jdk8-mips64-public/langtools: test/tools/javac/generics/ParametricException.java@2eb010b6cb22

     1 /*

     2  * Copyright (c) 2002, 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  */

    24 /*

    25  * @test

    26  * @bug 4509267

    27  * @summary generics: parametric exception type versus overriding

    28  * @author gafter

    29  *

    30  * @compile  ParametricException.java

    31  */

    33 import java.io.*;

    35 abstract class AChurchBoolean {

    36     public abstract <Return, Parameter, Throws extends Throwable>

    37     Return accept(IVisitor<Return, Parameter, Throws> visitor, Parameter parameter) throws Throws;

    39     public interface IVisitor<Return, Parameter, Throws extends Throwable> {

    40         public Return caseTrue(Parameter parameter) throws Throws;

    41         public Return caseFalse(Parameter parameter) throws Throws;

    42     }

    43 }

    45 class TrueChurchBoolean extends AChurchBoolean {

    46     private static TrueChurchBoolean instance = new TrueChurchBoolean();

    47     private TrueChurchBoolean() {}

    48     public static TrueChurchBoolean singleton() {

    49         return instance;

    50     }

    51     public <Return, Parameter, Throws extends Throwable>

    52     Return accept(IVisitor<Return, Parameter, Throws> visitor, Parameter parameter) throws Throws {

    53         return visitor.caseTrue(parameter);

    54     }

    55 }

    57 class FalseChurchBoolean extends AChurchBoolean {

    58     private static FalseChurchBoolean instance = new FalseChurchBoolean();

    59     private FalseChurchBoolean() {}

    60     public static FalseChurchBoolean singleton() {

    61         return instance;

    62     }

    63     public <Return, Parameter, Throws extends Throwable>

    64     Return accept(IVisitor<Return, Parameter, Throws> visitor, Parameter parameter) throws Throws {

    65         return visitor.caseFalse(parameter);

    66     }

    67 }

    69 class Pair<T,U> {

    70     private T first;

    71     private U second;

    72     Pair(T first, U second) {

    73         this.first = first;

    74         this.second = second;

    75     }

    76     T getFirst() {

    77         return first;

    78     }

    79     U getSecond() {

    80         return second;

    81     }

    82 }

    84 // Perhaps a bit of a toy example, but relevant nonetheless.

    85 class ChurchBooleanTest {

    86     private AChurchBoolean bool;

    87     public ChurchBooleanTest(AChurchBoolean bool) {

    88         this.bool = bool;

    89     }

    90     public AChurchBoolean readIf(File file, byte[] output) throws IOException {

    91         return bool.accept(new AChurchBoolean.IVisitor<AChurchBoolean, Pair<File, byte[]>, IOException>() {

    92             public AChurchBoolean caseTrue(Pair<File, byte[]> parameter) throws IOException {

    93                 FileInputStream input = new FileInputStream(parameter.getFirst()); // throws

    94                 input.read(parameter.getSecond()); // throws

    95                 input.close(); // throws

    96                 return TrueChurchBoolean.singleton();

    97             }

    98             public AChurchBoolean caseFalse(Pair<File, byte[]> parameter) throws IOException {

    99                 return FalseChurchBoolean.singleton();

   100             }

   101         }, new Pair<File, byte[]>(file, output));

   102     }

   103 }

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