Finish the class Evaluation that implements Visitor pattern . The class takes th

Question

Finish the class Evaluation that implements Visitor pattern. The class takes the value of arguments as a Map, and evaluates an expression containing variables -- substituting the value of the variable as needed.

Given the map [ ‘x’:12, ‘y’:5] and the expression

2 * x + x / y

The new visitor would evaluate the expression and return the value 26.4

public class Evaluation extends Eval implements IVisitor {

    private Map map;

    public EvalWithVars(Map map) {
        this.map = map;
    }

    @Override
    public Object visit(Variable node) {
       // complete this method
     
       return 0.0;
    }

}

Explanation / Answer

In order to complete, the Variable java class definition is needed. Since the question does not give the code for class Variable, I presume there is a method to return the variable's name such as getName() inside Variable class. I have used getName() to access the variable's name. If there is no such method, please use its equivalent.

Please post the code for the Variable class as a comment if you want to me to help change this code.

public class Evaluation extends Eval implements IVisitor {

    private Map map;

    public EvalWithVars(Map map) {
        this.map = map;
    }

    @Override
    public Object visit(Variable node) {
       // complete this method
Object val = map.get(node.getName());

       return val;
    }

}

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