Difference between revisions of "Iterable Immutable List Assignment"
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<nowiki>ImmutableList<Char> letters = Lists.brackets('A', 'B', 'C'); | <nowiki>ImmutableList<Char> letters = Lists.brackets('A', 'B', 'C'); | ||
Iterator<Char> iter = letters.iterator(); | Iterator<Char> iter = letters.iterator(); | ||
− | char a = iter.next(); </nowiki> | + | if(iter.hasNext()) { |
− | + | char a = iter.next(); </nowiki> | |
+ | } | ||
[[File:ImmutableList_iterator_next.svg|600px]] | [[File:ImmutableList_iterator_next.svg|600px]] | ||
Revision as of 11:53, 19 December 2020
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>
Iterator
interface java.util.Iterator<T>
Examples
Using Iterable
Implementing Iterable
DoubleRange
ArrayIterable
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');
Initial Iterator State
ImmutableList<Char> letters = Lists.brackets('A', 'B', 'C'); Iterator<Char> iter = letters.iterator();
State after next()
ImmutableList<Char> letters = Lists.brackets('A', 'B', 'C'); Iterator<Char> iter = letters.iterator(); if(iter.hasNext()) { char a = iter.next();
State after next() next()
ImmutableList<Char> letters = Lists.brackets('A', 'B', 'C'); Iterator<Char> iter = letters.iterator(); char a = iter.next(); char b = iter.next();
State after next() next() next()
ImmutableList<Char> letters = Lists.brackets('A', 'B', 'C'); Iterator<Char> iter = letters.iterator(); char a = iter.next(); char b = iter.next(); char c = iter.next();
Code To Implement
enum EmptyImmutableList
class: | EmptyImmutableList.java | ![]() |
methods: | iterator | |
package: | immutable.list.assignment | |
source folder: | src/main/java |
iterator()
return an Iterator for the EmptyImmutableList.
Question to ask yourself: Does an iterator for an EmptyImmutableList ever have a next?
class NonEmptyImmutableList
class: | NonEmptyImmutableList.java | ![]() |
methods: | iterator | |
package: | immutable.list.assignment | |
source folder: | src/main/java |
iterator()
return an 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:
NonEmptyImmutableList.this
Test
class: | IterableAssignmentTestSuite.java | ![]() |
package: | immutable.list.assignment | |
source folder: | src/test/java |