Question

I have a this java application i am working on to get more experience with design patterns and OODesign. The application allows the user to select “equations” from a list. And then the user will be prompted with parameters for the selected equation and will be given a button to press to solve the equations.

I am implementing the equations as a strategy pattern. I am trying to figure out how to get the names of the equations into the list box. I was wondering if there was a way for the Equation classes that implement the EquationInterface to have a variable called equationName. That would allow the programmer to assign the specific equation a name when they are coding up the class for that specific equation. Code is listed below.

Example: When the programmer is designing a new equation to add to the program, they are required to include a name for the strategy created.

If you have any questions, please let me know. I am having a hard time explaining what i am trying to accomplish. And if you have any suggestions on a better design patter to use or way of accomplishing this goal, please let me know.

public class Equation {
    public enum equationList {
        DISTANCETRAVELLEDFALLINGOVERTIME,
        TIMEFOROBJECTFALLDISTANCE
    }

    private EquationInterface solveInterface;

    public Equation(EquationInterface solveInterface) {
        this.solveInterface = solveInterface;
    }

    public void solve() {
        solveInterface.performSolve();
    }

    public JPanel getParameterPanel() {
        return solveInterface.createParameterPanel();
    }
}

---

public interface EquationInterface {

    public JPanel createParameterPanel();

    public void performSolve();
}

---

public class DistanceTravelledFallingOverTime implements EquationInterface {

    @Override
    public void performSolve() {
        // TODO Auto-generated method stub
        System.out.println("DistanceTravelledFallingOverTime");
    }

    @Override
    public JPanel createParameterPanel() {
        // TODO Auto-generated method stub
        return null;
    }

}

Answer 1

public interface EquationInterface {

    public JPanel createParameterPanel();

    public void performSolve();

    public void setEquationName(String equationName);
    public String getEquationName();
}

I would use getter type method instead of a variable.

One sample implementation

public class  SampleEquation implements EquationInterface {

    public JPanel createParameterPanel(){return null;}

    public void performSolve(){
    //solving an equation
    }

    private String equationName = "MyDefaultEquationName";// or = null

    public void setEquationName(String equationName){
      this.equationName = equationName;
    }

    public String getEquationName(){
      return this.equationName;
    }
}