com.opensymphony.module.sitemesh.util
Class CharArrayReader

java.lang.Object
  extended by java.io.Reader
      extended by com.opensymphony.module.sitemesh.util.CharArrayReader
All Implemented Interfaces:
java.io.Closeable, java.lang.Readable

public class CharArrayReader
extends java.io.Reader

This class implements a character buffer that can be used as a character-input stream. Modified from the JDK source in that it gets rid of the ensureOpen() method, so we get unexpected behaviour if the reader is closed.

The second modification is that since this class is used internally by FastPageParser in a single thread, we don't need any locking or synchronization. Using this class instead of the standard CharArrayReader improves FastPageParser performance by 15-20%.

Author:
Hani Suleiman

Field Summary
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 inherited from class java.io.Reader
lock
 
Constructor Summary
CharArrayReader(char[] buf)
          Create an CharArrayReader from the specified array of chars.
CharArrayReader(char[] buf, int offset, int length)
          Create an CharArrayReader from the specified array of chars.
 
Method Summary
 void close()
          Close the stream.
 void mark(int readAheadLimit)
          Mark the present position in the stream.
 boolean markSupported()
          Tell whether this stream supports the mark() operation, which it does.
 int read()
          Read a single character.
 int read(char[] b, int off, int len)
          Read characters into a portion of an array.
 boolean ready()
          Tell whether this stream is ready to be read.
 void reset()
          Reset the stream to the most recent mark, or to the beginning if it has never been marked.
 long skip(long n)
          Skip characters.
 
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
 

Field Detail

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 not valid data at or beyond this index.

Constructor Detail

CharArrayReader

public CharArrayReader(char[] buf)
Create an CharArrayReader from the specified array of chars.

Parameters:
buf - Input buffer (not copied)

CharArrayReader

public CharArrayReader(char[] buf,
                       int offset,
                       int length)
Create an CharArrayReader from the specified array of chars.

Parameters:
buf - Input buffer (not copied)
offset - Offset of the first char to read
length - Number of chars to read
Method Detail

read

public int read()
         throws java.io.IOException
Read a single character.

Overrides:
read in class java.io.Reader
Throws:
java.io.IOException - If an I/O error occurs

read

public int read(char[] b,
                int off,
                int len)
         throws java.io.IOException
Read characters into a portion of an array.

Specified by:
read in class java.io.Reader
Parameters:
b - Destination buffer
off - Offset at which to start storing characters
len - Maximum number of characters to read
Returns:
The actual number of characters read, or -1 if the end of the stream has been reached
Throws:
java.io.IOException - If an I/O error occurs

skip

public long skip(long n)
          throws java.io.IOException
Skip characters.

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

ready

public boolean ready()
              throws java.io.IOException
Tell whether this stream is ready to be read. Character-array readers are always ready to be read.

Overrides:
ready in class java.io.Reader
Throws:
java.io.IOException - If an I/O error occurs

markSupported

public boolean markSupported()
Tell whether this stream supports the mark() operation, which it does.

Overrides:
markSupported in class java.io.Reader

mark

public void mark(int readAheadLimit)
          throws java.io.IOException
Mark the present position in the stream. Subsequent calls to reset() will reposition the stream to this point.

Overrides:
mark in class java.io.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:
java.io.IOException - If an I/O error occurs

reset

public void reset()
           throws java.io.IOException
Reset the stream to the most recent mark, or to the beginning if it has never been marked.

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

close

public void close()
Close the stream.

Specified by:
close in interface java.io.Closeable
Specified by:
close in class java.io.Reader

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