Manifest attributes in build.gradle

We already inspected how default manifest looks like. Now we will program manifest attributes in build.gradle.

Add manifest attributes to "build.gradle"

Edit the file "tutorials/MyOsgiBundle/build.gradle", insert the code:

jar {
  manifest {
    instruction 'Bundle-SymbolicName', 'blabla'
    instruction 'Bundle-Name', 'hurray! hurray!'
    instruction 'Bundle-Version', '999'
    instruction 'Bundle-ManifestVersion', '22'
    instruction 'Bnd-LastModified', '9999999999999'                                    
    instruction 'Created-By', 'Dr. Who'
    instruction 'Tool', 'kekek'
    instruction 'Bundle-ClassPath', 'somefolder', 'anotherfolder'
    instruction 'Require-Bundle', 'ch.qos.logback.classic'
    instruction 'My-Attribute', 'test'
  }
}

Here we configure "manifest" property of the Jar task. Note that manifest supports interface OsgiManifest. This is because Wuff implicitly applies gradle 'osgi' plugin to the project.

Compile

Invoke on command line: gradle build.

Inspect resulting manifest

Open file "tutorials/MyOsgiPlugin/build/libs/MyOsgiPlugin-1.0.0.0.jar", open "META-INF/MANIFEST.MF", it should look like:

Manifest-Version: 1.0
Bundle-SymbolicName: MyOsgiPlugin
Bundle-Name: MyOsgiPlugin
Bundle-Version: 1.0.0.0
Bundle-ClassPath: somefolder,.,anotherfolder
Require-Bundle: org.eclipse.osgi,ch.qos.logback.classic
Bundle-ManifestVersion: 2
Bnd-LastModified: 1399560688000
My-Attribute: test
Created-By: 1.8.0_05 (Oracle Corporation)
Tool: Bnd-2.1.0.20130426-122213

As we see, Wuff overwritten our values for attributes "Bundle-SymbolicName", "Bundle-Name", "Bundle-Version", "Bundle-ManifestVersion", "Bnd-LastModified", "Created-By", "Tool". This is caused by the sequence of manifest merge: resulting-manifest << build.gradle << default-manifest.

The attributes "Require-Bundle" and "Bundle-ClassPath" were merged, not overwritten. In the result above, "Require-Bundle" contains two values: "ch.qos.logback.classic" comes from "build.gradle" and "org.eclipse.osgi" comes from default manifest. Also we see, that "Bundle-ClassPath" contains three values: "somefolder" and "anotherfolder" come from "build.gradle", "." comes from default manifest.

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The example code for this page: examples/Manifest-2.

Next page: Manifest attributes in MANIFEST.MF.