Java Reference
In-Depth Information
P
ROJECTS
1.
Define a pair of companion classes modeled after the class
Student
, as given in Segment C.2 of Appendix C.
Project 5 in Chapter 7 asked you to write a class
KnapsackItem
of items that would be placed in a list. Design
and implement a pair of companion classes for such knapsack items.
2.
Project 6 in Chapter 7 asked you to write a class
Activity
of activities that would be placed in a list. Design and
implement a pair of companion classes for such activities.
3.
4.
Chapter 13 describes an implementation of the ADT list that uses an instance of the class
Vector
to represent the
entries in the list. Write a
clone
method for this implementation and demonstrate that it works. Note that
Vector
implements the interface
Cloneable
.
5.
Revise the linked implementation of the ADT sorted list, as given in Chapter 16, according to the suggestions
about cloning given in Segment 30.31. That is, the method
add
should place a clone of the desired entry, instead of
the entry itself, into the sorted list. Additionally, the method
getEntry
should return a clone of the desired entry,
instead of returning the entry itself.
6.
Suppose that you wanted to implement a deep copy for the class
FamilyMember
defined in Exercise 15 in this
chapter.
a.
What difficulty will arise?
b.
Implement a
clone
method for
FamilyMember
that makes a deep copy.
7.
Define three classes—
A
,
B
, and
C
—such that
C
is a subclass of
B
, and
B
is a subclass of
A
. Each class should define
a
clone
method and have at least one data field that is a mutable, cloneable object.
A
NSWERS
TO
S
ELF
-T
EST
Q
UESTIONS
1.
public
ImmutableName(Name aName)
{
first = aName.getFirst();
last = aName.getLast();
}
// end constructor
2.
// Create an object of the class Name
Name derek =
new
Name("Derek", "Greene");
// Convert the object to an immutable object; don't change its data fields
ImmutableName derekI = derek.getImmutable();
// Add the immutable object to the sorted list nameList
SortedListInterface<ImmutableName> nameList =
new
SortedList<ImmutableName>();
nameList.add(derekI);
3.
// Create an object of the class ImmutableName
ImmutableName lila =
new
ImmutableName("Lila", "Bleu");
// Convert the object to a mutable object; don't change its data fields
Name changer = lila.getMutable();
// Change the last name of the new object
changer.setLast("Greene");
// Convert the revised mutable object to an immutable object
ImmutableName unchanger = changer.getImmutable();
4.
a.
No. The clone
y
has a name object that is distinct from
x
's name object, because a deep copy was made.
(See Figure 30-7.)
b.
Yes. Both objects share one name object. (See Figure 30-8.)
