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8341566: Add Reader.of(CharSequence)

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Reviewed-by: rriggs, jpai, liach, alanb
This commit is contained in:
Markus KARG 2024-10-24 14:34:58 +00:00 • committed by Chen Liang
parent b0ac633b2d
commit 3c14c2babb
3 changed files with 349 additions and 47 deletions
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115
src/java.base/share/classes/java/io/Reader.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1996, 2023, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1996, 2024, 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
@ -140,6 +140,119 @@ public abstract class Reader implements Readable, Closeable {
};
}
/**
* Returns a {@code Reader} that reads characters from a
* {@code CharSequence}. The reader is initially open and reading starts at
* the first character in the sequence.
*
* <p> The returned reader supports the {@link #mark mark()} and
* {@link #reset reset()} operations.
*
* <p> The resulting reader is not safe for use by multiple
* concurrent threads. If the reader is to be used by more than one
* thread it should be controlled by appropriate synchronization.
*
* <p> If the sequence changes while the reader is open, e.g. the length
* changes, the behavior is undefined.
*
* @param cs {@code CharSequence} providing the character stream.
* @return a {@code Reader} which reads characters from {@code cs}
* @throws NullPointerException if {@code cs} is {@code null}
*
* @since 24
*/
public static Reader of(final CharSequence cs) {
Objects.requireNonNull(cs);
return new Reader() {
private boolean isClosed;
private int next = 0;
private int mark = 0;
/** Check to make sure that the stream has not been closed */
private void ensureOpen() throws IOException {
if (isClosed)
throw new IOException("Stream closed");
}
@Override
public int read() throws IOException {
ensureOpen();
if (next >= cs.length())
return -1;
return cs.charAt(next++);
}
@Override
public int read(char[] cbuf, int off, int len) throws IOException {
ensureOpen();
Objects.checkFromIndexSize(off, len, cbuf.length);
if (len == 0) {
return 0;
}
int length = cs.length();
if (next >= length)
return -1;
int n = Math.min(length - next, len);
switch (cs) {
case String s -> s.getChars(next, next + n, cbuf, off);
case StringBuilder sb -> sb.getChars(next, next + n, cbuf, off);
case StringBuffer sb -> sb.getChars(next, next + n, cbuf, off);
case CharBuffer cb -> cb.get(next, cbuf, off, n);
default -> {
for (int i = 0; i < n; i++)
cbuf[off + i] = cs.charAt(next + i);
}
}
next += n;
return n;
}
@Override
public long skip(long n) throws IOException {
ensureOpen();
if (next >= cs.length())
return 0;
// Bound skip by beginning and end of the source
long r = Math.min(cs.length() - next, n);
r = Math.max(-next, r);
next += (int)r;
return r;
}
@Override
public boolean ready() throws IOException {
ensureOpen();
return true;
}
@Override
public boolean markSupported() {
return true;
}
@Override
public void mark(int readAheadLimit) throws IOException {
if (readAheadLimit < 0){
throw new IllegalArgumentException("Read-ahead limit < 0");
}
ensureOpen();
mark = next;
}
@Override
public void reset() throws IOException {
ensureOpen();
next = mark;
}
@Override
public void close() {
isClosed = true;
}
};
}
/**
* The object used to synchronize operations on this stream. For
* efficiency, a character-stream object may use an object other than

64
src/java.base/share/classes/java/io/StringReader.java
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1996, 2023, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1996, 2024, 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
@ -30,16 +30,17 @@ import java.util.Objects;
/**
* A character stream whose source is a string.
*
* @apiNote
* {@link Reader#of(CharSequence)} provides a method to read from any
* {@link CharSequence} that may be more efficient than {@code StringReader}.
*
* @author Mark Reinhold
* @since 1.1
*/
public class StringReader extends Reader {
private final int length;
private String str;
private int next = 0;
private int mark = 0;
private final Reader r;
/**
* Creates a new string reader.
@ -47,14 +48,7 @@ public class StringReader extends Reader {
* @param s String providing the character stream.
