ByteArrayInputStream

public class ByteArrayInputStream extends InputStream

A ByteArrayInputStream contains an internal buffer that contains bytes that may be read from the stream. An internal counter keeps track of the next byte to be supplied by the read method.

Closing a ByteArrayInputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

See Also

• StringBufferInputStream

Field Summary

protected byte[]	buf	An array of bytes that was provided by the creator of the stream.
protected int	count	The index one greater than the last valid character in the input stream buffer.
protected int	mark	The currently marked position in the stream.
protected int	pos	The index of the next character to read from the input stream buffer.

Public Constructor Summary

	ByteArrayInputStream(byte[] buf) Creates a ByteArrayInputStream so that it uses buf as its buffer array.
	ByteArrayInputStream(byte[] buf, int offset, int length) Creates ByteArrayInputStream that uses buf as its buffer array.

Public Method Summary

synchronized int	available() Returns the number of remaining bytes that can be read (or skipped over) from this input stream.
void	close() Closing a ByteArrayInputStream has no effect.
void	mark(int readAheadLimit) Set the current marked position in the stream.
boolean	markSupported() Tests if this InputStream supports mark/reset.
synchronized int	read() Reads the next byte of data from this input stream.
synchronized int	read(byte[] b, int off, int len) Reads up to len bytes of data into an array of bytes from this input stream.
synchronized void	reset() Resets the buffer to the marked position.
synchronized long	skip(long n) Skips n bytes of input from this input stream.

Inherited Method Summary

From class java.io.InputStream

int	available() Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream.
void	close() Closes this input stream and releases any system resources associated with the stream.
synchronized void	mark(int readlimit) Marks the current position in this input stream.
boolean	markSupported() Tests if this input stream supports the mark and reset methods.
abstract int	read() Reads the next byte of data from the input stream.
int	read(byte[] b, int off, int len) Reads up to len bytes of data from the input stream into an array of bytes.
int	read(byte[] b) Reads some number of bytes from the input stream and stores them into the buffer array b.
synchronized void	reset() Repositions this stream to the position at the time the mark method was last called on this input stream.
long	skip(long n) Skips over and discards n bytes of data from this input stream.

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

From interface java.io.Closeable

abstract void

close() Closes this stream and releases any system resources associated with it.

From interface java.lang.AutoCloseable

abstract void

close() Closes this resource, relinquishing any underlying resources.

Fields

protected byte[] buf

An array of bytes that was provided by the creator of the stream. Elements buf[0] through buf[count-1] are the only bytes that can ever be read from the stream; element buf[pos] is the next byte to be read.

protected int count

The index one greater than the last valid character in the input stream buffer. This value should always be nonnegative and not larger than the length of buf. It is one greater than the position of the last byte within buf that can ever be read from the input stream buffer.

protected int mark

The currently marked position in the stream. ByteArrayInputStream objects are marked at position zero by default when constructed. They may be marked at another position within the buffer by the mark() method. The current buffer position is set to this point by the reset() method.

If no mark has been set, then the value of mark is the offset passed to the constructor (or 0 if the offset was not supplied).

protected int pos

The index of the next character to read from the input stream buffer. This value should always be nonnegative and not larger than the value of count. The next byte to be read from the input stream buffer will be buf[pos].

Public Constructors

public ByteArrayInputStream (byte[] buf)

Creates a ByteArrayInputStream so that it uses buf as its buffer array. The buffer array is not copied. The initial value of pos is 0 and the initial value of count is the length of buf.

Parameters

buf	the input buffer.

public ByteArrayInputStream (byte[] buf, int offset, int length)

Creates ByteArrayInputStream that uses buf as its buffer array. The initial value of pos is offset and the initial value of count is the minimum of offset+length and buf.length. The buffer array is not copied. The buffer's mark is set to the specified offset.

Parameters

buf	the input buffer.
offset	the offset in the buffer of the first byte to read.
length	the maximum number of bytes to read from the buffer.

Public Methods

public synchronized int available ()

Returns the number of remaining bytes that can be read (or skipped over) from this input stream.

The value returned is count - pos, which is the number of bytes remaining to be read from the input buffer.

Returns

• the number of remaining bytes that can be read (or skipped over) from this input stream without blocking.

public void close ()

Closing a ByteArrayInputStream has no effect. The methods in this class can be called after the stream has been closed without generating an IOException.

Throws

IOException

public void mark (int readAheadLimit)

Set the current marked position in the stream. ByteArrayInputStream objects are marked at position zero by default when constructed. They may be marked at another position within the buffer by this method.

If no mark has been set, then the value of the mark is the offset passed to the constructor (or 0 if the offset was not supplied).

Note: The readAheadLimit for this class has no meaning.

Parameters

readAheadLimit	the maximum limit of bytes that can be read before the mark position becomes invalid.

public boolean markSupported ()

Tests if this InputStream supports mark/reset. The markSupported method of ByteArrayInputStream always returns true.

Returns

• true if this stream instance supports the mark and reset methods; false otherwise.

public synchronized int read ()

Reads the next byte of data from this input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned.

This read method cannot block.

Returns

• the next byte of data, or -1 if the end of the stream has been reached.

public synchronized int read (byte[] b, int off, int len)

Reads up to len bytes of data into an array of bytes from this input stream. If pos equals count, then -1 is returned to indicate end of file. Otherwise, the number k of bytes read is equal to the smaller of len and count-pos. If k is positive, then bytes buf[pos] through buf[pos+k-1] are copied into b[off] through b[off+k-1] in the manner performed by System.arraycopy. The value k is added into pos and k is returned.

This read method cannot block.

Parameters

b	the buffer into which the data is read.
off	the start offset in the destination array b
len	the maximum number of bytes read.

Returns

• the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Throws

NullPointerException	If b is null.
IndexOutOfBoundsException	If off is negative, len is negative, or len is greater than b.length - off

public synchronized void reset ()

Resets the buffer to the marked position. The marked position is 0 unless another position was marked or an offset was specified in the constructor.

public synchronized long skip (long n)

Skips n bytes of input from this input stream. Fewer bytes might be skipped if the end of the input stream is reached. The actual number k of bytes to be skipped is equal to the smaller of n and count-pos. The value k is added into pos and k is returned.

Parameters

n	the number of bytes to be skipped.

Returns

• the actual number of bytes skipped.