craterdog.core

Class Iterator<E>

java.lang.Object

craterdog.core.Iterator<E>

Type Parameters:

E - The type of the element being iterated over.

All Implemented Interfaces:

Iterator<E>

Direct Known Subclasses:

Manipulator

public abstract class Iterator<E>
extends Object
implements Iterator<E>

This abstract class defines a framework for each concrete iterator class that allows iteration over a sequence's elements. The iterator points at the slots on either side of the elements in the sequence:

            [element 1]   [element 2]   [element 3]  ...  [element N]
          ^             ^             ^             ^   ^             ^
       at start                                                    at end
 

Author:

Derk Norton

Constructor Summary

Constructors

Constructor and Description
Iterator()

Method Summary

Modifier and Type	Method and Description
abstract E	getNext() This method returns the element after the slot where the iterator is currently pointing.
abstract E	getPrevious() This method returns the element before the slot where the iterator is currently pointing.
abstract boolean	hasNext() This method determines if the iterator is currently pointing at a slot just before an element in this sequence.
abstract boolean	hasPrevious() This method determines if the iterator is currently pointing at a slot just after an element in this sequence.
E	next()
void	remove()
abstract void	toEnd() This method moves the iterator to the slot just past the last element in this sequence.
abstract void	toIndex(int index) This method moves the iterator to the slot just before the specified index.
abstract void	toStart() This method moves the iterator to just before the first element in this sequence.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Detail

Iterator

public Iterator()

Method Detail

toStart

public abstract void toStart()

This method moves the iterator to just before the first element in this sequence. The next element to be returned will the first element in this sequence.

toIndex

public abstract void toIndex(int index)

This method moves the iterator to the slot just before the specified index. The next element to be returned will then be the element with that index. The valid values for the index are in the range [1..size] where size is the number of elements in the sequence. Notice that this interface uses ordinal based indexing instead of zero-based indexing (come on, its time to get out of the 1970s!).

Parameters:

index - The index of the element to be returned next by the iterator.

toEnd

public abstract void toEnd()

This method moves the iterator to the slot just past the last element in this sequence. There is no next element that can be returned from this position.

hasPrevious

public abstract boolean hasPrevious()

This method determines if the iterator is currently pointing at a slot just after an element in this sequence. If the iterator is at the start of the sequence this method will return false.

Returns:

Whether or not there is an element just before the current position of the iterator.

getPrevious

public abstract E getPrevious()

This method returns the element before the slot where the iterator is currently pointing. If the iterator is at the start of this sequence an exception is thrown.

Returns:

The previous element in this sequence.

hasNext

public abstract boolean hasNext()

This method determines if the iterator is currently pointing at a slot just before an element in this sequence. If the iterator is at the end of the sequence this method will return false.

Specified by:

hasNext in interface Iterator<E>

Returns:

Whether or not there is an element just after the current position of the iterator.

getNext

public abstract E getNext()

This method returns the element after the slot where the iterator is currently pointing. If the iterator is at the end of this sequence an exception is thrown.

Returns:

The next element in this sequence.

next

public final E next()

Specified by:

next in interface Iterator<E>

remove

public void remove()

Specified by:

remove in interface Iterator<E>