1 /* 2 * Copyright (c) 2018, 2019, 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 * @bug 8206986 27 * @summary Check fall through in switch expressions. 28 * @compile --enable-preview -source ${jdk.version} ExpressionSwitchFallThrough.java 29 * @run main/othervm --enable-preview ExpressionSwitchFallThrough 30 */ 31 32 import java.util.Objects; 33 import java.util.function.Function; 34 35 public class ExpressionSwitchFallThrough { 36 public static void main(String... args) { 37 new ExpressionSwitchFallThrough().run(); 38 } 39 40 private void run() { 41 runTest(this::expression1); 42 runTest(this::expression2); 43 } 44 45 private void runTest(Function<T, String> print) { 46 check(T.A, print, "ab"); 47 check(T.B, print, "b"); 48 check(T.C, print, ""); 49 } 50 51 private String expression1(T t) { 52 String help = ""; 53 return switch (t) { 54 case A: help = "a"; 55 case B: help += "b"; 56 default: yield help; 57 }; 58 } 59 60 private String expression2(T t) { 61 String help = ""; 62 return switch (t) { 63 case A: help = "a"; 64 case B: help += "b"; 65 default: yield help; 66 }; 67 } 68 69 private void check(T t, Function<T, String> print, String expected) { 70 String result = print.apply(t); 71 if (!Objects.equals(result, expected)) { 72 throw new AssertionError("Unexpected result: " + result); 73 } 74 } 75 76 enum T { 77 A, B, C; 78 } 79 }