1 /*
   2  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 package java.lang.invoke;
  25 
  26 import sun.invoke.util.Wrapper;
  27 
  28 /* @test
  29  * @summary unit tests for MethodHandles.explicitCastArguments()
  30  *
  31  * @run main/bootclasspath java.lang.invoke.ExplicitCastArgumentsTest
  32  */
  33 public class ExplicitCastArgumentsTest {
  34     private static final boolean VERBOSE = Boolean.getBoolean("verbose");
  35     private static final Class<?> THIS_CLASS = ExplicitCastArgumentsTest.class;
  36 
  37     public static void main(String[] args) throws Throwable {
  38         testVarargsCollector();
  39         testRef2Prim();
  40         System.out.println("TEST PASSED");
  41     }
  42 
  43     public static String[] f(String... args) { return args; }
  44 
  45     public static void testVarargsCollector() throws Throwable {
  46         MethodType mt = MethodType.methodType(String[].class, String[].class);
  47         MethodHandle mh = MethodHandles.publicLookup().findStatic(THIS_CLASS, "f", mt);
  48         mh = MethodHandles.explicitCastArguments(mh, MethodType.methodType(Object.class, Object.class));
  49         mh.invokeWithArguments((Object)(new String[] {"str1", "str2"}));
  50     }
  51 
  52     public static void testRef2Prim() throws Throwable {
  53         for (Wrapper from : Wrapper.values()) {
  54             for (Wrapper to : Wrapper.values()) {
  55                 if (from == Wrapper.VOID || to == Wrapper.VOID) continue;
  56                 testRef2Prim(from, to);
  57             }
  58         }
  59     }
  60 
  61     public static void testRef2Prim(Wrapper from, Wrapper to) throws Throwable {
  62         // MHs.eCA javadoc:
  63         //    If T0 is a reference and T1 a primitive, and if the reference is null at runtime, a zero value is introduced.
  64         test(from.wrapperType(), to.primitiveType(), null, false);
  65     }
  66 
  67     public static void test(Class<?> from, Class<?> to, Object param, boolean failureExpected) throws Throwable {
  68         if (VERBOSE) System.out.printf("%-10s => %-10s: %5s: ", from.getSimpleName(), to.getSimpleName(), param);
  69 
  70         MethodHandle original = MethodHandles.identity(from);
  71         MethodType newType = original.type().changeReturnType(to);
  72 
  73         try {
  74             MethodHandle target = MethodHandles.explicitCastArguments(original, newType);
  75             Object result = target.invokeWithArguments(param);
  76 
  77             if (VERBOSE) {
  78                 String resultStr;
  79                 if (result != null) {
  80                     resultStr = String.format("%10s (%10s)", "'"+result+"'", result.getClass().getSimpleName());
  81                 } else {
  82                     resultStr = String.format("%10s", result);
  83                 }
  84                 System.out.println(resultStr);
  85             }
  86 
  87             if (failureExpected) {
  88                 String msg = String.format("No exception thrown: %s => %s; parameter: %s", from, to, param);
  89                 throw new AssertionError(msg);
  90             }
  91         } catch (AssertionError e) {
  92             throw e; // report test failure
  93         } catch (Throwable e) {
  94             if (VERBOSE) System.out.printf("%s: %s\n", e.getClass(), e.getMessage());
  95             if (!failureExpected) {
  96                 String msg = String.format("Unexpected exception was thrown: %s => %s; parameter: %s", from, to, param);
  97                 throw new AssertionError(msg, e);
  98             }
  99         }
 100     }
 101 }