Class CharArrayReader

protected char[] buf

The array that contains the data supplied during read operations

protected int count

This indicates the maximum number of chars that can be read from this stream. It is the array index of the position after the last valid char in the buffer buf

protected int markedPos

The currently marked position in the stream. This defaults to 0, so a reset operation on the stream resets it to read from array index 0 in the buffer - even if the stream was initially created with an offset greater than 0

protected int pos

The array index of the next char to be read from the buffer buf

public CharArrayReader(char[] buffer)

Create a new CharArrayReader that will read chars from the passed in char array. This stream will read from the beginning to the end of the array. It is identical to calling an overloaded constructor as CharArrayReader(buf, 0, buf.length).

Note that this array is not copied. If its contents are changed while this stream is being read, those changes will be reflected in the chars supplied to the reader. Please use caution in changing the contents of the buffer while this stream is open.

Parameters:

buffer - The char array buffer this stream will read from.

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

Create a new CharArrayReader that will read chars from the passed in char array. This stream will read from position offset in the array for a length of length chars past offset. If the stream is reset to a position before offset then more than length chars can be read from the stream. The length value should be viewed as the array index one greater than the last position in the buffer to read.

Note that this array is not copied. If its contents are changed while this stream is being read, those changes will be reflected in the chars supplied to the reader. Please use caution in changing the contents of the buffer while this stream is open.

Parameters:

buffer - The char array buffer this stream will read from.

offset - The index into the buffer to start reading chars from

length - The number of chars to read from the buffer

public void close()

This method closes the stream.

Specified by:

close in interface Closeable

Overrides:

close in interface Reader

public void mark(int readAheadLimit)
            throws IOException

This method sets the mark position in this stream to the current position. Note that the readlimit parameter in this method does nothing as this stream is always capable of remembering all the chars int it.

Note that in this class the mark position is set by default to position 0 in the stream. This is in constrast to some other stream types where there is no default mark position.

Overrides:

mark in interface Reader

Parameters:

readAheadLimit - The number of chars this stream must remember. This parameter is ignored.

Throws:

IOException - If an error occurs

public boolean markSupported()

This method overrides the markSupported method in Reader in order to return true - indicating that this stream class supports mark/reset functionality.

Overrides:

markSupported in interface Reader

Returns:

true to indicate that this class supports mark/reset.

public int read()
            throws IOException

This method reads one char from the stream. The pos counter is advanced to the next char to be read. The char read is returned as an int in the range of 0-65535. If the stream position is already at the end of the buffer, no char is read and a -1 is returned in order to indicate the end of the stream.

Overrides:

read in interface Reader

Returns:

The char read, or -1 if end of stream

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

This method reads chars from the stream and stores them into a caller supplied buffer. It starts storing the data at index offset into the buffer and attempts to read len chars. This method can return before reading the number of chars requested if the end of the stream is encountered first. The actual number of chars read is returned. If no chars can be read because the stream is already at the end of stream position, a -1 is returned.

This method does not block.

Parameters:

b - The array into which the chars read should be stored.

off - The offset into the array to start storing chars

len - The requested number of chars to read

Returns:

The actual number of chars read, or -1 if end of stream.

public boolean ready()
            throws IOException

Return true if more characters are available to be read.

Overrides:

ready in interface Reader

Returns:

true to indicate that this stream is ready to be read.

public void reset()
            throws IOException

This method sets the read position in the stream to the mark point by setting the pos variable equal to the mark variable. Since a mark can be set anywhere in the array, the mark/reset methods int this class can be used to provide random search capabilities for this type of stream.

Overrides:

reset in interface Reader

public long skip(long n)
            throws IOException

This method attempts to skip the requested number of chars in the input stream. It does this by advancing the pos value by the specified number of chars. It this would exceed the length of the buffer, then only enough chars are skipped to position the stream at the end of the buffer. The actual number of chars skipped is returned.

Overrides:

skip in interface Reader

Parameters:

n - The requested number of chars to skip

Returns:

The actual number of chars skipped.