/*

 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 * questions.

 */

/*

 * @test

 * @bug 8206986

 * @summary Check fall through in switch expressions.

 * @compile --enable-preview -source 12 ExpressionSwitchFallThrough.java

 * @run main/othervm --enable-preview ExpressionSwitchFallThrough

 */

import java.util.Objects;

import java.util.function.Function;

public class ExpressionSwitchFallThrough {

    public static void main(String... args) {

        new ExpressionSwitchFallThrough().run();

    }

    private void run() {

        runTest(this::expression1);

        runTest(this::expression2);

    }

    private void runTest(Function<T, String> print) {

        check(T.A,  print, "ab");

        check(T.B,  print, "b");

        check(T.C,  print, "");

    }

    private String expression1(T t) {

        String help = "";

        return switch (t) {

            case A: help = "a";

            case B: help += "b";

            default: break help;

        };

    }

    private String expression2(T t) {

        String help = "";

        return switch (t) {

            case A: help = "a";

            case B: help += "b";

            default: break help;

        };

    }

    private void check(T t, Function<T, String> print, String expected) {

        String result = print.apply(t);

        if (!Objects.equals(result, expected)) {

            throw new AssertionError("Unexpected result: " + result);

        }

    }

    enum T {

        A, B, C;

    }

}