Compile-time Builder Pattern in Java

Builder pattern is a pattern that is usually used for a language that does not support named parameters. However, the typical builder pattern has a limitation, such at it can't at compile-time check the required parameters. Below are some suggestions how to use a builder pattern that has compile-time check.

• Option 1
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public class Foo {     private String a;     private String b;     private String c;       private Foo() {     }       public static ABuilder newBuilder() {         return new ABuilder(new Foo());     }       private static class ABuilder {         private final Foo foo;           private ABuilder(Foo foo) {             this.foo = foo;         }           public BBuilder a(String a) {             foo.a = a;             return new BBuilder(foo);         }     }       private static class BBuilder {         private final Foo foo;           private BBuilder(Foo foo) {             this.foo = foo;         }           public CBuilder b(String b) {             foo.b = b;             return new CBuilder(foo);         }     }       private static class CBuilder {         private final Foo foo;           private CBuilder(Foo foo) {             this.foo = foo;         }           public FinalBuilder c(String c) {             foo.c = c;             return new FinalBuilder(foo);         }     }       private static class FinalBuilder {         private final Foo foo;           private FinalBuilder(Foo foo) {             this.foo = foo;         }           public Foo build() {             return foo;         }     }       public static void main(String[] args) {         Foo foo = Foo.newBuilder().a("a").b("b").c("c").build();         System.out.println(foo);     } }

• Option 2
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public class Bar {     private final String a;     private final String b;     private final String c;       public static class False {}     public static class True {}       public static class Builder<Has1, Has2, Has3> {         private String a;         private String b;         private String c;           public static Builder<False, False, False> create() {             return new Builder<>();         }           public Builder<True, Has2, Has3> a(String a) {             this.a = a;             return (Builder<True, Has2, Has3>) this;         }           public Builder<Has1, True, Has3> b(String b) {             this.b = b;             return (Builder<Has1, True, Has3>) this;         }           public Builder<Has1, Has2, True> c(String c) {             this.c = c;             return (Builder<Has1, Has2, True>) this;         }     }       public Bar(Builder<True, True, True> builder) {         a = builder.a;         b = builder.b;         c = builder.c;     }       public static void main(String[] args) {         Bar bar = new Bar(Builder.create().a("a").b("c").c("a"));         System.out.println(bar);     } }