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Java Fundamental Classes Reference

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The java.io Package
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StringReader

Name

StringReader

Synopsis

Class Name:

java.io.StringReader

Superclass:

java.io.Reader

Immediate Subclasses:

None

Interfaces Implemented:

None

Availability:

New as of JDK 1.1

Description

The StringReader class represents a character stream whose data source is a String. This class is similar to the CharArrayReader class, which uses a char array as its data source.

StringReader is meant to replace the StringBufferInputStream class as of JDK 1.1. Unlike StringBufferInputStream, StringReader handles Unicode characters and supports mark() and reset().

Class Summary

public class java.io.StringReader extends java.io.Reader {
  // Constructors
  public StringReader(String s);
  // Instance Methods
  public void close();
  public void mark(int readAheadLimit);
  public boolean markSupported();
  public int read();
  public int read(char[] cbuf, int off, int len);
  public boolean ready();
  public void reset();
  public long skip(long ns);
}

Constructors

StringReader

public StringReader(String s)

Parameters

s

The String to use.

Description

This constructor creates a StringReader that uses the given String as its data source. The data is not copied, so changes made to the String affect the data that the StringReader returns.

Instance Methods

close

public void close()

Overrides

Reader.close()

Description

This method closes the reader by removing the link between this StringReader and the String it was created with.

mark

public void mark(int readAheadLimit) throws IOException

Parameters

readAheadLimit

The maximum number of characters that can be read before the saved position becomes invalid.

Throws

IOException

If the stream is closed or any other kind of I/O error occurs.

Overrides

Reader.mark()

Description

This method causes the StringReader to remember its current position. A subsequent call to reset() causes the object to return to that saved position, and thus re-read a portion of the string. Because the data for this stream comes from a String, there is no limit on reading ahead, so readAheadLimit is ignored.

markSupported

public boolean markSupported()

Returns

The boolean value true.

Overrides

Reader.markSupported()

Description

This method returns true to indicate that this class supports mark() and reset().

read

public int read() throws IOException

Returns

The next character or -1 if the end of the string is encountered.

Throws

IOException

If the stream is closed or any other kind of I/O error occurs.

Overrides

Reader.read()

Description

This method returns the next character from the string. The method cannot block.

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

Parameters

cbuf

An array of characters to be filled from the stream.

off

An offset into the character array.

len

The number of characters to read.

Returns

The actual number of characters read or -1 if the end of the string is encountered immediately.

Throws

IOException

If the stream is closed or any other kind of I/O error occurs.

Overrides

Reader.read(char[], int, int)

Description

This method copies up to len characters from the internal buffer into the given array cbuf, starting at index off.

ready

public boolean ready() throws IOException

Returns

A boolean value that indicates whether the stream is ready to be read.

Throws

IOException

If the stream is closed or any other kind of I/O error occurs.

Overrides

Reader.ready()

Description

If there is any data left to be read from the string, this method returns true.

reset

public void reset() throws IOException

Throws

IOException

If the stream is closed or any other kind of I/O error occurs.

Overrides

Reader.reset()

Description

This method resets the position of the StringReader to the position that was saved by calling the mark() method. If mark() has not been called, the StringReader is reset to read from the beginning of the string.

skip

public long skip(long ns) throws IOException

Parameters

ns

The number of bytes to skip.

Returns

The actual number of bytes skipped.

Throws

IOException

If the stream is closed or any other kind of I/O error occurs.

Overrides

Reader.skip()

Description

This method skips ns characters of input. If you try to skip past the end of the string, the stream is positioned at the end of the string.

Inherited Methods

Method

Inherited From

Method

Inherited From

clone()

Object

equals (Object)

Object

finalize()

Object

getClass()

Object

hashCode()

Object

notify()

Object

notifyAll()

Object

read(char[])

Reader

toString()

Object

wait()

Object

wait(long)

Object

wait(long, int)

Object

See Also

CharArrayReader, IOException, Reader, String, StringBufferInputStream


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