Java Reference
In-Depth Information
Note
Aclassthatisdeclared
public
mustbestoredinafilewiththesamename.
Forexample,a
public Image
classmustbestoredin
Image.java
.Asourcefile
can declare one
public
class only.
Youwilloftendeclareyourclass'sinstancefieldstobe
private
andprovidespecial
public
instancemethodsforsettingandgettingtheirvalues.Byconvention,methods
thatsetfieldvalueshavenamesstartingwith
set
andareknownas
setters
.Similarly,
methodsthatgetfieldvalueshavenameswith
get
(or
is
,forBooleanfields)prefixes
and are known as
getters
.
Listing 2-13
demonstrates this pattern in the context of an
Employee
class declaration.
Listing 2-13.
Separation of interface from implementation
public class Employee
{
private String name;
public Employee(String name)
{
setName(name);
}
public void setName(String empName)
{
name = empName; // Assign the empName argument to the
name field.
}
public String getName()
{
return name;
}
}
public
constructor,andits
public
setter/gettermethods.Thisclassandthesemem-
bers can be accessed from anywhere. The implementation consists of the
private
name
fieldandconstructor/methodcode,whichisonlyaccessiblewithinthe
Employ-
ee
class.