我想在Java GUI中显示树,但我不知道如何.树代表连接节点的图形,如下所示：

我应该说我有自己的树类：

public class BinaryTree

{

private BinaryNode root;

public BinaryTree( )

{

root = null;

}

public BinaryTree( Object rootItem )

{

root = new BinaryNode( rootItem, null, null );

}

public BinaryTree( Object rootItem,BinaryNode a,BinaryNode b )

{

root = new BinaryNode( rootItem, a, b );

}

public int leavesCount(){

return BinaryNode.leavesCount(root);

}

public boolean equal(BinaryTree a,BinaryTree b){

return BinaryNode.equal(a.root, b.root);

}

public void printPreOrder( )

{

if( root != null )

root.printPreOrder( );

}

public void printInOrder( )

{

if( root != null )

root.printInOrder( );

}

public void printPostOrder( )

{

if( root != null )

root.printPostOrder( );

}

public void makeEmpty( )

{

root = null;

}

public boolean isEmpty( )

{

return root == null;

}

public void merge( Object rootItem, BinaryTree t1, BinaryTree t2 ) throws MergeAbrot

{

if( t1.root == t2.root && t1.root != null )

{

throw new MergeAbrot("MergeAbrot");

}

root=new BinaryNode( rootItem, t1.root, t2.root );

if( this != t1 )

t1.root = null;

if( this != t2 )

t2.root = null;

}

public int size( )

{

return BinaryNode.size( root );

}

public int height( )

{

return BinaryNode.height( root );

}

}

我只想画树.我应该怎么做？