Class StringReader

All Implemented Interfaces:
Closeable, AutoCloseable, Readable 
public class StringReader
extends Reader

A character stream whose source is a string.

Since:
1.1

Fields

Fields declared in class java.io.Reader

lock

Constructors

Constructor Description
StringReader​(String s)

Creates a new string reader.

Methods

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 of the string if it has never been marked.
long skip​(long ns)

Skips the specified number of characters in the stream.

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

Constructors

StringReader

public StringReader(String s)

Creates a new string reader.

Parameters:
s - String providing the character stream.

Methods

read

public int read()
         throws IOException

Reads a single character.

Overrides:
read in class Reader
Returns:
The character read, 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.

Specified by:
read in class Reader
Parameters:
cbuf - Destination buffer
off - Offset at which to start writing 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:
IOException - If an I/O error occurs
IndexOutOfBoundsException - If an I/O error occurs

skip

public long skip(long ns)
          throws IOException

Skips the specified number of characters in the stream. Returns the number of characters that were skipped.

The ns parameter may be negative, even though the skip method of the Reader superclass throws an exception in this case. Negative values of ns cause the stream to skip backwards. Negative return values indicate a skip backwards. It is not possible to skip backwards past the beginning of the string.

If the entire string has been read or skipped, then this method has no effect and always returns 0.

Overrides:
skip in class Reader
Parameters:
ns - 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.

Overrides:
ready in class Reader
Returns:
True if the next read() is guaranteed not to block for input
Throws:
IOException - If the stream is closed

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 string, there is no actual limit, so this argument must not be negative, but is otherwise ignored.
Throws:
IllegalArgumentException - If readAheadLimit < 0
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 of the string 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(), or reset() 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/11/docs/api/java.base/java/io/StringReader.html