Source code: ConstructorRecursion

Código fuente del programa ConstructorRecursion

Ver la entrada correspondiente en el siguiente enlace:

Java: creando objetos - Parte1

package pruebas;

import java.io.PrintStream;

public class ConstructorRecursion {
    
    public static String echoAndPrint(String aMessage) {
        System.out.format("echoAndPrint: %s%n", aMessage);

        return aMessage;
    }

    public static void main(String[] args) {
        final PrintStream out= System.out;

        Derived aux= new Derived();
        out.format("A derived object: %s%n", aux);
    }


public static class Root {

    final protected String constant= "Constant attribute.";

    public Root() {
        //Compiler calls super() automatically.
        echoAndPrint("Root constructor");
    }
}

    
public static class Base extends Root {

    //Yes, I'm using the own attribute value to initialize it.
    private String variable= echoAndPrint("Initial value: " + this.variable);
    
    public Base(String aValue) {
        //Compiler calls super() automatically.
        this.variable= echoAndPrint(aValue);
    }
    
    @Override
    public String toString() {
        String str= String.format("%s variable<%s> constant=<%s>"
            , super.toString()
            , this.variable
            , this.constant
        );

        return str;
    }
}


public static class Derived extends Base {

    private String extra;

    public Derived(String aValue) {
        super( echoAndPrint("aValue= " + aValue) );
    }
    
    public Derived() {
        this( echoAndPrint("No arguments") );
        //this( super.constant );//Error: cannot reference this before supertype constructor has been called
        //this( this.extra );//Error: cannot reference this before supertype constructor has been called
    }
}

}//End ConstructorRecursion