8191706: Add Reader::transferTo(Writer)
Reviewed-by: alanb, bpb, briangoetz
This commit is contained in:
Patrick Reinhart
Brian Burkhalter
parent
a53a1b7844
commit
5eafe731b0
@ -1,5 +1,5 @@
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/*
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* Copyright (c) 1996, 2012, Oracle and/or its affiliates. All rights reserved.
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* Copyright (c) 1996, 2017, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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@ -26,6 +26,8 @@
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package java.io;
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import java.util.Objects;
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/**
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* Abstract class for reading character streams. The only methods that a
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* subclass must implement are read(char[], int, int) and close(). Most
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@ -50,6 +52,8 @@ package java.io;
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public abstract class Reader implements Readable, Closeable {
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private static final int TRANSFER_BUFFER_SIZE = 8192;
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/**
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* The object used to synchronize operations on this stream. For
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* efficiency, a character-stream object may use an object other than
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@ -262,4 +266,41 @@ public abstract class Reader implements Readable, Closeable {
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*/
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public abstract void close() throws IOException;
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/**
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* Reads all characters from this reader and writes the characters to the
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* given writer in the order that they are read. On return, this reader
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* will be at end of the stream. This method does not close either reader
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* or writer.
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* <p>
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* This method may block indefinitely reading from the reader, or
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* writing to the writer. The behavior for the case where the reader
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* and/or writer is <i>asynchronously closed</i>, or the thread
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* interrupted during the transfer, is highly reader and writer
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* specific, and therefore not specified.
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* <p>
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* If an I/O error occurs reading from the reader or writing to the
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* writer, then it may do so after some characters have been read or
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* written. Consequently the reader may not be at end of the stream and
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* one, or both, streams may be in an inconsistent state. It is strongly
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* recommended that both streams be promptly closed if an I/O error occurs.
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*
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* @param out the writer, non-null
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* @return the number of characters transferred
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* @throws IOException if an I/O error occurs when reading or writing
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* @throws NullPointerException if {@code out} is {@code null}
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*
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* @since 10
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*/
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public long transferTo(Writer out) throws IOException {
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Objects.requireNonNull(out, "out");
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long transferred = 0;
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char[] buffer = new char[TRANSFER_BUFFER_SIZE];
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int nRead;
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while ((nRead = read(buffer, 0, TRANSFER_BUFFER_SIZE)) >= 0) {
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out.write(buffer, 0, nRead);
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transferred += nRead;
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}
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return transferred;
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}
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}
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353
test/jdk/java/io/Reader/TransferTo.java
Normal file
353
test/jdk/java/io/Reader/TransferTo.java
Normal file
@ -0,0 +1,353 @@
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/*
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* Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed source the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included source the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklsource St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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import java.io.*;
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import java.util.Arrays;
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import java.util.Random;
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import jdk.test.lib.RandomFactory;
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import static java.lang.String.format;
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/*
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* @test
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* @bug 8191706
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* @summary tests whether java.io.Reader.transferTo conforms to its
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* contract defined source the javadoc
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* @library /test/lib
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* @build jdk.test.lib.RandomFactory
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* @run main TransferTo
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* @key randomness
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* @author Patrick Reinhart
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*/
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public class TransferTo {
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private static Random generator = RandomFactory.getRandom();
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public static void main(String[] args) throws IOException {
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ifOutIsNullThenNpeIsThrown();
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ifExceptionInInputNeitherStreamIsClosed();
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ifExceptionInOutputNeitherStreamIsClosed();
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onReturnNeitherStreamIsClosed();
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onReturnInputIsAtEnd();
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contents();
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}
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private static void ifOutIsNullThenNpeIsThrown() throws IOException {
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try (Reader in = input()) {
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assertThrowsNPE(() -> in.transferTo(null), "out");
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}
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try (Reader in = input((char) 1)) {
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assertThrowsNPE(() -> in.transferTo(null), "out");
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}
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try (Reader in = input((char) 1, (char) 2)) {
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assertThrowsNPE(() -> in.transferTo(null), "out");
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}
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Reader in = null;
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try {
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Reader fin = in = new ThrowingReader();
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// null check should precede everything else:
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// Reader shouldn't be touched if Writer is null
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assertThrowsNPE(() -> fin.transferTo(null), "out");
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} finally {
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if (in != null)
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try {
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in.close();
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} catch (IOException ignored) { }
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}
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}
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private static void ifExceptionInInputNeitherStreamIsClosed()
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throws IOException {
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transferToThenCheckIfAnyClosed(input(0, new char[]{1, 2, 3}), output());
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transferToThenCheckIfAnyClosed(input(1, new char[]{1, 2, 3}), output());
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transferToThenCheckIfAnyClosed(input(2, new char[]{1, 2, 3}), output());
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}
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private static void ifExceptionInOutputNeitherStreamIsClosed()
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throws IOException {
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transferToThenCheckIfAnyClosed(input(new char[]{1, 2, 3}), output(0));
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transferToThenCheckIfAnyClosed(input(new char[]{1, 2, 3}), output(1));
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transferToThenCheckIfAnyClosed(input(new char[]{1, 2, 3}), output(2));
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}
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private static void transferToThenCheckIfAnyClosed(Reader input,
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Writer output)
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throws IOException {
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try (CloseLoggingReader in = new CloseLoggingReader(input);
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CloseLoggingWriter out =
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new CloseLoggingWriter(output)) {
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boolean thrown = false;
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try {
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in.transferTo(out);
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} catch (IOException ignored) {
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thrown = true;
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}
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if (!thrown)
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throw new AssertionError();
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if (in.wasClosed() || out.wasClosed()) {
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throw new AssertionError();
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}
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}
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}
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private static void onReturnNeitherStreamIsClosed()
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throws IOException {
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try (CloseLoggingReader in =
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new CloseLoggingReader(input(new char[]{1, 2, 3}));
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CloseLoggingWriter out =
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new CloseLoggingWriter(output())) {
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in.transferTo(out);
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if (in.wasClosed() || out.wasClosed()) {
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throw new AssertionError();
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}
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}
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}
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private static void onReturnInputIsAtEnd() throws IOException {
