Java Reference
In-Depth Information
PITFALL:
(continued)
Even though these two variables name objects that are intuitively equal, they are
stored in two different locations in the computer's memory. This is why you usually
use an
equals
method to compare objects of a class type. The variables
variable1
and
variable2
would be considered “equal” if compared using the
equals
method as
defined for the class
ToyClass2
(
Display 5.17
)
.
■
Display 5.17
A Toy Class to Use in Display 5.16
1
public
class
ToyClass2
2{
3
private
String name;
4
private
int number;
5
public void
set(String newName, int newNumber)
6
{
7
name = newName;
8
number = newNumber;
9
}
10
public
String toString()
11
{
12
return
(name + " " + number);
13
}
14
public
void
makeEqual(ToyClass2 anObject)
15
{
16
anObject.name =
this
.name;
Read the text for a discussion of
the problem with this method.
17
anObject.number =
this
.number;
18
}
19
public
void
tryToMakeEqual(
int
aNumber)
20
{
21
aNumber =
this
.number;
22
}
23
public boolean
equals(ToyClass2 otherObject)
24
{
25
return
( (name.equals(otherObject.name))
26
&& (number == otherObject.number) );
27
}
<Other methods can be the same as in Display 5.11, although no
other methods are needed or used in the current discussion.>
28
}
