Java™ Platform
Standard Ed. 6

java.io
Class StringReader

java.lang.Object
  extended by java.io.Reader
      extended by java.io.StringReader
All Implemented Interfaces:
Closeable, Readable

public class StringReader
extends Reader

A character stream whose source is a string.

Since:
JDK1.1

Field Summary
 
Fields inherited from class java.io.Reader
lock
 
Constructor Summary
StringReader(String s)
          Creates a new string reader.
 
Method Summary
 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 inherited from class java.io.Reader
read, read
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

StringReader

public StringReader(String s)
Creates a new string reader.

Parameters:
s - String providing the character stream.
Method Detail

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

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 is < 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.

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

Java™ Platform
Standard Ed. 6

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For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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