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Class CharArrayReader

java.lang.Object

java.io.Reader

java.io.CharArrayReader

All Implemented Interfaces:: Closeable, AutoCloseable, Readable

public class CharArrayReader extends Reader

This class implements a character buffer that can be used as a character-input stream.

Since:: 1.1

Field Summary

Modifier and Type	Field	Description
`protected char[]`	`buf`	The character buffer.
`protected int`	`count`	The index of the end of this buffer.
`protected int`	`markedPos`	The position of mark in buffer.
`protected int`	`pos`	The current buffer position.

Fields declared in class java.io.Reader

lock

Constructor Summary

Constructor	Description
`CharArrayReader(char[] buf)`	Creates a CharArrayReader from the specified array of chars.
`CharArrayReader(char[] buf, int offset, int length)`	Creates a CharArrayReader from the specified array of chars.

Method Summary

Modifier and Type	Method	Description
`void`	`close()`	Closes the stream and releases any system resources associated with it.
`void`	`mark(int readAheadLimit)`	Marks the present position in the stream.
`boolean`	`markSupported()`	Tells whether this stream supports the mark() operation, which it does.
`int`	`read()`	Reads a single character.
`int`	`read(char[] cbuf, int off, int len)`	Reads characters into a portion of an array.
`boolean`	`ready()`	Tells whether this stream is ready to be read.
`void`	`reset()`	Resets the stream to the most recent mark, or to the beginning if it has never been marked.
`long`	`skip(long n)`	Skips characters.

Methods declared in class java.io.Reader

nullReader, read, read, transferTo

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

buf

protected char[] buf

The character buffer.

pos

protected int pos

The current buffer position.

markedPos

protected int markedPos

The position of mark in buffer.

count

protected int count

The index of the end of this buffer. There is no valid data at or beyond this index.

Constructor Details

CharArrayReader

public CharArrayReader(char[] buf)

Creates a CharArrayReader from the specified array of chars.

Parameters:: buf - Input buffer (not copied)

CharArrayReader

public CharArrayReader(char[] buf, int offset, int length)

Creates a CharArrayReader from the specified array of chars.

The resulting reader will start reading at the given offset. The total number of char values that can be read from this reader will be either length or buf.length-offset, whichever is smaller.

Parameters:: buf - Input buffer (not copied); offset - Offset of the first char to read; length - Number of chars to read
Throws:: IllegalArgumentException - If offset is negative or greater than buf.length, or if length is negative, or if the sum of these two values is negative.

Method Details

read

public int read() throws IOException

Reads a single character.

Overrides:: read in class Reader
Returns:: The character read, as an integer in the range 0 to 65535 (0x00-0xffff), or -1 if the end of the stream has been reached
Throws:: IOException - If an I/O error occurs

read

public int read(char[] cbuf, int off, int len) throws IOException

Reads characters into a portion of an array.

If len is zero, then no characters are read and 0 is returned; otherwise, there is an attempt to read at least one character. If no character is available because the stream is at its end, the value -1 is returned; otherwise, at least one character is read and stored into cbuf.

Specified by:: read in class Reader
Parameters:: cbuf - Destination buffer; off - Offset at which to start storing characters; len - Maximum number of characters to read
Returns:: The number of characters read, or -1 if the end of the stream has been reached
Throws:: IndexOutOfBoundsException - If off is negative, or len is negative, or len is greater than cbuf.length - off; IOException - If an I/O error occurs

skip

public long skip(long n) throws IOException

Skips characters. If the stream is already at its end before this method is invoked, then no characters are skipped and zero is returned.

The n parameter may be negative, even though the skip method of the Reader superclass throws an exception in this case. If n is negative, then this method does nothing and returns 0.

Overrides:: skip in class Reader
Parameters:: n - The number of characters to skip
Returns:: The number of characters actually skipped
Throws:: IOException - If an I/O error occurs

ready

public boolean ready() throws IOException

Tells whether this stream is ready to be read. Character-array readers are always ready to be read.

Overrides:: ready in class Reader
Returns:: True if the next read() is guaranteed not to block for input, false otherwise. Note that returning false does not guarantee that the next read will block.
Throws:: IOException - If an I/O error occurs

markSupported

public boolean markSupported()

Tells whether this stream supports the mark() operation, which it does.

Overrides:: markSupported in class Reader
Returns:: true if and only if this stream supports the mark operation.

mark

public void mark(int readAheadLimit) throws IOException

Marks the present position in the stream. Subsequent calls to reset() will reposition the stream to this point.

Overrides:: mark in class Reader
Parameters:: readAheadLimit - Limit on the number of characters that may be read while still preserving the mark. Because the stream's input comes from a character array, there is no actual limit; hence this argument is ignored.
Throws:: IOException - If an I/O error occurs

reset

public void reset() throws IOException

Resets the stream to the most recent mark, or to the beginning if it has never been marked.

Overrides:: reset in class Reader
Throws:: IOException - If an I/O error occurs

close

public void close()

Closes the stream and releases any system resources associated with it. Once the stream has been closed, further read(), ready(), mark(), reset(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect. This method will block while there is another thread blocking on the reader.

Specified by:: close in interface AutoCloseable
Specified by:: close in interface Closeable
Specified by:: close in class Reader

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
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https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/io/CharArrayReader.html