net.cscott.sdr.util
Class LL<T>

java.lang.Object
  net.cscott.sdr.util.LL<T>

All Implemented Interfaces:

Iterable<T>

public class LL<T>
extends Object
implements Iterable<T>

Persistent Linked List.

Field Summary

T	head Element at the start of the list
LL<T>	tail Remainder of the elements in the list.

Constructor Summary

LL(T head, LL<T> tail)
Add an element to the front of tail.

Method Summary

static <T> LL<T>	create(List<T> elements) Factory: create a list.
static <T> LL<T>	create(T... elements) Factory: create a list.
boolean	isEmpty() Are there any elements in this list?
Iterator<T>	iterator() Iterate over all the elements in this list from head to tail.
static <T> LL<T>	NULL() Return a new empty list.
LL<T>	pop() Remove the head of the list.
LL<T>	push(T head) Add the given element to the start of the list.
LL<T>	reverse() Return a list with elements in reverse order.
int	size() Return the number of items in this list.
List<T>	toList()
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

head

public final T head

Element at the start of the list

tail

public final LL<T> tail

Remainder of the elements in the list.

Constructor Detail

LL

public LL(T head,
          LL<T> tail)

Add an element to the front of tail.

Method Detail

create

public static <T> LL<T> create(T... elements)

Factory: create a list.

Tests:

js> l = LL.create("a","b","c","d");
[a, b, c, d]

create

public static <T> LL<T> create(List<T> elements)

Factory: create a list.

Tests:

js> l = LL.create(java.util.Arrays.asList("a","b","c","d"));
[a, b, c, d]

push

public LL<T> push(T head)

Add the given element to the start of the list.

Tests:

js> l = LL.create("a","b","c","d");
[a, b, c, d]
js> l = l.push("e");
[e, a, b, c, d]
js> l = l.push("f");
[f, e, a, b, c, d]

pop

public LL<T> pop()

Remove the head of the list.

Tests:

js> l = LL.create("a","b","c","d");
[a, b, c, d]
js> l = l.pop();
[b, c, d]
js> l = l.pop();
[c, d]
js> l = l.pop();
[d]
js> l = l.pop();
[]

isEmpty

public boolean isEmpty()

Are there any elements in this list?

Tests:

js> l = LL.create("a","b","c","d");
[a, b, c, d]
js> l.isEmpty()
false
js> LL.NULL().isEmpty()
true

size

public int size()

Return the number of items in this list.

Tests:

js> l = LL.create("a","b","c","d");
[a, b, c, d]
js> l.size()
4
js> LL.NULL().size()
0

iterator

public Iterator<T> iterator()

Iterate over all the elements in this list from head to tail.

Specified by:

iterator in interface Iterable<T>

Tests:

js> l = LL.create("a","b","c","d");
[a, b, c, d]
js> [x for (x in Iterator(l))]
a,b,c,d
js> [x for (x in Iterator(LL.NULL()))].length
0

NULL

public static <T> LL<T> NULL()

Return a new empty list.

Tests:

js> LL.NULL();
[]
js> LL.NULL().isEmpty();
true

reverse

public LL<T> reverse()

Return a list with elements in reverse order.

Tests:

js> l = LL.create("asda","bar","foo");
[asda, bar, foo]
js> l.reverse();
[foo, bar, asda]
js> l = LL.NULL();
[]
js> l.reverse();
[]

toString

public String toString()

Overrides:

toString in class Object

toList

public List<T> toList()