Iterable Immutable List Assignment

Studio To Revisit

In this studio we will complete the DefaultImmutableList implementation from the ImmutableList studio.

ImmutableList

The ImmutableList interface extends Iterable which has one method: iterator().

public interface ImmutableList<E> extends Iterable<E> {
	E head();
	ImmutableList<E> tail();
	boolean isEmpty();
}

Iterable

interface java.lang.Iterable<T>

1. Iterator<T> iterator()

Iterator

interface java.util.Iterator<T>

1. boolean hasNext()
2. T next()

Example

class:	IterableImmutableListExample.java
package:	immutable.list.example
source folder:	src/main/java

The code:

ImmutableList<Integer> numbers = Lists.brackets(4, 66, 99);
for (Integer i : numbers) {
	System.out.println(i);
}

produces:

4
66
99

Diagrams

ImmutableList

ImmutableList<Char> letters = Lists.brackets('A', 'B', 'C'); <nowiki>

[[File:ImmutableList_letters.svg|600px]]

==iterator()==

 <nowiki>ImmutableList<Char> letters = Lists.brackets('A', 'B', 'C');
Iterator<Char> iter = letters.iterator() <nowiki>

[[File:ImmutableList_iterator.svg|600px]]

==next()==

[[File:ImmutableList_iterator_next.svg|600px]]

==next() next()==

[[File:ImmutableList_iterator_next_next.svg|600px]]

==next() next() next()==
[[File:ImmutableList iterator next next next.svg|600px]]

=Code To Implement=
==enum EmptyImmutableList==
{{JavaToImplement|EmptyImmutableList|iterator|immutable.list.assignment}}
===iterator()===
return an [https://docs.oracle.com/javase/8/docs/api/java/util/Iterator.html Iterator] for the EmptyImmutableList.

Question to ask yourself: Does an iterator for an EmptyImmutableList ever have a next?

==class NonEmptyImmutableList==
{{JavaToImplement|NonEmptyImmutableList|iterator|immutable.list.assignment}}
===iterator()===
return an [https://docs.oracle.com/javase/8/docs/api/java/util/Iterator.html Iterator] for this instance of NonEmptyImmutableList.

Note: If you are within an anonymous inner class, the way to get the outer class's this instance is to qualify it with the out class identifier.  For example:

 <nowiki>NonEmptyImmutableList.this

Test

class:	IterableAssignmentTestSuite.java
package:	immutable.list.assignment
source folder:	src/test/java

class:	ImmutableListIteratorMethodTestSuite.java
package:	immutable.list.assignment
source folder:	src/test/java