public String returnStuff(SomeObject argument1, SomeObject argument2){
      if (!argument1.isValid()) {
            throw new Exception();
      }

      if (!argument2.isValid()) {
            throw new Exception();
      }

      SomeObject otherVal1 = doSomeStuff(argument1, argument2);

      if (!otherVal1.isValid()) {
            throw new Exception();
      }

      SomeObject otherVal2 = doAnotherStuff(otherVal1);

      if (!otherVal2.isValid()) {
            throw new Exception();
      }

      return "Stuff";
}