Java Reference
In-Depth Information
{
System.out.print(title+" ");
for (String s: ls)
System.out.print(s+" ");
System.out.println();
}
}
Thisapplicationdemonstratesthateachsuccessive
add()
methodcallmustincrease
itsindexby2toaccountforthepreviouslyaddedelementwhenaddinglongerweekday
namestothelist.Italsoshowsyouhowtooutputalistinreverseorder:returnalistiter-
atorwithitscursorinitializedpasttheendofthelistandrepeatedlycall
previous()
.
When you run this application, it generates the following output:
ls: Sun Mon Tue Wed Thu Fri Sat
ls: Sun Sunday Mon Monday Tue Tuesday Wed Wednesday Thu
Thursday Fri Friday Sat Saturday
Saturday Sat Friday Fri Thursday Thu Wednesday Wed Tuesday
Tue Monday Mon Sunday Sun
Set
A
set
isacollectionthatcontainsnoduplicateelements.Inotherwords,asetcontains
nopairofelements
e1
and
e2
suchthat
e1
.equals(
e2
)
returnstrue.Furthermore,a
setcancontainatmostonenullelement.Setsaredescribedbythe
Set
interface,whose
generic type is
Set<E>
.
Set
extends
Collection
and redeclares its inherited methods, for convenience
and also to add stipulations to the contracts for
add()
,
equals()
, and
hashCode()
,toaddresshowtheybehaveinasetcontext.Also,
Set
'sdocumentation
statesthatallconstructorsofimplementationclassesmustcreatesetsthatcontainnodu-
plicate elements.
Set
does not introduce new methods.
TreeSet
The
TreeSet
classprovidesasetimplementationthatisbasedonatreedatastructure.
As a result, elements are stored in sorted order. However, accessing these elements is
