Class Seq.SeqIterator

java.lang.Object
  Seq.SeqIterator

All Implemented Interfaces:

java.util.Iterator

Enclosing class:

Seq<T>

public class Seq.SeqIterator
extends java.lang.Object
implements java.util.Iterator

An iterator class capable of mutating the sequence. See the state of the Seq class.

Method Summary

int	count() Counts the elements already returned by next().
boolean	hasNext() For use with next().
T	next() Returns the next element in the iteration.
Seq<T>	peek() Shows the sequence yet to be iterated over.
void	remove() not implemented
void	replaceRecent(T first) Alters the element of the sequence that was most recently returned by next()
void	splice(Seq<T> addMe) Splices a sequence into the new sequence--between the subsequences that would be separated with split().
Seq.SeqIterator	split() Splits off the part of the sequence that peek() shows.

Methods inherited from class java.lang.Object

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

Method Detail

next

public T next()

Returns the next element in the iteration. Calling this method repeatedly until the hasNext() method returns false will return each element in the sequence exactly once. Does not change the sequence.

Specified by:

next in interface java.util.Iterator

Returns:

the next element in the sequence

hasNext

public boolean hasNext()

For use with next(). Does not change the underlying sequence.

Specified by:

hasNext in interface java.util.Iterator

Returns:

a boolean, true iff next() will provide another element

remove

public void remove()

not implemented

Specified by:

remove in interface java.util.Iterator

count

public int count()

Counts the elements already returned by next().

Returns:

a count of the elements already returned by next()

replaceRecent

public void replaceRecent(T first)

Alters the element of the sequence that was most recently returned by next()

Parameters:

first - the value to replace the count() position in the sequence

peek

public Seq<T> peek()

Shows the sequence yet to be iterated over. The returned sequence is not a copy and includes only elements as yet unseen of the sequence the iterator is passing over.

Returns:

returns a sequence, namely that sequence yet to be iterated over.

split

public Seq.SeqIterator split()

Splits off the part of the sequence that peek() shows.

The original sequence will end with the most recent element to be returned by next. The current iterator becomes a newly created iterator for the sequence that is split off which is to say the sequence which peek() would show.

When the cursor is iterating over an empty sequence, the split method has no effect.

Returns:

A new iterator that has passed over the shortened original sequence. (Valuable for splicing other sequences to the end of that sequence.)

splice

public void splice(Seq<T> addMe)

Splices a sequence into the new sequence--between the subsequences that would be separated with split().

The original sequence is increased in length by the length of the sequence being spliced in. Splicing occurs just before the element, if any, that next() would return next. That element will still be returned by next() after the splicing.

The sequence to be spliced in is also changed because the sequence you would get with peek() is added to the end of it.

The splice method still works if either of the two sequences involved is empty.

Parameters:

addMe - the sequence to be splice in

Gotcha: When you splice to the front of a sequence, you must then use addMe to represent the whole sequence.