Question

In this method I get string as input and according to the string name I need to return value sometimes its string sometime int ,double,int64 ,bool etc
Since its dynamic type i don’t know how to define it in the method return type
and how to add to it the value and how to call to this method that the return type is dynamic ,any idea?

public static ? SwitchInput(String TypeName) {

       if (TypeName == "java.lang.String" ) {
            Return = "A";
        }
        else if (TypeName == "int" ) {
            Return =  1;
        }
        else if (TypeName == "double") {
            Return = 1.00
        }

etc for bool and all the other types

    }

Answer 1

To know what the return type is, you have to find a container where all these types fit in. Obviously, this is Object. You’d have to convert the primitive types to the corresponding object (like int to Integer).

A better approach would be to create a new container class, which holds a generic type <T>. Like

public class SwitchDemo {

public static SwitchInputType<?> switchInput(String typeName) {
    if (typeName.equals("java.lang.String")) {
        return new SwitchInputType<String>(new String("A"));
    } else if (typeName.equals("int")) {
        return new SwitchInputType<Integer>(new Integer(312));
    }
    return null;
}

public static class SwitchInputType<T> {
    private T type;

    public SwitchInputType(T type) {
        super();
        this.type = type;
    }

    public T getType() {
        return type;
    }

    public void setType(T type) {
        this.type = type;
    }
}

public static void main(String[] args) {
    SwitchInputType<?> sit1 = SwitchDemo.switchInput("java.lang.String");
    System.out.println(sit1.getType());
    SwitchInputType<?> sit2 = SwitchDemo.switchInput("int");
    System.out.println(sit2.getType());
}

}