Question

I’m just learning about interfaces and their significance in java, is it necessary to create a interface for an inner class such as the program i have created below? The purpose of this class is just to be a vague archetype of the government and how it operates in its simplest form. I have created several methods adding laws, senators, and congress members. Does this code work for what i am trying to accomplish?

public class usaGov
{

private int sizeOfSenate = 105;
private int sizeOfCongress = 308;
private int amtOfLaws = 0;
private int law = 0;

void addSenateMember(int numberOfSenators)
{        
        sizeOfSenate = sizeOfSenate + numberOfSenators;
}

void addCongressMember(int numberOfCongressMembers)
{
    sizeOfCongress = sizeOfCongress + numberOfCongressMembers;
}    

void removeSenateMember(int numberOfSenators)
{        
       sizeOfSenate = sizeOfSenate - numberOfSenators;   
}

void removeCongressMember (int numberOfCongressMembers)
{
    sizeOfCongress = sizeOfCongress - numberOfCongressMembers;
}

void passLaw()
{
    if (law == 3)
    {
        amtOfLaws++;
    }

}

private class Senate 
{
void senateYes()
{
    int yes = 1; 
    law = law + yes;
}
void senateNo()
{
    int no = -1;
    law = law + no;
}

}
private class Congress
{ 
void congressYes()
{
    int yes = 1;
    law = law + yes;
}
void congressNo()
{
    int no = -1;
    law = law + no;
}
}
private class President
{
void presidentYes()
{
    int yes = 1;
    law = law + yes;
}
void presidentNo()
{
    int no = -1;
    law = law + no;
}
}    


}

Here is my interface:

public interface americanGov
{
void addSenateMember(int numberOfSenators);

void addCongressMember(int numberOfCongressMembers);

void removeSenateMember(int numberOfSenators);

void removeCongressMember (int numberOfCongressMembers);
}

Answer 1

In your case, all the law voting share the same code. You can significantly shorten and simplyfy the code by using only one class for all voting:

public class USAGOV {

    private VotingBody senate = new VotingBody(105);
    private VotingBody congress = new VotingBody(305);
    private VotingBody president = new VotingBody(1);

    void passLaw() {
        //logic to count votes from senate, congress and president
    }

    private class VotingBody {
        int members;
        int law;

        VotingBody(int members){
            this.members = members;
        }

        int getSize() {
            return members;
        }

        void voteYes() {
            int yes = 1;
            law = law + yes;
        }

        void voteNo() {
            int no = -1;
            law = law + no;
        }

        void addMembers(int members){
            this.members += members;
        }

        void removeMembers(int members){
            this.members -= members;
        }

    }
}