test/langtools/tools/javac/lambda/methodReference/MethodRefSingleRefEvalBridge.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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/**
 * @test
 * @bug 8048121
 * @summary javac complex method references: revamp and simplify
 *
 * Make sure that the method reference receiver is evaluated exactly once
 * even in this bridging case.
 */

 public class MethodRefSingleRefEvalBridge {

    interface SAM {
       int m();
    }

    class ZZ {
        // private to force bridging
        private int four() { return 4; }
    }

    static int count = 0;
    ZZ azz = new ZZ();

    static void assertEqual(int expected, int got) {
        if (got != expected)
            throw new AssertionError("Expected " + expected + " got " + got);
    }

    public static void main(String[] args) {
       new MethodRefSingleRefEvalBridge().test();
    }

    ZZ check() {
        count++;
        return azz;
    }

    void test() {
       count = 0;
       SAM s = check()::four;
       assertEqual(1, count);

       count = 0;
       assertEqual(4, s.m());
       assertEqual(0, count);
    }
}