JTree custom implementation

Question

Hi All,
I have application, which eats all the memory, when I load big structure in JTree.
So I have modified following function
DefaultTreeMutableNode {
public void insert(MutableTreeNode newChild, int childIndex) {
          children = new Vector();
As follow:
DefaultTreeMutableNode {
public void insert(MutableTreeNode newChild, int childIndex) {
          children = new ArrayList(1);
As my jTree usually has single nodes. And Default constructor of Vector() creates array of 10 child nodes, for each node.
But still it uses the same memory ???
Is there any way to reduce memory usage by JTree nodes, so it can handle big strucutre.
Is there any custom implemenation is avaliable.
Thank you for your time.
Avin Patel

Answer 1

I guess ur application is a perfect candidate for a MVC implementation. In the tree there are 2 ways to do that. u can either write ur own TreeModel or u can write ur ur own TreeNode. I can help u write either of the two.
I can give u working examples from my application in each of them. U can also make the creation of the child nodes dyanamic and on a "on-demand-basis", by creating them only on the expansion of the parent nodes, as mentioned above.
The first way to do that is to override the implementation of the DefaultTreeModel class:
Plz find below an implementaion of the same:
public class GrpModuleTreeModel extends DefaultTreeModel
     TerminationPointsModel mModel = null;
     TreePanel mTreePanel;
     GrpModuleTreeModel(TerminationPointsModel model,TreePanel treePanel)
          super(null);
          mModel = model;
          mTreePanel=treePanel;
     public int getIndexOfChild(Object parent, Object child)
          if (parent.equals(mTreePanel.mParent.getParentFrame().getNEName()))
               ArrayList rackList = new ArrayList(mModel.getRacks());
               return rackList.indexOf(child);
          if (parent instanceof Rack)
//               return mModel.getSubracks(parent).size();
               ArrayList subrackList = new ArrayList(((Rack)parent).getSubracks());
               return subrackList.indexOf(child);
          if (parent instanceof Subrack)
//               return mModel.getModules(parent).size();
               ArrayList moduleList = new ArrayList(((Subrack)parent).getModules());
               return moduleList.indexOf(child);
          if (parent instanceof Module)
//               return this.mModel.getTerminationPoints(parent).size();
               ArrayList tpList = new ArrayList(((Module)parent).getTerminationPoints());
               return tpList.indexOf(child);
          if (parent instanceof TerminationPointA)
//               return this.mModel.getTerminationPoints(parent).size();
               ArrayList tpList = new ArrayList(((TerminationPointA)parent).getTerminationPointList());
               return tpList.indexOf(child);
          return -1;
     public boolean isLeaf(Object node)
          if (node instanceof TerminationPointA )
               if (node instanceof NonConfigurableCrossConnection ) return true;
               return (((TerminationPointA)node).getTerminationPointList()==null)? true: false;
//               java.util.ArrayList list=((TerminationPointA)node).getTerminationPointList();
//               System.out.println("Type====== "+((TerminationPointA)node).getTerminationPointType()+","+list);
//               if (list!=null)
//                    System.out.println("Number of nodes ========= "+list.size());
//                    for (int i = 0; i < list.size(); i++)
//                         System.out.println(list.get(i).getClass().getName());
//               return true;
          if (node instanceof Rack)
               return (((Rack)node).getSubracks()==null)? true: false;
          if (node instanceof Subrack)
               return (((Subrack)node).getModules()==null)? true: false;
          if (node instanceof Module)
               return (((Module)node).getTerminationPoints()==null)? true: false;
          return false;
     public Object getChild(Object parent, int index)
          if (parent.equals(mTreePanel.mParent.getParentFrame().getNEName()))
               ArrayList rackList = new ArrayList(mModel.getRacks());
               return (rackList!=null)? rackList.get(index):null;
          if (parent instanceof Rack)
//               return mModel.getSubracks(parent).size();
               ArrayList subrackList = new ArrayList(((Rack)parent).getSubracks());
               return (subrackList!=null? subrackList.get(index):null);
          if (parent instanceof Subrack)
//               return mModel.getModules(parent).size();
               ArrayList moduleList = new ArrayList(((Subrack)parent).getModules());
               return moduleList!=null? moduleList.get(index):null;
          if (parent instanceof Module)
//               return this.mModel.getTerminationPoints(parent).size();
               ArrayList tpList = new ArrayList(((Module)parent).getTerminationPoints());
               return tpList!=null? tpList.get(index):null;
          if (parent instanceof TerminationPointA)
//               return this.mModel.getTerminationPoints(parent).size();
               ArrayList tpList = new ArrayList(((TerminationPointA)parent).getTerminationPointList());
               return tpList.get(index);
          return null;
     public int getChildCount(Object parent)
          if (parent ==null)
               return -1;
          if (parent.equals(mTreePanel.mParent.getParentFrame().getNEName()))
               return mModel.getRacks()!=null ? mModel.getRacks().size() : -1;
          if (parent instanceof Rack)
//               return mModel.getSubracks(parent).size();
               return ((Rack)parent).getSubracks()!=null ? ((Rack)parent).getSubracks().size() : -1;
          if (parent instanceof Subrack)
//               return mModel.getModules(parent).size();
               return ((Subrack)parent).getModules()!= null? ((Subrack)parent).getModules().size() : -1;
          if (parent instanceof Module)
//               return this.mModel.getTerminationPoints(parent).size();
               return ((Module)parent).getTerminationPoints() != null ? ((Module)parent).getTerminationPoints().size(): -1;
          if (parent instanceof TerminationPointA)
//               return this.mModel.getTerminationPoints(parent).size();
               return ((TerminationPointA)parent).getTerminationPointList()!= null ? ((TerminationPointA)parent).getTerminationPointList().size(): -1;
          return -1;
     public Object getRoot()
          return mTreePanel.mParent.getParentFrame().getNEName();
IF this does'nt suffice then I can tell u another way by which u can create ur own TreeNode.
BR
Mohit