dropped into a specific directory, the embedded Tomcat then unpacks and deploys the WAR. This has been working without any problems up until a few days ago when I started incorporating our own proprietary ClassLoader into the system. The rationale behind the ClassLoader is that I need to provide a degree of separation between certain sub-components of the system while still providing common shared libraries for all components - much like the ClassLoading solution provided by Catalina. My own ClassLoader now allows me to navigate a tree of child ClassLoaders in an order different to that of the standard Java delegation model ie: in my solution I wish to perform a depth-first search rather than simply being limited to one branch. The solution implemented is working (give or take a few minor flaws) except for now the embedded Tomcat no longer deploys WARs. At first I believed this to be an issue with the ContextClassLoader for the Thread in which the embedded Tomcat runs, but after investigation I am not so sure. It should be noted that the embedded Tomcat itself does not produce any errors so I am at a loss to understand exactly why it has stopped working, it's as if it is failing silently. None of the configuration for Tomcat has changed between the versions using the System ClassLoader and the new version using the new custom ClassLoader. I would be very grateful for any help with this problem, thanks in advance. Andy McDowall --- Disclaimer --- Unless otherwise agreed expressly in writing by a Director of Edina Software, this communication is to be treated as confidential and the information in it may not be used or disclosed except for the purpose for which it has been sent. If you have reason to believe that you are not the intended recipient of this communication, please contact the sender immediately. __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __
