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 capture of non-mutable locals

       27  * @author  Brian Goetz

       28  * @author  Maurizio Cimadamore

       29  * @run main LambdaCapture01

       30  */

       31 

       32 public class LambdaCapture01 {

       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 Tester {

       43         void test();

       44     }

       45 

       46     interface TU<T, U> {

       47         public T foo(U u);

       48     }

       49 

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

       51         return lambda.foo(x);

       52     }

       53 

       54     public int n = 5;

       55 

       56     //Simple local capture

       57     void test1() {

       58         final int N = 1;

       59         int x = LambdaCapture01.<Integer,Integer>exec(#{ Integer x -> x + N }, 3);

       60         assertTrue(4 == x);

       61     }

       62 

       63     //Local capture with multiple scopes (anon class)

       64     void test2() {

       65         final int N = 1;

       66         new Tester() {

       67             public void test() {

       68                 final int M = 2;

       69                 int x = LambdaCapture01.<Integer,Integer>exec(#{ Integer x -> x + N + M }, 3);

       70                 assertTrue(6 == x);

       71             }

       72         }.test();

       73     }

       74 

       75     //Local capture with multiple scopes (local class)

       76     void test3() {

       77         final int N = 1;

       78         class MyTester implements Tester {

       79             public void test() {

       80                 final int M = 2;

       81                 int x = LambdaCapture01.<Integer,Integer>exec(#{ Integer x -> x + N + M }, 3);

       82                 assertTrue(6 == x);

       83             }

       84         }

       85         new MyTester().test();

       86     }

       87 

       88     //access to field from enclosing scope

       89     void test4() {

       90         final int N = 4;

       91         int x1 = LambdaCapture01.<Integer,Integer>exec(#{ Integer x -> x + n + N }, 3);

       92         assertTrue(12 == x1);

       93         int x2 = LambdaCapture01.<Integer,Integer>exec(#{ Integer x -> x + LambdaCapture01.this.n + N }, 3);

       94         assertTrue(12 == x2);

       95     }

       96 

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

       98         LambdaCapture01 t = new LambdaCapture01();

       99         t.test1();

      100         t.test2();

      101         t.test3();

      102         t.test4();

      103         assertTrue(assertionCount == 5);

      104     }

      105 }