Support java-main arguments

Glyn Normington · Glyn Normington · commit 07908d659bfa · 2013-07-01T09:55:30.000+01:00
Add support for command line arguments to the java-main container.

Improve the way java-main constructs the return value of release so
that extraneoous spaces are not added.

Document arguments configuration parameter and improve the layout of
the java-main documentation.

[#52116083]
diff --git a/docs/container-java-main.md b/docs/container-java-main.md
@@ -1,5 +1,9 @@
 # Java Main Class Container
-The Java Main Class Container allows applications that provide a class with a `main()` method in it to be run.  These applications are run with a command that looks like `./java/bin/java -cp . com.gopivotal.SampleClass`.
+The Java Main Class Container allows an application that provides a class with a `main()` method to be run.  The application is executed with a command of the form:
+
+    ./java/bin/java -cp . com.gopivotal.SampleClass
+
+Command line arguments may optionally be configured.
 
 <table>
   <tr>
@@ -18,6 +22,7 @@ The container can be configured by modifying the [`config/main.yml`][main_yml] f
 
 | Name | Description
 | ---- | -----------
+| `arguments` | Optional command line arguments to be passed to the Java main class.
 | `java_main_class` | The Java class name to run. Values containing whitespace are rejected with an error, but all others values appear without modification on the Java command line.  If not specified, the Java Manifest value of `Main-Class` is used.
 
 
diff --git a/lib/java_buildpack/container/main.rb b/lib/java_buildpack/container/main.rb
@@ -56,19 +56,21 @@ def compile
     #
     # @return [String] the command to run the application.
     def release
-      "#{@java_home}/bin/java -cp . #{java_opts} #{main_class}"
+      "#{@java_home}/bin/java -cp .#{java_opts}#{space main_class}#{arguments}"
     end
 
     private
 
-    CONFIGURATION_PROPERTY = 'java_main_class'.freeze
+    MAIN_CLASS_PROPERTY = 'java_main_class'.freeze
+
+    ARGUMENTS_PROPERTY = 'arguments'.freeze
 
     CONTAINER_NAME = 'java-main'.freeze
 
     MANIFEST_PROPERTY = 'Main-Class'.freeze
 
     def java_opts
-      @java_opts.compact.sort.join(' ')
+      space @java_opts.compact.sort.join(' ')
     end
 
     def manifest
@@ -78,7 +80,15 @@ def manifest
     end
 
     def main_class
-      @configuration[CONFIGURATION_PROPERTY] || manifest[MANIFEST_PROPERTY]
+      @configuration[MAIN_CLASS_PROPERTY] || manifest[MANIFEST_PROPERTY]
+    end
+
+    def arguments
+      space @configuration[ARGUMENTS_PROPERTY]
+    end
+
+    def space(value)
+      value.nil? || value == '' ? '' : ' ' + value
     end
 
   end
diff --git a/spec/java_buildpack/container/main_spec.rb b/spec/java_buildpack/container/main_spec.rb
@@ -60,6 +60,17 @@ module JavaBuildpack::Container
 
       expect(command).to eq('test-java-home/bin/java -cp . test-opt-1 test-opt-2 test-java-main-class')
     end
+
+    it 'should return command line arguments when they are specified' do
+      command = Main.new(
+        :java_home => 'test-java-home',
+        :java_opts => [],
+        :configuration => { 'java_main_class' => 'test-java-main-class',
+                            'arguments' => 'some arguments'
+        }).release
+
+      expect(command).to eq('test-java-home/bin/java -cp . test-java-main-class some arguments')
+    end
   end
 
 end
