Make prepare mojo subclassable

git-svn-id: https://svn.apache.org/repos/asf/sling/trunk@1630197 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/sling/maven/slingstart/PreparePackageMojo.java b/src/main/java/org/apache/sling/maven/slingstart/PreparePackageMojo.java
index e29620f..e1e4725 100644
--- a/src/main/java/org/apache/sling/maven/slingstart/PreparePackageMojo.java
+++ b/src/main/java/org/apache/sling/maven/slingstart/PreparePackageMojo.java
@@ -97,6 +97,10 @@
         this.prepareWebapp(model);
     }
 
+    protected File getStandaloneOutputDirectory() {
+        return new File(this.project.getBuild().getOutputDirectory());
+    }
+
     /**
      * Prepare the global map for the artifacts.
      */
@@ -115,7 +119,7 @@
         this.project.setContextValue(BuildConstants.CONTEXT_STANDALONE, contentsMap);
 
         // unpack base artifact and create settings
-        final File outputDir = new File(this.project.getBuild().getOutputDirectory());
+        final File outputDir = getStandaloneOutputDirectory();
         unpackBaseArtifact(model, outputDir, ModelConstants.RUN_MODE_STANDALONE);
         this.buildSettings(model, ModelConstants.RUN_MODE_STANDALONE, outputDir);
         this.buildBootstrapFile(model, ModelConstants.RUN_MODE_STANDALONE, outputDir);