private MethodHandle getMethodHandle(Method method) {
   MethodHandle methodHandle;
   try {
     methodHandle = lookup().unreflect(method);
   } catch (IllegalAccessException e) {
     throw new PrestoException(FUNCTION_IMPLEMENTATION_ERROR, e);
   }
   if (!isStatic(method.getModifiers())) {
     // Re-arrange the parameters, so that the "this" parameter is after the meta parameters
     int[] permutedIndices = new int[methodHandle.type().parameterCount()];
     permutedIndices[0] = dependencies.size();
     MethodType newType =
         methodHandle
             .type()
             .changeParameterType(dependencies.size(), methodHandle.type().parameterType(0));
     for (int i = 0; i < dependencies.size(); i++) {
       permutedIndices[i + 1] = i;
       newType = newType.changeParameterType(i, methodHandle.type().parameterType(i + 1));
     }
     for (int i = dependencies.size() + 1; i < permutedIndices.length; i++) {
       permutedIndices[i] = i;
     }
     methodHandle = permuteArguments(methodHandle, newType, permutedIndices);
   }
   return methodHandle;
 }
Esempio n. 2
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 public MethodType down(MethodType type) {
   for (int i = 0; i < type.parameterCount(); i++) {
     type = type.changeParameterType(i, type.parameterArray()[i]);
   }
   return type;
 }