Some information
Creational Patterns - Factory Pattern
Factory of what? Of classes. In simple words, if we have a super class and n sub-classes, and based on data provided, we have to return the object of one of the sub-classes, we use a factory pattern.
Let�s take an example to understand this pattern.
Example: Let�s suppose an application asks for entering the name and sex of a person. If the sex is Male (M), it displays welcome message saying Hello Mr. <Name> and if the sex is Female (F), it displays message saying Hello Ms <Name>.
The skeleton of the code can be given here.
public class Person {
// name
string public String name;
// gender : M or F
private String gender;
public String getName() {
return name;
}
public String getGender() {
return gender;
}
}// End of class
This is a simple class Person having methods for name and gender. Now, we will have two sub-classes, Male and Female which will print the welcome message on the screen.
public class Male extends Person {
public Male(String fullName) {
System.out.println("Hello Mr. "+fullName);
}
}// End of class
Also, the class Female
public class Female extends Person {
public Female(String fullNname) {
System.out.println("Hello Ms. "+fullNname);
}
}// End of class
Now, we have to create a client, or a SalutationFactory which will return the welcome message depending on the data provided.
public class SalutationFactory {
public static void main(String args[]) {
SalutationFactory factory = new SalutationFactory();
factory.getPerson(args[0], args[1]);
}
public Person getPerson(String name, String gender) {
if (gender.equals("M"))
return new Male(name);
else if(gender.equals("F"))
return new Female(name);
else
return null;
}
}// End of class
This class accepts two arguments from the system at runtime and prints the names.
Hope this help
