SVN Basics

The folks at Inkscape have got a nice document on working with Subversion Repositories. Though it is Inkscape specific, but it is generic enough to be a good resource for working with all SVN repositories.

Here is the link

Representing Hierarchical Data in Java

While working on odf4j, I faced an issue where I had to deal with a set of data which had a hierarchical relationship between them. Specifically, I could generate a tree to represent the relationship between them. The next obvious task was to implement the data structure.

A easy and simple, yet inelegant solution is to implement the tree using conventional C-style approach – instead of using structures, use Java classes.

However, a better approach is to use classes in the javax.swing.tree package. These classes are actually defined for use in jTree. However, with a little bit of manipulation, you can easily use them in your own projects. The additional benefit is that you also get some ready made methods like – depth first search, breadth first search, etc. This surely makes life easier!

The following code generates the tree structure shown earlier using the class javax.swing.tree.DefaultMutableTreeNode :

public class StyleTree {
private DefaultMutableTreeNode top;

public void getStyle(String style_name) {

     //Create the nodes.
 top = new DefaultMutableTreeNode("ODT Style Families");

     createNodes(top);
 search(style_name);
 }

private void createNodes(DefaultMutableTreeNode top) {
     DefaultMutableTreeNode style_family = null;
     DefaultMutableTreeNode parent_style = null;
     DefaultMutableTreeNode style_name_1 = null;
     DefaultMutableTreeNode style_name_2 = null;
     DefaultMutableTreeNode style_name_3 = null;

     style_family = new DefaultMutableTreeNode("graphic");
     top.add(style_family);

     style_family = new DefaultMutableTreeNode("Paragraph");
     top.add(style_family);

     parent_style = new DefaultMutableTreeNode("standard");
     style_family.add(parent_style);
 
     style_name_1 = new DefaultMutableTreeNode("index");
     parent_style.add(style_name_1);
 
     style_name_2 = new DefaultMutableTreeNode("Text_20_body");
     parent_style.add(style_name_2);
 
     style_name_1 = new DefaultMutableTreeNode("P1");
     style_name_2.add(style_name_1);
 
     style_name_1 = new DefaultMutableTreeNode("P2");
     style_name_2.add(style_name_1);
 
     style_name_1 = new DefaultMutableTreeNode("Heading");
     style_name_2.add(style_name_1);
 
     style_name_1 = new DefaultMutableTreeNode("List");
     style_name_2.add(style_name_1);
 
     style_name_3 = new DefaultMutableTreeNode("caption");
     parent_style.add(style_name_3);
 
 
     style_family = new DefaultMutableTreeNode("table");
     top.add(style_family);
 
     style_family = new DefaultMutableTreeNode("table_row");
     top.add(style_family);


 }

 private void search(String item){

.
.

      }

}

}

I hope this is clear. In case of doubts, ping me back!

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