Java Reference
In-Depth Information
4. Modify the
logging
package so that
Logger
's
connect()
method
throws
CannotConnectException
when it cannot connect to its log-
ging destination, and the other two methods each throw
NotConnec-
tedException
when
connect()
wasnotcalledorwhenitthrew
Can-
notConnectException
. Modify
TestLogger
to respond appropri-
atelytothrown
CannotConnectException
and
NotConnectedEx-
ception
objects.
5. ContinuingfromExercise3,useanassertiontoverifytheclassinvariantthat
the transformation matrix is initialized to the identity matrix before
G2D
's
constructor ends.
6. Declare a
ToDo
marker annotation type that annotates only type elements,
and that also uses the default retention policy.
annotation type (with appropriate
@Target
and
@Retention
annota-
isEmpty()
methods(itcouldalsodeclarean
isFull()
methodbutthat
method is not necessary in this exercise),
push()
must throw a
Stack-
FullException
instancewhenthestackisfull,and
pop()
mustthrow
a
StackEmptyException
instancewhenthestackisempty.(Youmust
create your own
StackFullException
and
StackEmptyExcep-
tion
helperclassesbecausetheyarenotprovidedforyouinJava'sstandard
classlibrary.)Declareasimilar
main()
method,andinserttwoassertions
intothismethodthatvalidateyourassumptionsaboutthestackbeingempty
immediatelyafterbeingcreatedandimmediatelyafterpoppingthelastele-
ment.
9. Declare a
Compass
enum with
NORTH
,
SOUTH
,
EAST
, and
WEST
mem-
bers. Declare a
UseCompass
class whose
main()
method randomly se-
lects one of these constants and then switches on that constant. Each of
the switch statement's cases should output a message such as
heading
north
.
Summary
Java supports advanced language features related to nested types, packages, static im-
ports, exceptions, assertions, annotations, generics, and enums.
