# Recursively populate JTree, using list of list

184
May 11, 2019, at 8:50 PM

I want to implement a method optimization of process, I reduced this process simple (multiplication and division) like a Tree shown.

The Bottom and Bold Rectangles (the online tool don't let me change the color) represent the total multiplication between N Numerators and D Denominators of each list.

Now, I was creating list of list in Java, in order to calculate the total cost of each list (process).

My first step was create a class...

``````public class Pair {
private int num;
private int den;
public Pair(int num, int den) {
this.num = num;
this.den = den;
}
public int getNum() {
return num;
}
public void setNum(int num) {
this.num = num;
}
public int getDen() {
return den;
}
public void setDen(int den) {
this.den = den;
}
@Override
public String toString() {
return "Pair{" + "num=" + num + ", den=" + den + '}';
}
}
``````

The second step was...

public class TestPair {

`````` public static void main(String... args) {
ArrayList<ArrayList<Pair>> listOfListPair = new ArrayList<>();
new Pair[]{new Pair(1, 1), new Pair(3, 1), new Pair(1, 2)}));
new Pair[]{new Pair(1, 1), new Pair(3, 1), new Pair(3, 1)}));
new Pair[]{new Pair(1, 1), new Pair(3, 1), new Pair(2, 1)}));

new Pair[]{new Pair(1, 1), new Pair(11, 2), new Pair(1, 2)}));
new Pair[]{new Pair(1, 1), new Pair(11, 2), new Pair(13, 3)}));

new Pair[]{new Pair(1, 1), new Pair(1, 7), new Pair(1, 2)}));
new Pair[]{new Pair(1, 1), new Pair(1, 7), new Pair(2, 1), new Pair(2, 1)}));
new Pair[]{new Pair(1, 1), new Pair(1, 7), new Pair(2, 1), new Pair(3, 1)}));
new Pair[]{new Pair(1, 1), new Pair(1, 7), new Pair(2, 1), new Pair(5, 1)}));
new Pair[]{new Pair(1, 1), new Pair(1, 7), new Pair(2, 1), new Pair(2, 7)}));
javax.swing.JTree myTree = new javax.swing.JTree();
listOfListPair.stream().forEachOrdered(listPair -> {
//HOW POPULATE THE myTree?
});
}
``````

}

Some clue for recursively populate my tree?,

``````public class TestPair {
public static void main(String... args) {
List<List<Pair>> listOfListPair = new ArrayList<>();
new Pair[]{new Pair(1, 1), new Pair(3, 1), new Pair(1, 2)}));
new Pair[]{new Pair(1, 1), new Pair(3, 1), new Pair(3, 1)}));
new Pair[]{new Pair(1, 1), new Pair(3, 1), new Pair(2, 1)}));
new Pair[]{new Pair(1, 1), new Pair(11, 2), new Pair(1, 2)}));
new Pair[]{new Pair(1, 1), new Pair(11, 2), new Pair(13, 3)}));
new Pair[]{new Pair(1, 1), new Pair(1, 7), new Pair(1, 2)}));
new Pair[]{new Pair(1, 1), new Pair(1, 7), new Pair(2, 1), new Pair(2, 1)}));
new Pair[]{new Pair(1, 1), new Pair(1, 7), new Pair(2, 1), new Pair(3, 1)}));
new Pair[]{new Pair(1, 1), new Pair(1, 7), new Pair(2, 1), new Pair(5, 1)}));
new Pair[]{new Pair(1, 1), new Pair(1, 7), new Pair(2, 1), new Pair(2, 7)}));
final JTree tree = new JTree();
tree.setRootVisible(false);
removeAllTreeNodes(tree);
listOfListPair.stream().forEachOrdered(listPair -> {
});
JFrame frame = new JFrame("Optimization Pair");
JScrollPane scrollPane = new JScrollPane();
scrollPane.setViewportView(tree);
frame.pack();
frame.setSize(new Dimension(600, 600));
frame.setVisible(true);
}
private static void addPairToTree(JTree tree, List<Pair> listPair) {
try {
DefaultTreeModel treeModel = ((DefaultTreeModel) tree.getModel());
DefaultMutableTreeNode rootTreeNode = (DefaultMutableTreeNode) treeModel.getRoot();
DefaultMutableTreeNode pairTreeNode = rootTreeNode;
final Pair leafPair = new Pair(1, 1);
for (Pair pair : listPair) {
pairTreeNode = getDefaultMutableTreeNode(pairTreeNode, pair, true);
leafPair.setDen(leafPair.getDen() * ((Pair) pairTreeNode.getUserObject()).getDen());
leafPair.setNum(leafPair.getNum() * ((Pair) pairTreeNode.getUserObject()).getNum());
}
getDefaultMutableTreeNode(pairTreeNode, leafPair, false);
} catch (Exception e) {
throw e;
}
}
private static DefaultMutableTreeNode getDefaultMutableTreeNode(DefaultMutableTreeNode parent, Pair newChild, Boolean isLeaf) {
if (parent != null) {
DefaultMutableTreeNode child;
for (int i = 0; i < parent.getChildCount(); i++) {
child = (DefaultMutableTreeNode) parent.getChildAt(i);
if (child.toString().equals(newChild.toString())) {
return child;
}
}
child = new DefaultMutableTreeNode(newChild, isLeaf);
return child;
} else {
return null;
}
}
private static void removeAllTreeNodes(JTree tree) {
DefaultMutableTreeNode rootTreeNode = (DefaultMutableTreeNode) tree.getModel().getRoot();
if (rootTreeNode != null) {
rootTreeNode.removeAllChildren();
}
}
private static void reloadTree(JTree tree) {
DefaultTreeModel treeModel = ((DefaultTreeModel) tree.getModel());
DefaultMutableTreeNode rootTreeNode = (DefaultMutableTreeNode) treeModel.getRoot();
}
}
``````
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