1 /*

        2  * Copyright (c) 2010, 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 /*

       25  * @test

       26  * @summary basic test for lambda conversion

       27  * @author  Brian Goetz

       28  * @author  Maurizio Cimadamore

       29  * @run main LambdaConv01

       30  */

       31 

       32 public class LambdaConv01 {

       33 

       34     static int assertionCount = 0;

       35 

       36     static void assertTrue(boolean cond) {

       37         assertionCount++;

       38         if (!cond)

       39             throw new AssertionError();

       40     }

       41 

       42     interface IntToInt {

       43       public int foo(int x);

       44     }

       45 

       46     interface IntToVoid {

       47       public void foo(int x);

       48     }

       49 

       50     interface VoidToInt {

       51       public int foo();

       52     }

       53 

       54     interface TU<T, U> {

       55       public T foo(U u);

       56     }

       57 

       58     public static <T, U> T exec(TU<T, U> lambda, U x) {

       59         return lambda.foo(x);

       60     }

       61 

       62     static {

       63         //Assignment conversion:

       64         VoidToInt f1 = #{3};

       65         assertTrue(3 == f1.foo());

       66         //Covariant returns:

       67         TU<Number, Integer> f2 = #{ Integer x -> x };

       68         assertTrue(3 == f2.foo(3));

       69         //Method resolution with boxing:

       70         int x = LambdaConv01.<Integer,Integer>exec(#{ Integer x -> x }, 3);

       71         assertTrue(3 == x);

       72         //Runtime exception transparency:

       73         try {

       74             LambdaConv01.<Integer,Object>exec(#{ Object x -> x.hashCode() }, null);

       75         }

       76         catch (RuntimeException e) {

       77             assertTrue(true);

       78         }

       79     }

       80 

       81     {

       82         //Assignment conversion:

       83         VoidToInt f1 = #{3};

       84         assertTrue(3 == f1.foo());

       85         //Covariant returns:

       86         TU<Number, Integer> f2 = #{ Integer x -> x };

       87         assertTrue(3 == f2.foo(3));

       88         //Method resolution with boxing:

       89         int x = LambdaConv01.<Integer,Integer>exec(#{ Integer x -> x }, 3);

       90         assertTrue(3 == x);

       91         //Runtime exception transparency:

       92         try {

       93             LambdaConv01.<Integer,Object>exec(#{ Object x -> x.hashCode() }, null);

       94         }

       95         catch (RuntimeException e) {

       96             assertTrue(true);

       97         }

       98     }

       99 

      100     public static void test1() {

      101         //Assignment conversion:

      102         VoidToInt f1 = #{3};

      103         assertTrue(3 == f1.foo());

      104         //Covariant returns:

      105         TU<Number, Integer> f2 = #{ Integer x -> x };

      106         assertTrue(3 == f2.foo(3));

      107         //Method resolution with boxing:

      108         int x = LambdaConv01.<Integer,Integer>exec(#{ Integer x -> x }, 3);

      109         assertTrue(3 == x);

      110         //Runtime exception transparency:

      111         try {

      112             LambdaConv01.<Integer,Object>exec(#{ Object x -> x.hashCode() }, null);

      113         }

      114         catch (RuntimeException e) {

      115             assertTrue(true);

      116         }

      117     }

      118 

      119     public void test2() {

      120         //Assignment conversion:

      121         VoidToInt f1 = #{3};

      122         assertTrue(3 == f1.foo());

      123         //Covariant returns:

      124         TU<Number, Integer> f2 = #{ Integer x -> x };

      125         assertTrue(3 == f2.foo(3));

      126         //Method resolution with boxing:

      127         int x = LambdaConv01.<Integer,Integer>exec(#{ Integer x -> x }, 3);

      128         assertTrue(3 == x);

      129         //Runtime exception transparency:

      130         try {

      131             LambdaConv01.<Integer,Object>exec(#{ Object x -> x.hashCode() }, null);

      132         }

      133         catch (RuntimeException e) {

      134             assertTrue(true);

      135         }

      136     }

      137 

      138     public static void main(String[] args) {

      139         test1();

      140         new LambdaConv01().test2();

      141         assertTrue(assertionCount == 16);

      142     }

      143 }