Java Reference
In-Depth Information
course, you could have kept the name of the formal parameters as before and still used the
reference this as shown in the code.
Similarly, explicitly using the reference this , you can write the definition of the method
incrementSeconds as follows:
public void incrementSeconds()
{
this .sec++;
if ( this .sec > 59)
{
this .sec = 0;
this .incrementMinutes(); //increment minutes
}
}
Cascaded Method Calls (Optional)
In addition to explicitly referring to the instance variables and methods of an object, the
reference this has another use—to implement cascaded method calls. We explain this
with the help of an example.
In Example 8-8, we designed the class Person to implement a person's name in a
program. Here, we extend the definition of the class Person to individually set a
person's first name and last name, and then return a reference to the object, using this .
The following code is the extended definition of the class Person . (The methods
setFirstName and setLastName are added to this definition of the class Person .)
public class Person
{
private String firstName; //store the first name
private String lastName;
//store the last name
//Default constructor;
//Initialize firstName and lastName to empty string.
//Postcondition: firstName = ""; lastName = "";
public Person()
{
firstName = "";
lastName = "";
}
//Constructor with parameters
//Set firstName and lastName according to the parameters.
//Postcondition: firstName = first; lastName = last;
public Person(String first, String last)
{
setName(first, last);
}
 
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