Merge pull request #237 from manu4linux/issue-236

Linker default dependency Lib Order #236

pom.xml

@@ -189,6 +189,11 @@
       <artifactId>maven-common-artifact-filters</artifactId>
       <version>1.4</version>
     </dependency>
+    <dependency>
+      <groupId>org.apache.maven.shared</groupId>
+      <artifactId>maven-dependency-tree</artifactId>
+      <version>2.2</version>
+    </dependency>
     <dependency>
       <groupId>org.apache.maven.surefire</groupId>
       <artifactId>surefire-api</artifactId>

src/main/java/com/github/maven_nar/AbstractDependencyMojo.java

@@ -49,6 +49,11 @@
 import org.codehaus.plexus.archiver.manager.ArchiverManager;
 import org.codehaus.plexus.util.StringUtils;
 
+import org.apache.maven.shared.dependency.graph.DependencyGraphBuilder;
+import org.apache.maven.shared.dependency.graph.DependencyGraphBuilderException;
+import org.apache.maven.shared.dependency.graph.DependencyNode;
+import org.apache.maven.artifact.resolver.filter.ArtifactFilter;
+
 /**
  * @author Mark Donszelmann
  */
@@ -101,6 +106,130 @@ public abstract class AbstractDependencyMojo extends AbstractNarMojo {
   @Parameter(property = "includeGroupIds", defaultValue = "")
   protected String includeGroupIds;
 
+  /**
+   * The computed dependency tree root node of the Maven project.
+   */
+  protected  DependencyNode rootNode;
+
+  /**
+   * The dependency tree builder to use.
+   */
+  @Component( hint = "default" )
+  protected  DependencyGraphBuilder dependencyGraphBuilder;
+
+  /**
+   * The computed dependency tree root node of the Maven project.
+   */
+  private List<DependencyNode> LevelOrderList = new ArrayList<DependencyNode>();
+
+  /**
+   * Serializes the dependency tree of current maven project to a string of comma separated list
+   * of groupId:artifactId traversing nodes in Level-Order way (also called BFS algorithm)
+   *
+   * @return Dependency tree string of comma separated list
+   * of groupId:artifactId
+   */
+  protected String dependencyTreeOrderStr()
+  {
+    String depLevelOrderStr = "";
+    DependencyNode libTreeRootNode;
+
+    try {
+      libTreeRootNode = getRootNodeDependecyTree();
+    } catch (MojoExecutionException exception) {
+      this.getLog().warn("linker Nar Default DependencyLibOrder is not used");
+      return depLevelOrderStr;
+    }
+
+    final List<DependencyNode> NodeList = depLevelOrderList(libTreeRootNode);
+
+    this.getLog().debug("{");
+    this.getLog().debug("Dependency Lib Order to be used::");
+
+    for (DependencyNode node : NodeList) {
+
+      if ( node != null ) {
+        String[] nodestring = node.toNodeString().split(":");
+        String usestring = nodestring[0] + ":" + nodestring[1];
+
+        this.getLog().debug(usestring);
+
+        if (!depLevelOrderStr.isEmpty()){
+          depLevelOrderStr= depLevelOrderStr + "," + usestring;
+        }else{
+          depLevelOrderStr= usestring;
+        }
+
+      }
+    }
+
+    this.getLog().debug("}");
+
+    return depLevelOrderStr;
+  }
+
+  /**
+   * Get List of Nodes of Dependency tree serialised by traversing nodes
+   * in Level-Order way (also called BFS algorithm)
+   *
+   * @param rootNode root node of the project Dependency tree
+   * @return the dependency tree string of comma separated list
+   * of groupId:artifactId
+   */
+  private List<DependencyNode> depLevelOrderList(DependencyNode rootNode )
+  {
+
+    List<DependencyNode> NodeChildList = rootNode.getChildren();
+    //LevelOrderList.add(rootNode);
+
+    while (!NodeChildList.isEmpty()) {
+      NodeChildList = levelTraverseTreeList(NodeChildList);
+    }
+
+    return this.LevelOrderList;
+  }
+
+  /**
+   * helper function for traversing nodes
+   * in Level-Order way (also called BFS algorithm)
+   */
+  private List<DependencyNode> levelTraverseTreeList(List<DependencyNode>  NodeList )
+  {
+    this.LevelOrderList.addAll(NodeList);
+    List<DependencyNode> NodeChildList = new ArrayList<DependencyNode>();
+    for (DependencyNode node : NodeList) {
+      if ( (node != null) && (node.getChildren() != null) ) {
+        NodeChildList.addAll(node.getChildren());
+      }
+    }
+
+    return NodeChildList;
+  }
+
+
+  //idea from dependency:tree mojo
+  /**
+   * Get root node of the current Maven project Dependency tree generated by
+   * maven.shared dependency graph builder.
+   *
+   * @return root node of the project Dependency tree
+   * @throws MojoExecutionException
+   */
+  private DependencyNode getRootNodeDependecyTree() throws MojoExecutionException{
+    try {
+      ArtifactFilter artifactFilter = null;
+
+      // works for only maven 3. Use of dependency graph component not handled for maven 2
+      // as current version of NAR already requires Maven 3.x
+      rootNode = dependencyGraphBuilder.buildDependencyGraph(getMavenProject(), artifactFilter);
+
+    } catch (DependencyGraphBuilderException exception) {
+      throw new MojoExecutionException("Cannot build project dependency graph", exception);
+    }
+
+    return rootNode;
+  }
+
   /**
    * To look up Archiver/UnArchiver implementations
    */

src/main/java/com/github/maven_nar/Linker.java

@@ -159,6 +159,19 @@ public class Linker {
   @Parameter
   private String narDependencyLibOrder;
 
+  /**
+   * <p>
+   * Specifies to use Default link ordering of libraries that come from mvn dependency tree.
+   * The Default link order (generated by nar) is a Level-order tree traversing list (also called BFS) of
+   * dependency tree, given as a comma separated list of groupId:artifactId.
+   * </p>
+   * <p>
+   *  default Value is "false"
+   * </p>
+   */
+  @Parameter(defaultValue = "false")
+  private boolean narDefaultDependencyLibOrder = false;
+
   /**
    * Specify that the linker should generate an intermediate manifest based on
    * the inputs.
@@ -364,6 +377,11 @@ public final LinkerDef getLinker(final AbstractCompileMojo mojo, final CCTask ta
       }
     }
 
+    //if No user preference of dependency library link order is specified then use the Default one nar generate.
+    if ((this.narDependencyLibOrder == null) && (narDefaultDependencyLibOrder)) {
+        this.narDependencyLibOrder = mojo.dependencyTreeOrderStr();
+    }
+
     // record the preference for nar dependency library link order
     if (this.narDependencyLibOrder != null) {