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try (Reader in = input(new char[]{1, 2, 3});
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Writer out = output()) {
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in.transferTo(out);
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if (in.read() != -1) {
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throw new AssertionError();
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}
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}
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}
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private static void contents() throws IOException {
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checkTransferredContents(new char[0]);
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checkTransferredContents(createRandomChars(1024, 4096));
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// to span through several batches
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checkTransferredContents(createRandomChars(16384, 16384));
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}
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private static void checkTransferredContents(char[] chars)
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throws IOException {
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try (Reader in = input(chars);
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StringWriter out = new StringWriter()) {
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in.transferTo(out);
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char[] outChars = out.toString().toCharArray();
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if (!Arrays.equals(chars, outChars)) {
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throw new AssertionError(
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format("chars.length=%s, outChars.length=%s",
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chars.length, outChars.length));
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}
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}
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}
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private static char[] createRandomChars(int min, int maxRandomAdditive) {
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char[] chars = new char[min + generator.nextInt(maxRandomAdditive)];
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for (int index=0; index<chars.length; index++) {
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chars[index] = (char)generator.nextInt();
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}
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return chars;
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}
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private static Writer output() {
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return output(-1);
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}
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private static Writer output(int exceptionPosition) {
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return new Writer() {
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int pos;
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@Override
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public void write(int b) throws IOException {
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if (pos++ == exceptionPosition)
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throw new IOException();
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}
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@Override
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public void write(char[] chars, int off, int len) throws IOException {
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for (int i=0; i<len; i++) {
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write(chars[off + i]);
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}
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}
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@Override
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public Writer append(CharSequence csq, int start, int end) throws IOException {
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for (int i = start; i < end; i++) {
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write(csq.charAt(i));
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}
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return this;
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}
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@Override
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public void flush() throws IOException {
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}
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@Override
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public void close() throws IOException {
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}
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};
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}
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private static Reader input(char... chars) {
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return input(-1, chars);
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}
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private static Reader input(int exceptionPosition, char... chars) {
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return new Reader() {
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int pos;
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@Override
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public int read() throws IOException {
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if (pos == exceptionPosition) {
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throw new IOException();
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}
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if (pos >= chars.length)
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return -1;
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return chars[pos++];
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}
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@Override
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public int read(char[] cbuf, int off, int len) throws IOException {
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int c = read();
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if (c == -1) {
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return -1;
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}
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cbuf[off] = (char)c;
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int i = 1;
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for (; i < len ; i++) {
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c = read();
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if (c == -1) {
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break;
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}
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cbuf[off + i] = (char)c;
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}
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return i;
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}
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@Override
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public void close() throws IOException {
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}
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};
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}
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private static class ThrowingReader extends Reader {
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boolean closed;
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@Override
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public int read(char[] b, int off, int len) throws IOException {
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throw new IOException();
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}
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@Override
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public void close() throws IOException {
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if (!closed) {
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closed = true;
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throw new IOException();
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}
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}
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@Override
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public int read() throws IOException {
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throw new IOException();
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}
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}
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private static class CloseLoggingReader extends FilterReader {
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boolean closed;
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CloseLoggingReader(Reader in) {
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super(in);
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}
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@Override
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public void close() throws IOException {
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closed = true;
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super.close();
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}
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boolean wasClosed() {
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return closed;
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}
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}
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private static class CloseLoggingWriter extends FilterWriter {
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boolean closed;
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CloseLoggingWriter(Writer out) {
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super(out);
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}
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@Override
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public void close() throws IOException {
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closed = true;
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super.close();
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}
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boolean wasClosed() {
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return closed;
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}
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}
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public interface Thrower {
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public void run() throws Throwable;
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}
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public static void assertThrowsNPE(Thrower thrower, String message) {
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assertThrows(thrower, NullPointerException.class, message);
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}
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public static <T extends Throwable> void assertThrows(Thrower thrower,
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Class<T> throwable,
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String message) {
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Throwable thrown;
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try {
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thrower.run();
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thrown = null;
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} catch (Throwable caught) {
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thrown = caught;
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}
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if (!throwable.isInstance(thrown)) {
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String caught = thrown == null ?
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"nothing" : thrown.getClass().getCanonicalName();
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throw new AssertionError(
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format("Expected to catch %s, but caught %s",
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throwable, caught), thrown);
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}
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if (thrown != null && !message.equals(thrown.getMessage())) {
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throw new AssertionError(
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format("Expected exception message to be '%s', but it's '%s'",
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message, thrown.getMessage()));
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}
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}
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}
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