ActionScript 3.0 Design Patterns

216 | Chapter 6: Composite Pattern

Executing the statements in Example 6-7 will generate the following output. The

operation( ) method traverses the tree structure recursively using a depth-first

approach, and prints the component names accordingly.

display tree

============

root

composite 1

leaf 1

leaf 2

composite 2

leaf 3

leaf 4

leaf 5

leaf 6

remove first child of the second child of root

==============================================

root

composite 1

leaf 1

leaf 2

composite 2

leaf 4

leaf 5

leaf 6

remove the second child of root

===============================

root

composite 1

leaf 1

leaf 2

leaf 6

You can easily visualize what happens to the component tree by looking at what

happens graphically in Figure 6-5.

trace("display tree");
trace("============");
root.operation( );

trace("remove first child of the second child of root");
trace("==============================================");
root.getChild(2).remove(root.getChild(2).getChild(1));
root.operation( );

trace("remove the second child of root");
trace("===============================");
root.remove(root.getChild(2));
root.operation( ); }
}
}

Example 6-7. Main.as (client code to remove nodes) (continued)