import java.util.List; public class SuperBuilderBasicToBuilder { public static class Parent { private int field1; int obtainViaField; int obtainViaMethod; String obtainViaStaticMethod; List<String> items; private int method() { return 2; } private static String staticMethod(Parent instance) { return "staticMethod"; } @java.lang.SuppressWarnings("all") public static abstract class ParentBuilder<C extends Parent, B extends ParentBuilder<C, B>> { @java.lang.SuppressWarnings("all") private int field1; @java.lang.SuppressWarnings("all") private int obtainViaField; @java.lang.SuppressWarnings("all") private int obtainViaMethod; @java.lang.SuppressWarnings("all") private String obtainViaStaticMethod; @java.lang.SuppressWarnings("all") private java.util.ArrayList<String> items; @java.lang.SuppressWarnings("all") protected B $fillValuesFrom(final C instance) { ParentBuilder.$fillValuesFromInstanceIntoBuilder(instance, this); return self(); } @java.lang.SuppressWarnings("all") private static void $fillValuesFromInstanceIntoBuilder(final Parent instance, final ParentBuilder<?, ?> b) { b.field1(instance.field1); b.obtainViaField(instance.field1); b.obtainViaMethod(instance.method()); b.obtainViaStaticMethod(Parent.staticMethod(instance)); b.items(instance.items == null ? java.util.Collections.emptyList() : instance.items); } @java.lang.SuppressWarnings("all") protected abstract B self(); @java.lang.SuppressWarnings("all") public abstract C build(); @java.lang.SuppressWarnings("all") public B field1(final int field1) { this.field1 = field1; return self(); } @java.lang.SuppressWarnings("all") public B obtainViaField(final int obtainViaField) { this.obtainViaField = obtainViaField; return self(); } @java.lang.SuppressWarnings("all") public B obtainViaMethod(final int obtainViaMethod) { this.obtainViaMethod = obtainViaMethod; return self(); } @java.lang.SuppressWarnings("all") public B obtainViaStaticMethod(final String obtainViaStaticMethod) { this.obtainViaStaticMethod = obtainViaStaticMethod; return self(); } @java.lang.SuppressWarnings("all") public B item(final String item) { if (this.items == null) this.items = new java.util.ArrayList<String>(); this.items.add(item); return self(); } @java.lang.SuppressWarnings("all") public B items(final java.util.Collection<? extends String> items) { if (this.items == null) this.items = new java.util.ArrayList<String>(); this.items.addAll(items); return self(); } @java.lang.SuppressWarnings("all") public B clearItems() { if (this.items != null) this.items.clear(); return self(); } @java.lang.Override @java.lang.SuppressWarnings("all") public java.lang.String toString() { return "SuperBuilderBasicToBuilder.Parent.ParentBuilder(field1=" + this.field1 + ", obtainViaField=" + this.obtainViaField + ", obtainViaMethod=" + this.obtainViaMethod + ", obtainViaStaticMethod=" + this.obtainViaStaticMethod + ", items=" + this.items + ")"; } } @java.lang.SuppressWarnings("all") private static final class ParentBuilderImpl extends ParentBuilder<Parent, ParentBuilderImpl> { @java.lang.SuppressWarnings("all") private ParentBuilderImpl() { } @java.lang.Override @java.lang.SuppressWarnings("all") protected ParentBuilderImpl self() { return this; } @java.lang.Override @java.lang.SuppressWarnings("all") public Parent build() { return new Parent(this); } } @java.lang.SuppressWarnings("all") protected Parent(final ParentBuilder<?, ?> b) { this.field1 = b.field1; this.obtainViaField = b.obtainViaField; this.obtainViaMethod = b.obtainViaMethod; this.obtainViaStaticMethod = b.obtainViaStaticMethod; java.util.List<String> items; switch (b.items == null ? 0 : b.items.size()) { case 0: items = java.util.Collections.emptyList(); break; case 1: items = java.util.Collections.singletonList(b.items.get(0)); break; default: items = java.util.Collections.unmodifiableList(new java.util.ArrayList<String>(b.items)); } this.items = items; } @java.lang.SuppressWarnings("all") public static ParentBuilder<?, ?> builder() { return new ParentBuilderImpl(); } @java.lang.SuppressWarnings("all") public ParentBuilder<?, ?> toBuilder() { return new ParentBuilderImpl().$fillValuesFrom(this); } } public static class Child extends Parent { private double field3; @java.lang.SuppressWarnings("all") public static abstract class ChildBuilder<C extends Child, B extends ChildBuilder<C, B>> extends Parent.ParentBuilder<C, B> { @java.lang.SuppressWarnings("all") private double field3; @java.lang.Override @java.lang.SuppressWarnings("all") protected B $fillValuesFrom(final C instance) { super.$fillValuesFrom(instance); ChildBuilder.$fillValuesFromInstanceIntoBuilder(instance, this); return self(); } @java.lang.SuppressWarnings("all") private static void $fillValuesFromInstanceIntoBuilder(final Child instance, final ChildBuilder<?, ?> b) { b.field3(instance.field3); } @java.lang.Override @java.lang.SuppressWarnings("all") protected abstract B self(); @java.lang.Override @java.lang.SuppressWarnings("all") public abstract C build(); @java.lang.SuppressWarnings("all") public B field3(final double field3) { this.field3 = field3; return self(); } @java.lang.Override @java.lang.SuppressWarnings("all") public java.lang.String toString() { return "SuperBuilderBasicToBuilder.Child.ChildBuilder(super=" + super.toString() + ", field3=" + this.field3 + ")"; } } @java.lang.SuppressWarnings("all") private static final class ChildBuilderImpl extends ChildBuilder<Child, ChildBuilderImpl> { @java.lang.SuppressWarnings("all") private ChildBuilderImpl() { } @java.lang.Override @java.lang.SuppressWarnings("all") protected ChildBuilderImpl self() { return this; } @java.lang.Override @java.lang.SuppressWarnings("all") public Child build() { return new Child(this); } } @java.lang.SuppressWarnings("all") protected Child(final ChildBuilder<?, ?> b) { super(b); this.field3 = b.field3; } @java.lang.SuppressWarnings("all") public static ChildBuilder<?, ?> builder() { return new ChildBuilderImpl(); } @java.lang.SuppressWarnings("all") public ChildBuilder<?, ?> toBuilder() { return new ChildBuilderImpl().$fillValuesFrom(this); } } public static void test() { Child x = Child.builder().field3(0.0).field1(5).item("").build().toBuilder().build(); } }