Introduction
This article presents a simple but quite useful Ant task for reading MANIFEST.MF file contained in a jar and selectively printing its content.
MANIFEST.MF
MANIFEST.MF file is a simple text file containing one or more sections and information related to each section in name value pair format. The major purpose of having this file is that it allows you to define extension and package related data.
Task Usage
To be able to use this task, you need to inform Ant about its existence. This can be very easily done by putting the following script in your Ant build file.
<typedef resource="com/freeware/anttasks/antlib.xml">
<classpath path="${basedir}/antcontrib/mfprinter-1.0.2.jar" />
</typedef>
Once this is done, you are ready to use this task in your build script. The following Ant script snippet shows a typical usage of this task.
<target name="printinfo" description="Print application details!">
<manifestreader srcfile="${basedir}/antcontrib/mfprinter-1.0.2.jar">
<attribute name="Build-Date" value="Built On :"/>
<section name="com/freeware/anttasks">
<attribute name="Implementation-Title" value="Product Name :"/>
<attribute name="Implementation-Version" value="Product Version :"/>
<attribute name="Implementation-Vendor" value="Copyright :"/>
</section>
</manifestreader>
</target>
The above code snippet will produce the following output:
Buildfile: testtask.xml
test:
[manifestreader] Built On : March 3 2006 at 11:41 AM
[manifestreader] Product Name : Manifest Printer
[manifestreader] Product Version : 1.0.2
[manifestreader] Copyright : Khan Information Systems
BUILD SUCCESSFUL
Total time: 0 seconds
Task Parameters
Attribute |
Description |
Required |
srcfile |
The full path and name of the jar file whose manifest is to be read |
Yes |
Nested Elements
Conclusion
Ant tool does provide a task for manifest file creation. This task now completes the manifest task by providing the read capability. The main motivation behind development of this task was to be able to display certain useful fields from manifest file in situations where the standalone Java service is started by using Ant tool. This can quickly help in determining whether the user of your application is using the correct jar file or not.
History
- March 03, 2006 - First release