public class

ByteArrayInputStream

extends InputStream
java.lang.Object
   ↳ java.io.InputStream
     ↳ java.io.ByteArrayInputStream

Class Overview

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.

Summary

Fields
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 Constructors
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 Methods
synchronized int available()
Returns the number of bytes that can be read from this input stream without blocking.
synchronized void close()
Closes this input stream and releases any system resources associated with the stream.
void mark(int readAheadLimit)
Set the current marked position in the stream.
boolean markSupported()
Tests if ByteArrayInputStream 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.
[Expand]
Inherited Methods
From class java.io.InputStream
From class java.lang.Object

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.

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 offset+length. The buffer array is not copied.

Note that if bytes are simply read from the resulting input stream, elements buf[pos] through buf[pos+len-1] will be read; however, if a reset operation is performed, then bytes buf[0] through buf[pos-1] will then become available for input.

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 bytes that can be read from this input stream without blocking. The value returned is count - pos, which is the number of bytes remaining to be read from the input buffer.

Returns
  • the number of bytes that can be read from the input stream without blocking.

public synchronized void close ()

Closes this input stream and releases any system resources associated with the stream.

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.

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

public boolean markSupported ()

Tests if ByteArrayInputStream supports mark/reset.

Returns
  • true if this true type supports the mark and reset method; 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 of the data.
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.

public synchronized void reset ()

Resets the buffer to the marked position. The marked position is the beginning unless another position was marked. The value of pos is set to 0.

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.