BufferedInputStream

public class BufferedInputStream
extends FilterInputStream

java.lang.Object
   ↳ java.io.InputStream
     ↳ java.io.FilterInputStream
       ↳ java.io.BufferedInputStream


A BufferedInputStream adds functionality to another input stream-namely, the ability to buffer the input and to support the mark and reset methods. When the BufferedInputStream is created, an internal buffer array is created. As bytes from the stream are read or skipped, the internal buffer is refilled as necessary from the contained input stream, many bytes at a time. The mark operation remembers a point in the input stream and the reset operation causes all the bytes read since the most recent mark operation to be reread before new bytes are taken from the contained input stream.

Summary

Fields

protected byte[] buf

The internal buffer array where the data is stored.

protected int count

The index one greater than the index of the last valid byte in the buffer.

protected int marklimit

The maximum read ahead allowed after a call to the mark method before subsequent calls to the reset method fail.

protected int markpos

The value of the pos field at the time the last mark method was called.

protected int pos

The current position in the buffer.

Inherited fields

protected InputStream in

The input stream to be filtered.

Public constructors

BufferedInputStream(InputStream in)

Creates a BufferedInputStream and saves its argument, the input stream in, for later use.

BufferedInputStream(InputStream in, int size)

Creates a BufferedInputStream with the specified buffer size, and saves its argument, the input stream in, for later use.

Public methods

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.

void mark(int readlimit)

See the general contract of the mark method of InputStream.

boolean markSupported()

Tests if this input stream supports the mark and reset methods.

int read()

See the general contract of the read method of InputStream.

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

Reads bytes from this byte-input stream into the specified byte array, starting at the given offset.

void reset()

See the general contract of the reset method of InputStream.

long skip(long n)

See the general contract of the skip method of InputStream.

Inherited methods

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 caller of a method for this input stream.

void close()

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

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.

int read()

Reads the next byte of data from this input stream.

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

Reads up to len bytes of data from this input stream into an array of bytes.

int read(byte[] b)

Reads up to b.length bytes of data from this input stream into an array of bytes.

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 the input stream.

int available()

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking, which may be 0, or 0 when end of stream is detected.

void close()

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

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.

static InputStream nullInputStream()

Returns a new InputStream that reads no bytes.

int read(byte[] b)

Reads some number of bytes from the input stream and stores them into the buffer array b.

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.

byte[] readAllBytes()

Reads all remaining bytes from the input stream.

int readNBytes(byte[] b, int off, int len)

Reads the requested number of bytes from the input stream into the given byte array.

byte[] readNBytes(int len)

Reads up to a specified number of bytes from the input stream.

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.

void skipNBytes(long n)

Skips over and discards exactly n bytes of data from this input stream.

long transferTo(OutputStream out)

Reads all bytes from this input stream and writes the bytes to the given output stream in the order that they are read.

Object clone()

Creates and returns a copy of this object.

boolean equals(Object obj)

Indicates whether some other object is "equal to" this one.

void finalize()

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.

final Class<?> getClass()

Returns the runtime class of this Object.

int hashCode()

Returns a hash code value for the object.

final void notify()

Wakes up a single thread that is waiting on this object's monitor.

final void notifyAll()

Wakes up all threads that are waiting on this object's monitor.

String toString()

Returns a string representation of the object.

final void wait(long timeoutMillis, int nanos)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

final void wait(long timeoutMillis)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

final void wait()

Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

abstract void close()

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

abstract void close()

Closes this resource, relinquishing any underlying resources.

Fields

buf

Added in API level 1
protected byte[] buf

The internal buffer array where the data is stored. When necessary, it may be replaced by another array of a different size.

count

Added in API level 1
protected int count

The index one greater than the index of the last valid byte in the buffer. This value is always in the range 0 through buf.length; elements buf[0] through buf[count-1] contain buffered input data obtained from the underlying input stream.

marklimit

Added in API level 1
protected int marklimit

The maximum read ahead allowed after a call to the mark method before subsequent calls to the reset method fail. Whenever the difference between pos and markpos exceeds marklimit, then the mark may be dropped by setting markpos to -1.

