Examples of asVarargsCollector()

• java.lang.invoke.MethodHandle.asVarargsCollector()
  Static of Arrays.asList(...) produces a variable arity method handle: MethodHandle asList = publicLookup() .findStatic(Arrays.class, "asList", methodType(List.class, Object[].class)); assertEquals(methodType(List.class, Object[].class), asList.type()); assert(asList.isVarargsCollector()); assertEquals("[]", asList.invoke().toString()); assertEquals("[1]", asList.invoke(1).toString()); assertEquals("[two, too]", asList.invoke("two", "too").toString()); String[] argv = { "three", "thee", "tee" }; assertEquals("[three, thee, tee]", asList.invoke(argv).toString()); assertEquals("[three, thee, tee]", asList.invoke((Object[])argv).toString()); List ls = (List) asList.invoke((Object)argv); assertEquals(1, ls.size()); assertEquals("[three, thee, tee]", Arrays.toString((Object[])ls.get(0))); }

  Discussion: These rules are designed as a dynamically-typed variation of the Java rules for variable arity methods. In both cases, callers to a variable arity method or method handle can either pass zero or more positional arguments, or else pass pre-collected arrays of any length. Users should be aware of the special role of the final argument, and of the effect of a type match on that final argument, which determines whether or not a single trailing argument is interpreted as a whole array or a single element of an array to be collected. Note that the dynamic type of the trailing argument has no effect on this decision, only a comparison between the symbolic type descriptor of the call site and the type descriptor of the method handle.) @param arrayType often {@code Object[]}, the type of the array argument which will collect the arguments @return a new method handle which can collect any number of trailing argumentsinto an array, before calling the original method handle @throws NullPointerException if {@code arrayType} is a null reference @throws IllegalArgumentException if {@code arrayType} is not an array typeor {@code arrayType} is not assignable to this method handle's trailing parameter type @see #asCollector @see #isVarargsCollector @see #asFixedArity

Examples of java.lang.invoke.MethodHandle.asVarargsCollector()