Question

You will follow a contract-first approach using interfaces. Here are the main specifications of the contract to build the graph application. There are four interfaces.

ILocation: defines a generic interface for any location object

• It is an empty interface
• It is Comparable

ILocation

ILocation2D: defines an interface for 2D locations

• gets and sets its x and y coordinates
• it extends the generic interface ILocation

ILocation2D

ILocation3D:

• gets and sets its z coordinate.
• It extends the interface ILocation2D

ILocation3D

ICity: defines an interface for City objects.

• gets and sets
  • the name (String),
  • location (ILocation), and
• It is Comparable.

ICity

IRoute: define a generic interface for a route.

• it is Comparable and can be compared to another IRoute object.
• gets the path as a List of ICity object
• returns the length of path as a double
• returns the location of the start location of the path as ILocation object
• returns the location of the destination location of the path as ILocation object

IRoute

Answer 1

Here are all interfaces created as per specification:

1. ILocation:

package comaprableinterfaces;


public interface ILocation extends Comparable {
        //Empty interfave
}

2. ILocation2D:

package comaprableinterfaces;

//defines an interface for 2D locations
//it extends the generic interface ILocation
public interface ILocation2D extends ILocation {
        int x=0;
        int y=0;
        
        //gets and sets its x and y coordinates
        void setX(int x);
        void setY(int y);
        
        int getX();
        int getY();
}

3.ILocation3D:

package comaprableinterfaces;

//It extends the interface ILocation2D
public interface ILocation3D extends ILocation2D {
        
        int z=0;
        
        //gets and sets its z coordinate.
        void setZ(int z);
        int getZ();
}

4.ICity:

package comaprableinterfaces;

//defines an interface for City objects. and is comparable
public interface ICity extends Comparable<ICity> {

        String name=null;
        ILocation location=null;
        
        /*
         * gets and sets the name (String), location (ILocation)
         */
        void setName(String name);
        void SetLocation(ILocation location);
        
        String getName();
        ILocation getLocation();
}

5. IRoute:

package comaprableinterfaces;

import java.util.List;

//define a generic interface for a route
//it is Comparable and can be compared to another IRoute object.
public interface IRoute extends Comparable<IRoute> {

        //gets the path as a List of ICity object
        List<ICity> path=null;
        
        //returns the length of path as a double
        double lengthofPath();
        
        //returns the location of the start location of the path as ILocation object
        ILocation startLocationOfPath();
        
        //returns the location of the destination location of the path as ILocation object
        ILocation destinationLocationOfPath();
        
        
}

All Interface screenshots: