Hi. Comments in line.
Rosen, Alex wrote:
I agree. We were thinking about adding similar functionality. It's confusing to have both <jar> and <jlink> tasks that do similar but different things - I agree that the <jlink> functionality should be moved into <jar>. Stefan seemed to disagree though:
Stefan Bodewig <[EMAIL PROTECTED]> 2000-09-11:
We shouldn't try to duplicate this functionality (adding files to existing .jar files for example) in <jar> IMHO. Let's keep <jar> the simple solution that fits most situations and point people to <jlink> in the more difficult ones.
To me, this is confusing, and it also presents problems if people want to use different features at once. E.g. what if you want to use the <war> task but also want the merging capabilities of <jlink>? And maybe some other feature of another <jar> derivative in the future? You can't do that unless the common functionality is in the base <jar> task. Stefan, what do you think?
On the other hand, you do have the problem of how exactly to combine these pieces of functionality. E.g the <jar> task now can have <prefixedfileset> children, which are just like <filesets> except that then can specify where in the target JAR the files should go. (Kind of the complement of your <jarfilter> functionality.) The question is, can I suck out the contents of a JAR file with <jarfilter> and place them in a particular subdirectory of the target JAR? If so, do we need <fileset> <prefixedfileset> <jarfilter> and <prefixedjarfilter>? The list could expand exponentially. That's why I preferred having just <fileset>, which would have the special property that it can have certain extra attributes in certain cases. Then, you could just use <fileset sourcejar="blah.jar" prefix="web-inf/classes" />.
Filtered jar files don't make sense in many (most?) contexts where filesets are used (e.g. Delete, Copy, Chmod, Move, ExecOn, Ftp, etc), so I am a little uncomfortable folding such specialized functionality into something as generic as FileSets. Also, I think it may not be a comfortable fit; I've encountered code that assumes that the items in a FileSet are individual files on the file system which is not the case with Jar entries.
Regarding a prefix for the entries, I think it would be appropriate to add a prefix attribute to jarfilter. I agree that it would be bad to add a whole new type for this.
On a different note, the doc says that "jlink ignores META-INF directories in mergefiles. Users should supply their own manifest information for the output file." How do your changes handle this? Should we leave it up to the user to exclude META-INF, or will this be error-prone? Do we need something ugly like exclude-meta-inf="false"?
We should not exclude META-INF files altogether. I think the right thing to do is to keep track of which files are added to the META-INF directory, and ignore duplicates. Arguably, this is true for all files in the Jar, not just files in the META-INF directory.
Alex
-----Original Message----- From: Don Ferguson [mailto:[EMAIL PROTECTED] Sent: Friday, December 29, 2000 6:49 PM To: [EMAIL PROTECTED] Subject: JLink vs. Jar
I have recently begun exploring ant, and have found the JLink task to be insufficient for my needs, and also, not consistent with other file based ant tasks. Specifically, JLink does not provide a mechanism for selecting a subset of a jar file via includes/excludes. It also seems to me that there is too much overlap in the functionality provided by Jar and JLink, so in my copy of the sources, I have modified the Jar task to subsume the capabilities of JLink by addition of a new data type: JarFilter. The Jar task can include both FileSets and JarFilters. A JarFilter extracts a subset of files from the jar using the same matching rules as FileSets, and includes these files in the output jar. For example, the following would create "myant.jar", including my ant classes with the standard ant.jar, but excluding JLink:
<?xml version="1.0"?>
<project name="JarExample" default="main" basedir="."> <target name="main"> <jar jarfile="myant.jar"> <fileset dir="/home/don/classes" includes="weblogic/ant/" /> <jarfilter jarfile="/ant/lib/ant.jar" includes="org/apache/"
excludes="org/apache/tools/ant/taskdefs/optional/jlink/" /> </jar> </target> </project>
I think this make the Jar task much more useful, but as I'm new to ant, I'd be curious to hear what others have to say about this approach. Comments?
-Don
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