Builder pattern for polymorphic object hierarchy: possible with Java?

Question

I have a hierarchy of interfaces, with Child implementing Parent. I would like to work with immutable objects, so I would like to design Bui

Answer 1

package so9138027take2;
import java.util.*;
import so9138027take2.C2.Names;
interface P {
    public Object getParentProperty(Names name);
    enum Names {
        i(Integer.class), d(Double.class), s(String.class);
        Names(Class clazz) {
            this.clazz = clazz;
        }
        final Class clazz;
    }
}
interface C1 extends P {
    public Object getChildProperty(Names name);
    enum Names {
        a(Integer.class), b(Double.class), c(String.class);
        Names(Class clazz) {
            this.clazz = clazz;
        }
        final Class clazz;
    }
}
interface C2 extends P {
    public Object getChildProperty(Names name);
    enum Names {
        x(Integer.class), y(Double.class), z(String.class);
        Names(Class clazz) {
            this.clazz = clazz;
        }
        final Class clazz;
    }
}
abstract class PABCImmutable implements P {
    public PABCImmutable(PABC parent) {
        parentNameToValue = Collections.unmodifiableMap(parent.parentNameToValue);
    }
    @Override public final Object getParentProperty(Names name) {
        return parentNameToValue.get(name);
    }
    public String toString() {
        return parentNameToValue.toString();
    }
    final Map parentNameToValue;
}
abstract class PABC implements P {
    @Override public final Object getParentProperty(Names name) {
        return parentNameToValue.get(name);
    }
    protected PABC setParentProperty(Names name, Object value) {
        if (name.clazz.isInstance(value)) parentNameToValue.put(name, value);
        else
            throw new RuntimeException("value is not valid for " + name);
        return this;
    }
    public String toString() {
        return parentNameToValue.toString();
    }
    EnumMap parentNameToValue = new EnumMap(P.Names.class);
}
final class C1Immutable extends PABCImmutable implements C1 {
    public C1Immutable(C1Impl c1) {
        super(c1);
        nameToValue =  Collections.unmodifiableMap(c1.nameToValue);
    }
    @Override public Object getChildProperty(C1.Names name) {
        return nameToValue.get(name);
    }
    public String toString() {
        return super.toString() + nameToValue.toString();
    }
    final Map nameToValue;
}
final class C1Impl extends PABC implements C1 {
    @Override public Object getChildProperty(C1.Names name) {
        return nameToValue.get(name);
    }
    public Object setChildProperty(C1.Names name, Object value) {
        if (name.clazz.isInstance(value)) nameToValue.put(name, value);
        else
            throw new RuntimeException("value is not valid for " + name);
        return this;
    }
    public String toString() {
        return super.toString() + nameToValue.toString();
    }
    EnumMap nameToValue = new EnumMap(C1.Names.class);
}
final class C2Immutable extends PABCImmutable implements C2 {
    public C2Immutable(C2Impl c2) {
        super(c2);
        this.nameToValue = Collections.unmodifiableMap(c2.nameToValue);
    }
    @Override public Object getChildProperty(C2.Names name) {
        return nameToValue.get(name);
    }
    public String toString() {
        return super.toString() + nameToValue.toString();
    }
    final Map nameToValue;
}
final class C2Impl extends PABC implements C2 {
    @Override public Object getChildProperty(C2.Names name) {
        return nameToValue.get(name);
    }
    public Object setChildProperty(C2.Names name, Object value) {
        if (name.clazz.isInstance(value)) {
            nameToValue.put(name, value);
        } else {
            System.out.println("name=" + name + ", value=" + value);
            throw new RuntimeException("value is not valid for " + name);
        }
        return this;
    }
    public String toString() {
        return super.toString() + nameToValue.toString();
    }
    EnumMap nameToValue = new EnumMap(C2.Names.class);
}
public class So9138027take2 {
    public static void main(String[] args) {
        Object[] parentValues = new Object[] { 1, 2., "foo" };
        C1Impl c1 = new C1Impl();
        Object[] c1Values = new Object[] { 3, 4., "bar" };
        for (P.Names name : P.Names.values())
            c1.setParentProperty(name, parentValues[name.ordinal()]);
        for (C1.Names name : C1.Names.values())
            c1.setChildProperty(name, c1Values[name.ordinal()]);
        C2Impl c2 = new C2Impl();
        Object[] c2Values = new Object[] { 5, 6., "baz" };
        for (P.Names name : P.Names.values())
            c2.setParentProperty(name, parentValues[name.ordinal()]);
        for (C2.Names name : C2.Names.values())
            c2.setChildProperty(name, c2Values[name.ordinal()]);
        C1 immutableC1 = new C1Immutable(c1);
        System.out.println("child 1: "+immutableC1);
        C2 immutableC2 = new C2Immutable(c2);
        System.out.println("child 2: "+immutableC2);
    }
}