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 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 * @test

 * @bug 8206986

 * @summary Ensure CaseTree methods return expected values

 * @modules jdk.compiler

 */

import java.io.IOException;

import java.io.StringWriter;

import java.net.URI;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import java.util.stream.Collectors;

import javax.tools.*;

import com.sun.source.tree.CaseTree;

import com.sun.source.tree.CompilationUnitTree;

import com.sun.source.tree.Tree;

import com.sun.source.util.JavacTask;

import com.sun.source.util.TreePathScanner;

public class CaseTest {

    public static void main(String[] args) throws Exception {

        new CaseTest().testLabels();

        new CaseTest().testStatement();

        new CaseTest().testRule();

    }

    void testLabels() throws Exception {

        String code = "class Test {\n" +

                      "    void t(int i) {\n" +

                      "         switch(i) {\n" +

                      "              case 0: break;\n" +

                      "              case 1, 2: breal;\n" +

                      "              default: breal;\n" +

                      "         }\n" +

                      "    }\n" +

                      "}\n";

        List<String> labels = new ArrayList<>();

        new TreePathScanner<Void, Void>() {

            @Override

            public Void visitCase(CaseTree node, Void p) {

                labels.add(String.valueOf(node.getExpression()));

                labels.add(node.getExpressions().stream()

                                                .map(String::valueOf)

                                                .collect(Collectors.joining(",", "[", "]")));

                return super.visitCase(node, p);

            }

        }.scan(parse(code), null);

        List<String> expected = Arrays.asList("0", "[0]", "1", "[1,2]", "null", "[]");

        if (!expected.equals(labels)) {

            throw new AssertionError("Unexpected labels found: " + labels);

        }

    }

    void testStatement() throws Exception {

        String code = "class Test {\n" +

                      "    void t(int i) {\n" +

                      "         switch(i) {\n" +

                      "              case 0:" +

                      "                  System.err.println();\n" +

                      "                  break;\n" +

                      "         }\n" +

                      "    }\n" +

                      "}\n";

        new TreePathScanner<Void, Void>() {

            @Override

            public Void visitCase(CaseTree node, Void p) {

                if (node.getStatements().size() != 2) {

                    throw new AssertionError("Unexpected statements: " + node.getStatements());

                }

                if (node.getBody() != null) {

                    throw new AssertionError("Unexpected body: " + node.getBody());

                }

                return super.visitCase(node, p);

            }

        }.scan(parse(code), null);

    }

    void testRule() throws Exception {

        String code = "class Test {\n" +

                      "    void t(int i) {\n" +

                      "         switch(i) {\n" +

                      "              case 0 -> {" +

                      "                  System.err.println();\n" +

                      "              };\n" +

                      "         }\n" +

                      "    }\n" +

                      "}\n";

        new TreePathScanner<Void, Void>() {

            @Override

            public Void visitCase(CaseTree node, Void p) {

                if (node.getStatements() != null) {

                    throw new AssertionError("Unexpected statements: " + node.getStatements());

                }

                if (node.getBody().getKind() != Tree.Kind.BLOCK) {

                    throw new AssertionError("Unexpected body: " + node.getBody());

                }

                return super.visitCase(node, p);

            }

        }.scan(parse(code), null);

    }

    private CompilationUnitTree parse(String code) throws IOException {

        final JavaCompiler tool = ToolProvider.getSystemJavaCompiler();

        assert tool != null;

        DiagnosticListener<JavaFileObject> noErrors = d -> {};

        StringWriter out = new StringWriter();

        JavacTask ct = (JavacTask) tool.getTask(out, null, noErrors,

            Arrays.asList(new MyFileObject(code)));

        return ct.parse().iterator().next();

    }

    static class MyFileObject extends SimpleJavaFileObject {

        private String text;

        public MyFileObject(String text) {

            super(URI.create("myfo:/Test.java"), JavaFileObject.Kind.SOURCE);

            this.text = text;

        }

        @Override

        public CharSequence getCharContent(boolean ignoreEncodingErrors) {

            return text;

        }

    }

}