Manifest Reader for Ant Tool

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Introduction

This article presents a simple but quite useful ant task for reading MANIFEST.MF file contained in a jar and selectively print it's 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 it's existence. This can be very easily done by putting follwing 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 produde 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

• attribute
  One attribute for the manifest file. Those attributes that are not nested into a section will be added to the "Main" section.
  

  Attribute	Description	Required
  name	the name of the attribute as defined in manifest file.	Yes
  value	the label text to be used while printing the manifest attribute value.	Yes

• section
  A manifest section - you can nest attribute elements into sections.
  

  Attribute	Description	Required
  name	the name of the section as defined in manifest file.	No, if omitted it will be assumed to be the main section.

Conclusion

Ant tool does provide a task for manifest file creation. This task now compltes 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 stand alone java service is started by using Ant tool. This can quickly help in determining whether the user of your application is using correct jar file or not.

History

• March 03, 2006 - First release.