*/
public StringReader(String s) {
this.length = s.length();
this.str = s;
}
/** Check to make sure that the stream has not been closed */
private void ensureOpen() throws IOException {
if (str == null)
throw new IOException("Stream closed");
r = Reader.of(s);
}
/**
@ -67,10 +61,7 @@ public class StringReader extends Reader {
*/
public int read() throws IOException {
synchronized (lock) {
ensureOpen();
if (next >= length)
return -1;
return str.charAt(next++);
return r.read();
}
}
@ -94,17 +85,7 @@ public class StringReader extends Reader {
*/
public int read(char[] cbuf, int off, int len) throws IOException {
synchronized (lock) {
ensureOpen();
Objects.checkFromIndexSize(off, len, cbuf.length);
if (len == 0) {
return 0;
}
if (next >= length)
return -1;
int n = Math.min(length - next, len);
str.getChars(next, next + n, cbuf, off);
next += n;
return n;
return r.read(cbuf, off, len);
}
}
@ -130,14 +111,7 @@ public class StringReader extends Reader {
*/
public long skip(long n) throws IOException {
synchronized (lock) {
ensureOpen();
if (next >= length)
return 0;
// Bound skip by beginning and end of the source
long r = Math.min(length - next, n);
r = Math.max(-next, r);
next += (int)r;
return r;
return r.skip(n);
}
}
@ -150,8 +124,7 @@ public class StringReader extends Reader {
*/
public boolean ready() throws IOException {
synchronized (lock) {
ensureOpen();
return true;
return r.ready();
}
}
@ -176,12 +149,8 @@ public class StringReader extends Reader {
* @throws IOException If an I/O error occurs
*/
public void mark(int readAheadLimit) throws IOException {
if (readAheadLimit < 0){
throw new IllegalArgumentException("Read-ahead limit < 0");
}
synchronized (lock) {
ensureOpen();
mark = next;
r.mark(readAheadLimit);
}
}
@ -193,8 +162,7 @@ public class StringReader extends Reader {
*/
public void reset() throws IOException {
synchronized (lock) {
ensureOpen();
next = mark;
r.reset();
}
}
@ -207,7 +175,11 @@ public class StringReader extends Reader {
*/
public void close() {
synchronized (lock) {
str = null;
try {
r.close();
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
}
}

217
test/jdk/java/io/Reader/Of.java Normal file
View file

@ -0,0 +1,217 @@
/*
* Copyright (c) 2024, 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.
*/
import java.io.Reader;
import java.io.StringReader;
import java.io.IOException;
import java.io.StringWriter;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.ReadOnlyBufferException;
import org.testng.annotations.*;
import static org.testng.Assert.*;
/*
* @test
* @bug 8341566
* @summary Check for expected behavior of Reader.of().
* @run testng Of
*/
public class Of {
final static String CONTENT = "Some Reader Test";
/*
* Readers to be tested.
*/
@DataProvider
public static Reader[] readers() {
return new Reader[] {
new StringReader(CONTENT),
Reader.of(CONTENT),
Reader.of(new StringBuffer(CONTENT)),
Reader.of(new StringBuilder(CONTENT)),
Reader.of(ByteBuffer.allocateDirect(CONTENT.length() * 2)
.asCharBuffer().put(CONTENT).flip()),
Reader.of(CharBuffer.wrap(CONTENT.toCharArray())),
Reader.of(new CharSequence() {
@Override
public char charAt(int index) {
return CONTENT.charAt(index);
}
@Override
public int length() {
return CONTENT.length();
}
@Override
public CharSequence subSequence(int start, int end) {
// unused by Reader.Of's result
throw new UnsupportedOperationException();
}
@Override
public String toString() {
// Reader.Of's result SHALL NOT convert to String
throw new UnsupportedOperationException();
}
})
};
}
@Test(dataProvider = "readers")
public void testRead(Reader reader) throws IOException {
String s = "";
for (int c; (c = reader.read()) != -1; s += (char) c);
assertEquals(s, CONTENT, "read() returned wrong value");
}
@Test(dataProvider = "readers")
public void testReadBII(Reader reader) throws IOException {
char[] c = new char[16];
assertEquals(reader.read(c, 8, 8), 8,
"read(char[],int,int) does not respect given start or end");
assertEquals(reader.read(c, 0, 16), 8,
"read(char[],int,int) does not respect end of stream");
