Json.java

public abstract class Json {

    private Json() {
    }

    public abstract <T> T match(Function<Jseq, T> a,
                                Function<Jobj, T> b,
                                Function<Jnumber, T> c,
                                Function<Jstring, T> d,
                                Function<Jboolean, T> e,
                                Function<JNull, T> f
    );

    public static final class Jseq extends Json {
        private final List<Json> elems;

        public Jseq(final List<Json> elems) {
            this.elems = elems;
        }

        public List<Json> getElems() {
            return elems;
        }

        @Override
        public <T> T match(final Function<Jseq, T> a,
                           final Function<Jobj, T> b,
                           final Function<Jnumber, T> c,
                           final Function<Jstring, T> d,
                           final Function<Jboolean, T> e,
                           final Function<JNull, T> f) {
            return a.apply(this);
        }
    }

    public static final class Jobj extends Json {
        private final Map<String, Json> members;

        public Jobj(final Map<String, Json> members) {
            this.members = members;
        }

        public Map<String, Json> getMembers() {
            return members;
        }

        @Override
        public <T> T match(final Function<Jseq, T> a,
                           final Function<Jobj, T> b,
                           final Function<Jnumber, T> c,
                           final Function<Jstring, T> d,
                           final Function<Jboolean, T> e,
                           final Function<JNull, T> f) {
            return b.apply(this);
        }
    }

    public static final class Jnumber extends Json {
        private final Double num;

        public Jnumber(final double num) {
            this.num = num;
        }

        public Double getNum() {
            return num;
        }

        @Override
        public <T> T match(final Function<Jseq, T> a,
                           final Function<Jobj, T> b,
                           final Function<Jnumber, T> c,
                           final Function<Jstring, T> d,
                           final Function<Jboolean, T> e,
                           final Function<JNull, T> f) {
            return c.apply(this);
        }
    }

    public static final class Jstring extends Json {
        private final String str;

        public Jstring(final String str) {
            this.str = str;
        }

        public String getStr() {
            return str;
        }

        @Override
        public <T> T match(final Function<Jseq, T> a,
                           final Function<Jobj, T> b,
                           final Function<Jnumber, T> c,
                           final Function<Jstring, T> d,
                           final Function<Jboolean, T> e,
                           final Function<JNull, T> f) {
            return d.apply(this);
        }
    }

    public static final class Jboolean extends Json {
        private final Boolean b;

        public Jboolean(final Boolean b) {
            this.b = b;
        }

        public Boolean getB() {
            return b;
        }

        @Override
        public <T> T match(final Function<Jseq, T> a,
                           final Function<Jobj, T> b,
                           final Function<Jnumber, T> c,
                           final Function<Jstring, T> d,
                           final Function<Jboolean, T> e,
                           final Function<JNull, T> f) {
            return e.apply(this);
        }
    }

    public static final class JNull extends Json {
        public JNull() {
        }

        @Override
        public <T> T match(final Function<Jseq, T> a,
                           final Function<Jobj, T> b,
                           final Function<Jnumber, T> c,
                           final Function<Jstring, T> d,
                           final Function<Jboolean, T> e,
                           final Function<JNull, T> f) {
            return f.apply(this);
        }
    }
}