1 /*
   2  * Copyright (c) 2017, 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 source 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 source 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 Franklsource 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 import java.io.IOException;
  25 import java.io.StringWriter;
  26 import java.nio.BufferOverflowException;
  27 import java.nio.CharBuffer;
  28 import java.nio.ReadOnlyBufferException;
  29 import java.util.Objects;
  30 import java.util.function.Supplier;
  31 
  32 import static java.lang.String.format;
  33 
  34 /*
  35  * @test
  36  * @bug 8066870
  37  * @summary tests whether java.nio.CharBuffer.transferTo conforms to its
  38  *          contract defined source the javadoc
  39  * @author Patrick Reinhart
  40  */
  41 public class TransferTo {
  42 
  43     public static void main(String[] args) throws IOException {
  44         ifOutIsNullThenNpeIsThrown();
  45         ifOutIsSelfThenIllegalAccessExceptionIsThrown();
  46         targetIsAppendable();
  47         targetIsCharBuffer();
  48         targetIsTooSmallCharBuffer();
  49         targetIsReadOnlyCharBuffer();
  50     }
  51 
  52     private static void ifOutIsNullThenNpeIsThrown() {
  53         CharBuffer source = createSource();
  54         assertThrowsNPE(() -> source.transferTo(null), "out");
  55     }
  56 
  57     private static void ifOutIsSelfThenIllegalAccessExceptionIsThrown() {
  58         CharBuffer source = createSource();
  59         assertThrows(() -> source.transferTo(source), IllegalArgumentException.class, "Illegal transfer of a buffer to itself");
  60     }
  61 
  62     private static void targetIsAppendable() throws IOException {
  63         CharBuffer source = createSource();
  64         StringWriter target = new StringWriter();
  65         source.transferTo(target);
  66         assertEquals(source, () -> target.toString());
  67     }
  68 
  69     private static void targetIsCharBuffer() throws IOException {
  70         CharBuffer source = createSource();
  71         CharBuffer target = CharBuffer.allocate(source.limit());
  72         source.transferTo(target);
  73         assertEquals(source, () -> {
  74             target.rewind();
  75             return target.toString();
  76         });
  77     }
  78 
  79     private static void targetIsTooSmallCharBuffer() {
  80         CharBuffer source = createSource();
  81         CharBuffer target = CharBuffer.allocate(source.limit() - 1);
  82         assertThrows(() -> source.transferTo(target), BufferOverflowException.class, null);
  83     }
  84 
  85     private static void targetIsReadOnlyCharBuffer() {
  86         CharBuffer source = createSource();
  87         CharBuffer target = CharBuffer.allocate(source.limit()).asReadOnlyBuffer();
  88         assertThrows(() -> source.transferTo(target), ReadOnlyBufferException.class, null);
  89     }
  90 
  91     private static CharBuffer createSource() {
  92         CharBuffer buffer = CharBuffer.wrap("mary had a little lamb");
  93         buffer.rewind();
  94         return buffer;
  95     }
  96 
  97     private static void assertEquals(CharBuffer expected, Supplier<String> testValueSupplier) {
  98         expected.rewind();
  99         String correct = expected.toString();
 100         String tested = testValueSupplier.get();
 101         if (!correct.equals(tested)) {
 102             throw new AssertionError(format("Expected: '%s', but got '%s'", correct, tested));
 103         }
 104     }
 105 
 106     public interface Thrower {
 107         public void run() throws Throwable;
 108     }
 109 
 110     public static void assertThrowsNPE(Thrower thrower, String message) {
 111         assertThrows(thrower, NullPointerException.class, message);
 112     }
 113 
 114     public static <T extends Throwable> void assertThrows(Thrower thrower,
 115                                                           Class<T> throwable,
 116                                                           String message) {
 117         Throwable thrown;
 118         try {
 119             thrower.run();
 120             thrown = null;
 121         } catch (Throwable caught) {
 122             thrown = caught;
 123         }
 124 
 125         if (!throwable.isInstance(thrown)) {
 126             String caught = thrown == null ?
 127                     "nothing" : thrown.getClass().getCanonicalName();
 128             throw new AssertionError(
 129                     format("Expected to catch %s, but caught %s",
 130                             throwable, caught), thrown);
 131         }
 132 
 133         if (thrown != null && !Objects.equals(message, thrown.getMessage())) {
 134             throw new AssertionError(
 135                     format("Expected exception message to be '%s', but it's '%s'",
 136                             message, thrown.getMessage()));
 137         }
 138     }
 139 }