import static java.lang.invoke.MethodHandles.*;
import static java.lang.invoke.MethodType.methodType;

import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodType;

public class MethodHandleChain {
    public static void main(String[] args) {
        Class<?> rt = Object.class;

        MethodHandle ctor = empty(methodType(rt, String.class));
        MethodHandle read1 = empty(methodType(void.class, rt, Long.class));
        MethodHandle read2 = empty(methodType(void.class, rt, Integer.class));


        MethodHandle result = identity(rt);

        result = dup(collectArguments(result, 1, read2));
        result = dup(collectArguments(result, 1, read1));

        result = collectArguments(result, 0, ctor);
        System.out.println(result);
    }

    // Duplicates parameter at pos 0
    private static MethodHandle dup(MethodHandle mh) {
        MethodType mt = mh.type();
        if (mt.parameterType(0) != mt.parameterType(1)) {
            throw new IllegalArgumentException("First 2 parameters need to have the same type, got " + mt);
        }
        MethodType newMT = mt.dropParameterTypes(0, 1);
        int[] permutation = new int[mt.parameterCount()];
        permutation[0] = 0;
        for (int i = 0; i < newMT.parameterCount(); i++) {
            permutation[i + 1] = i;
        }
        return permuteArguments(mh, newMT, permutation);
    }
}