structure
Class BTPostorderIterator

java.lang.Object
  |
  +--structure.AbstractIterator
        |
        +--structure.BTPostorderIterator

All Implemented Interfaces:

Enumeration, Iterator

class BTPostorderIterator

extends AbstractIterator

This class implements a post-order traversal of a binary tree. This iterator considers every node after its non-trivial descendants.

Example usage:

      BinaryTree t = new BinaryTree();
      // ...tree is grown
      Iterator ti = t.postorderIterator();
      while (ti.hasNext())
      {
          System.out.println(ti.next());
      }
      ti.reset();
      while (ti.hasNext())
      { .... }
 

See Also:

BinaryTree#PostorderElements

Field Summary

protected BinaryTree	root The root of the tree currently being traversed.
protected Stack	todo The stack the maintains the state of the iterator.

Constructor Summary

BTPostorderIterator(BinaryTree root)
Construct an iterator to traverse subtree rooted at root in post-order.

Method Summary

Object	get() Return the value of the current node.
boolean	hasNext() Return true iff more nodes are to be considered in traversal.
Object	next() Return current value and increment iterator.
void	reset() Reset the iterator to the first node of the traversal.

Methods inherited from class structure.AbstractIterator

hasMoreElements, nextElement, remove, value

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait

Field Detail

root

protected BinaryTree root

The root of the tree currently being traversed.

todo

protected Stack todo

The stack the maintains the state of the iterator. Elements of the stack are nodes whose descendants are still being considered.

Constructor Detail

BTPostorderIterator

public BTPostorderIterator(BinaryTree root)

Construct an iterator to traverse subtree rooted at root in post-order.

Parameters:

root - The root of the subtree to be traversed.

Method Detail

reset

public void reset()

Reset the iterator to the first node of the traversal.

Overrides:

reset in class AbstractIterator

Postcondition:

Resets the iterator to retraverse

hasNext

public boolean hasNext()

Return true iff more nodes are to be considered in traversal.

Overrides:

hasNext in class AbstractIterator

Postcondition:

Returns true iff iterator is not finished

Returns:

True iff more nodes are to be considered in traversal.

get

public Object get()

Return the value of the current node.

Overrides:

get in class AbstractIterator

Precondition:

hasNext()

Postcondition:

returns reference to current value

Returns:

The value referenced by current node.

next

public Object next()

Return current value and increment iterator.

Overrides:

next in class AbstractIterator

Precondition:

hasNext();

Postcondition:

returns current value, increments iterator

Returns:

The value currently considered by iterator, increment.