Java Reference
In-Depth Information
Display 5.20
The Class
Date
(Partial Dei nition)
(part 2 of 2)
39 System.out.println("Fatal Error");
40 System.exit(0);
41 }
42
else
43
this
.year = year;
44 }
45
public
String toString()
46 ...
47
public boolean
equals(Date otherDate)
48 ....
49 /**
50
Returns true if the calling object date is before otherDate (in time).
The complete definition of
equals
is
given later in this chapter in the
answer to Self-Test
Exercise 37, and is a
better version than the
one given in Chapter 4.
51 */
52
public boolean
precedes(Date otherDate)
53 ...
54
private boolean
dateOK(String monthString,
int
dayInt,
int
yearInt)
55 ...
These methods have the obvious meanings. If you need to see a full definition,
see Display 4.11 in Chapter 4 and Self-Test Exercise 37 later in this chapter.
56 }
Self-Test Exercises
36. What is the difference between the following two pieces of code? The fi rst piece
appears in Display 5.21 .
Person adams =
new
Person("John Adams",
new
Date("February", 15, 1947),
null
);
//Second piece is below:
Date theDate =
new
Date("February", 15, 1947);
Person adams =
new
Person("John Adams", theDate,
null
);
37. When we defi ned the class
Date
in Chapter 4 (Display 4.11), we had not yet
discussed
null
. So, the defi nition of
equals
given there did not account for the
possibility that the argument could be
null
. Rewrite the defi nition of
equals
for
the class
Date
to account for the possibility that the argument might be
null
.
