RE: Possible TaskDef donation
Why not posting it? Seems interesting enough, and once it's posted people can start using it or tweaking it. Best way to post it is to open a new Enhancement in Ant's BugZilla. This keeps everything in one place (posted sources, JARs, ZIPs, whatever and the discussions about it). Using URLClassLoader works fine, but does require having the dependent classes available. Maybe somehow Ant's can be leveraged to not require the dependencies. --DD -Original Message- From: Berin Loritsch [mailto:[EMAIL PROTECTED] Sent: Thursday, March 13, 2003 9:57 AM To: [EMAIL PROTECTED] Subject: Re: Possible TaskDef donation Dominique Devienne wrote: > This is indeed interesting. I do something quite similar for another purpose > (scans a JAR for all classes having a give static method signature, executes > all these methods, gathering the meta-info required, generate a XML file > then stuck into the JAR's META-INF directory). > > Something I do is to restrict scanning classes to only those that match a > given patternset to speed things up (you often know which part of your > package tree to look things, or could use a naming convention to find things > faster). This makes the scanning quite a bit faster (we have big JARs). > > All this to say that you specific use case if very useful, but the more > generic action all scanning the classes of a JAR and doing something that > ultimately updated the JAR somehow would be even more useful. Allowing to > plug over 'actions' rather than the default 'looking for services' would be > very very useful IMHO. Easy change to make--I can make it a protected action (the actual check). > What are your dependencies? BCEL? Do you load the actual classes (so need > dependent classes on the classpath)? Standard JVM. I use JarFile to read the JAR contents, and JarOutputStream to write the new JAR. I construct a new URLClassLoader that uses the current classloader as the parent, and loads the input JAR in as well. I then scan the contents of the JAR only looking at the ".class" entries. I load the class, and perform my checks on the class itself. > Thanks for sharing this with us. --DD > > PS: BTW, I don't think you can edit the JAR in place... Would be nice though. I guess we could make it something where you can use a directory instead of the JAR. It would alter the scanning code though. Do you want me to post what I have?
Re: Possible TaskDef donation
Dominique Devienne wrote: This is indeed interesting. I do something quite similar for another purpose (scans a JAR for all classes having a give static method signature, executes all these methods, gathering the meta-info required, generate a XML file then stuck into the JAR's META-INF directory). Something I do is to restrict scanning classes to only those that match a given patternset to speed things up (you often know which part of your package tree to look things, or could use a naming convention to find things faster). This makes the scanning quite a bit faster (we have big JARs). All this to say that you specific use case if very useful, but the more generic action all scanning the classes of a JAR and doing something that ultimately updated the JAR somehow would be even more useful. Allowing to plug over 'actions' rather than the default 'looking for services' would be very very useful IMHO. Easy change to make--I can make it a protected action (the actual check). What are your dependencies? BCEL? Do you load the actual classes (so need dependent classes on the classpath)? Standard JVM. I use JarFile to read the JAR contents, and JarOutputStream to write the new JAR. I construct a new URLClassLoader that uses the current classloader as the parent, and loads the input JAR in as well. I then scan the contents of the JAR only looking at the ".class" entries. I load the class, and perform my checks on the class itself. Thanks for sharing this with us. --DD PS: BTW, I don't think you can edit the JAR in place... Would be nice though. I guess we could make it something where you can use a directory instead of the JAR. It would alter the scanning code though. Do you want me to post what I have?
RE: Possible TaskDef donation
This is indeed interesting. I do something quite similar for another purpose (scans a JAR for all classes having a give static method signature, executes all these methods, gathering the meta-info required, generate a XML file then stuck into the JAR's META-INF directory). Something I do is to restrict scanning classes to only those that match a given patternset to speed things up (you often know which part of your package tree to look things, or could use a naming convention to find things faster). This makes the scanning quite a bit faster (we have big JARs). All this to say that you specific use case if very useful, but the more generic action all scanning the classes of a JAR and doing something that ultimately updated the JAR somehow would be even more useful. Allowing to plug over 'actions' rather than the default 'looking for services' would be very very useful IMHO. What are your dependencies? BCEL? Do you load the actual classes (so need dependent classes on the classpath)? Thanks for sharing this with us. --DD PS: BTW, I don't think you can edit the JAR in place... -Original Message- From: Berin Loritsch [mailto:[EMAIL PROTECTED] Sent: Wednesday, March 12, 2003 4:13 PM To: [EMAIL PROTECTED] Subject: Possible TaskDef donation Currently, if you want to support the JAR Services standard set forth by Sun, you have to create a file with an interface name in META-INF/services and list all the implementations. This can get to become a problem if we are adding and removing classes, and we forget to update this hand maintained file. I wrote an ANT task that will scan an existing JAR, and find all the classes that implement the specified interfaces. The task verifies that the supplied service name *is* in fact an interface, and then it checks every class in the JAR to see if it implements that interface. After it collects all this information it adds a new entry for each interface, with the list of implementations for each service. For now it needs to use an input jar and an output jar because I could not figure out how to modify the jar in place. As more project adopt this standard, it would be nice to include in ANT proper. If you are interested, I can post the source code.
Possible TaskDef donation
Currently, if you want to support the JAR Services standard set forth by Sun, you have to create a file with an interface name in META-INF/services and list all the implementations. This can get to become a problem if we are adding and removing classes, and we forget to update this hand maintained file. I wrote an ANT task that will scan an existing JAR, and find all the classes that implement the specified interfaces. The task verifies that the supplied service name *is* in fact an interface, and then it checks every class in the JAR to see if it implements that interface. After it collects all this information it adds a new entry for each interface, with the list of implementations for each service. For now it needs to use an input jar and an output jar because I could not figure out how to modify the jar in place. As more project adopt this standard, it would be nice to include in ANT proper. If you are interested, I can post the source code.
