duke@1: /*
ohair@554:  * Copyright (c) 2002, Oracle and/or its affiliates. All rights reserved.
duke@1:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@1:  *
duke@1:  * This code is free software; you can redistribute it and/or modify it
duke@1:  * under the terms of the GNU General Public License version 2 only, as
duke@1:  * published by the Free Software Foundation.
duke@1:  *
duke@1:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@1:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@1:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@1:  * version 2 for more details (a copy is included in the LICENSE file that
duke@1:  * accompanied this code).
duke@1:  *
duke@1:  * You should have received a copy of the GNU General Public License version
duke@1:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@1:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@1:  *
ohair@554:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
ohair@554:  * or visit www.oracle.com if you need additional information or have any
ohair@554:  * questions.
duke@1:  */
duke@1: 
duke@1: /*
duke@1:  * @test
duke@1:  * @bug 4509267
duke@1:  * @summary generics: parametric exception type versus overriding
duke@1:  * @author gafter
duke@1:  *
darcy@289:  * @compile  ParametricException.java
duke@1:  */
duke@1: 
duke@1: import java.io.*;
duke@1: 
duke@1: abstract class AChurchBoolean {
duke@1:     public abstract <Return, Parameter, Throws extends Throwable>
duke@1:     Return accept(IVisitor<Return, Parameter, Throws> visitor, Parameter parameter) throws Throws;
duke@1: 
duke@1:     public interface IVisitor<Return, Parameter, Throws extends Throwable> {
duke@1:         public Return caseTrue(Parameter parameter) throws Throws;
duke@1:         public Return caseFalse(Parameter parameter) throws Throws;
duke@1:     }
duke@1: }
duke@1: 
duke@1: class TrueChurchBoolean extends AChurchBoolean {
duke@1:     private static TrueChurchBoolean instance = new TrueChurchBoolean();
duke@1:     private TrueChurchBoolean() {}
duke@1:     public static TrueChurchBoolean singleton() {
duke@1:         return instance;
duke@1:     }
duke@1:     public <Return, Parameter, Throws extends Throwable>
duke@1:     Return accept(IVisitor<Return, Parameter, Throws> visitor, Parameter parameter) throws Throws {
duke@1:         return visitor.caseTrue(parameter);
duke@1:     }
duke@1: }
duke@1: 
duke@1: class FalseChurchBoolean extends AChurchBoolean {
duke@1:     private static FalseChurchBoolean instance = new FalseChurchBoolean();
duke@1:     private FalseChurchBoolean() {}
duke@1:     public static FalseChurchBoolean singleton() {
duke@1:         return instance;
duke@1:     }
duke@1:     public <Return, Parameter, Throws extends Throwable>
duke@1:     Return accept(IVisitor<Return, Parameter, Throws> visitor, Parameter parameter) throws Throws {
duke@1:         return visitor.caseFalse(parameter);
duke@1:     }
duke@1: }
duke@1: 
duke@1: class Pair<T,U> {
duke@1:     private T first;
duke@1:     private U second;
duke@1:     Pair(T first, U second) {
duke@1:         this.first = first;
duke@1:         this.second = second;
duke@1:     }
duke@1:     T getFirst() {
duke@1:         return first;
duke@1:     }
duke@1:     U getSecond() {
duke@1:         return second;
duke@1:     }
duke@1: }
duke@1: 
duke@1: // Perhaps a bit of a toy example, but relevant nonetheless.
duke@1: class ChurchBooleanTest {
duke@1:     private AChurchBoolean bool;
duke@1:     public ChurchBooleanTest(AChurchBoolean bool) {
duke@1:         this.bool = bool;
duke@1:     }
duke@1:     public AChurchBoolean readIf(File file, byte[] output) throws IOException {
duke@1:         return bool.accept(new AChurchBoolean.IVisitor<AChurchBoolean, Pair<File, byte[]>, IOException>() {
duke@1:             public AChurchBoolean caseTrue(Pair<File, byte[]> parameter) throws IOException {
duke@1:                 FileInputStream input = new FileInputStream(parameter.getFirst()); // throws
duke@1:                 input.read(parameter.getSecond()); // throws
duke@1:                 input.close(); // throws
duke@1:                 return TrueChurchBoolean.singleton();
duke@1:             }
duke@1:             public AChurchBoolean caseFalse(Pair<File, byte[]> parameter) throws IOException {
duke@1:                 return FalseChurchBoolean.singleton();
duke@1:             }
duke@1:         }, new Pair<File, byte[]>(file, output));
duke@1:     }
duke@1: }