Iterable Immutable List Assignment

Code To Implement

DefaultImmutableList

class:	DefaultImmutableList.java
methods:	head tail isEmpty iterator
package:	immutable.list.assignment
source folder:	src/main/java

Lists

Lists is a class which holds a number of static methods. As we know, in the Kingdom of Nouns, Verbs must always have an escort.

The first two static methods nil and cons will each call a constructor of the DefaultImmutableList class. The third method brackets will use nil and cons to build up the desired ImmutableList.

class:	Lists.java
methods:	nil cons brackets
package:	immutable.list.assignment
source folder:	src/main/java

nil

public static <E> ImmutableList<E> nil()

Analogous to the SML List nil constructor.

Note: often SML programs use empty brackets [] instead of nil.

cons

public static <E> ImmutableList<E> cons(E head, ImmutableList<E> tail)

Analogous to the SML List :: constructor.

brackets

@SafeVarargs
public static <E> ImmutableList<E> brackets(E... elements)

brackets accepts variable length arguments as specified by the ... syntax. When implementing the brackets method you can treat elements as an array. Combining generics and varargs can be problematic if the implementation lets the E[] escape since it will actually be an Object[]. The [@SafeVarargs] annotation indicates a promise that you will rely only on the elements of the array being of type E. This should not be a problem.

Test

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