assertEquals(new String(c),
CONTENT.substring(8, 16) + CONTENT.substring(0, 8),
"read(char[],int,int) provides wrong content");
}
@Test(dataProvider = "readers")
public void testReadBIILenZero(Reader reader) throws IOException {
assertEquals(reader.read(new char[1], 0, 0), 0,
"read(char[],int,int) != 0");
}
@Test(dataProvider = "readers")
public void testReadDirectCharBuffer(Reader reader) throws IOException {
CharBuffer charBuffer = ByteBuffer.allocateDirect(32).asCharBuffer();
charBuffer.position(8);
assertEquals(reader.read(charBuffer), 8,
"read(CharBuffer) does not respect position or limit");
charBuffer.rewind();
assertEquals(reader.read(charBuffer), 8,
"read(CharBuffer) does not respect end of stream");
charBuffer.rewind();
assertEquals(charBuffer.toString(),
// last part first proofs that copy loops correctly stopped
CONTENT.substring(8, 16) + CONTENT.substring(0, 8),
"read(CharBuffer) provides wrong content");
}
@Test(dataProvider = "readers")
public void testReadNonDirectCharBuffer(Reader reader) throws IOException {
CharBuffer charBuffer = CharBuffer.allocate(16);
charBuffer.position(8);
assertEquals(reader.read(charBuffer), 8,
"read(CharBuffer) does not respect position or limit");
charBuffer.rewind();
assertEquals(reader.read(charBuffer), 8,
"read(CharBuffer) does not respect end of stream");
charBuffer.rewind();
assertEquals(charBuffer.toString(),
CONTENT.substring(8, 16) + CONTENT.substring(0, 8),
"read(CharBuffer) provides wrong content");
}
@Test(dataProvider = "readers")
public void testReadCharBufferZeroRemaining(Reader reader) throws IOException {
CharBuffer charBuffer = CharBuffer.allocate(0);
assertEquals(reader.read(charBuffer), 0, "read(CharBuffer) != 0");
}
@Test(dataProvider = "readers")
public void testReady(Reader reader) throws IOException {
assertTrue(reader.ready());
}
@Test(dataProvider = "readers")
public void testSkip(Reader reader) throws IOException {
assertEquals(reader.skip(8), 8, "skip() does not respect limit");
assertEquals(reader.skip(9), 8, "skip() does not respect end of stream");
assertEquals(reader.skip(1), 0, "skip() does not respect empty stream");
}
@Test(dataProvider = "readers")
public void testTransferTo(Reader reader) throws IOException {
StringWriter sw = new StringWriter(16);
assertEquals(reader.transferTo(sw), 16, "transferTo() != 16");
assertEquals(reader.transferTo(sw), 0,
"transferTo() does not respect empty stream");
assertEquals(sw.toString(), CONTENT,
"transferTo() provides wrong content");
}
@Test(dataProvider = "readers")
public void testReadClosed(Reader reader) throws IOException {
reader.close();
assertThrows(IOException.class, () -> {reader.read();});
}
@Test(dataProvider = "readers")
public void testReadBIIClosed(Reader reader) throws IOException {
reader.close();
assertThrows(IOException.class, () -> reader.read(new char[1], 0, 1));
}
@Test(dataProvider = "readers")
public void testReadCharBufferClosed(Reader reader) throws IOException {
CharBuffer charBuffer = CharBuffer.allocate(1);
reader.close();
assertThrows(IOException.class, () -> reader.read(charBuffer));
}
@Test(dataProvider = "readers")
public void testReadCharBufferZeroRemainingClosed(Reader reader) throws IOException {
CharBuffer charBuffer = CharBuffer.allocate(0);
reader.close();
assertThrows(IOException.class, () -> reader.read(charBuffer));
}
@Test(dataProvider = "readers")
public void testReadyClosed(Reader reader) throws IOException {
reader.close();
assertThrows(IOException.class, () -> reader.ready());
}
@Test(dataProvider = "readers")
public void testSkipClosed(Reader reader) throws IOException {
reader.close();
assertThrows(IOException.class, () -> reader.skip(1));
}
@Test(dataProvider = "readers")
public void testTransferToClosed(Reader reader) throws IOException {
reader.close();
assertThrows(IOException.class, () -> reader.transferTo(new StringWriter(1)));
}
@Test(dataProvider = "readers")
public void testCloseClosed(Reader reader) throws IOException {
reader.close();
reader.close();
}
}