See also:

markpos

Added in API level 1
protected int markpos

The value of the pos field at the time the last mark method was called.

This value is always in the range -1 through pos. If there is no marked position in the input stream, this field is -1. If there is a marked position in the input stream, then buf[markpos] is the first byte to be supplied as input after a reset operation. If markpos is not -1, then all bytes from positions buf[markpos] through buf[pos-1] must remain in the buffer array (though they may be moved to another place in the buffer array, with suitable adjustments to the values of count, pos, and markpos); they may not be discarded unless and until the difference between pos and markpos exceeds marklimit.

See also:

pos

Added in API level 1
protected int pos

The current position in the buffer. This is the index of the next character to be read from the buf array.

This value is always in the range 0 through count. If it is less than count, then buf[pos] is the next byte to be supplied as input; if it is equal to count, then the next read or skip operation will require more bytes to be read from the contained input stream.

See also:

Public constructors

BufferedInputStream

Added in API level 1
public BufferedInputStream (InputStream in)

Creates a BufferedInputStream and saves its argument, the input stream in, for later use. An internal buffer array is created and stored in buf.

Parameters
in InputStream: the underlying input stream.

BufferedInputStream

Added in API level 1
public BufferedInputStream (InputStream in, 
                int size)

Creates a BufferedInputStream with the specified buffer size, and saves its argument, the input stream in, for later use. An internal buffer array of length size is created and stored in buf.

Parameters
in InputStream: the underlying input stream.

size int: the buffer size.

Throws
IllegalArgumentException if size <= 0.

Public methods

available

Added in API level 1
public 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. The next invocation might be the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.

This method returns the sum of the number of bytes remaining to be read in the buffer (count - pos) and the result of calling the in.available().

Returns
int an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking.

Throws
IOException if this input stream has been closed by invoking its close() method, or an I/O error occurs.

close

Added in API level 1
public void close ()

Closes this input stream and releases any system resources associated with the stream. Once the stream has been closed, further read(), available(), reset(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect.

Throws
IOException if an I/O error occurs.

mark

Added in API level 1
public void mark (int readlimit)

See the general contract of the mark method of InputStream.

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

See also:

markSupported

Added in API level 1
public boolean markSupported ()

Tests if this input stream supports the mark and reset methods. The markSupported method of BufferedInputStream returns true.

Returns
boolean a boolean indicating if this stream type supports the mark and reset methods.

read

Added in API level 1
public int read ()

See the general contract of the read method of InputStream.

Returns
int the next byte of data, or -1 if the end of the stream is reached.

Throws
IOException if this input stream has been closed by invoking its close() method, or an I/O error occurs.

read

Added in API level 1
public int read (byte[] b, 
                int off, 
                int len)

Reads bytes from this byte-input stream into the specified byte array, starting at the given offset.

This method implements the general contract of the corresponding read method of the InputStream class. As an additional convenience, it attempts to read as many bytes as possible by repeatedly invoking the read method of the underlying stream. This iterated read continues until one of the following conditions becomes true:

  • The specified number of bytes have been read,
  • The read method of the underlying stream returns -1, indicating end-of-file, or
  • The available method of the underlying stream returns zero, indicating that further input requests would block.
If the first read on the underlying stream returns -1 to indicate end-of-file then this method returns -1. Otherwise this method returns the number of bytes actually read.

Subclasses of this class are encouraged, but not required, to attempt to read as many bytes as possible in the same fashion.

Parameters
b byte: destination buffer.

off int: offset at which to start storing bytes.

len int: maximum number of bytes to read.

Returns
int the number of bytes read, or -1 if the end of the stream has been reached.

Throws
IOException if this input stream has been closed by invoking its close() method, or an I/O error occurs.

reset

Added in API level 1
public void reset ()

See the general contract of the reset method of InputStream.

If markpos is -1 (no mark has been set or the mark has been invalidated), an IOException is thrown. Otherwise, pos is set equal to markpos.

Throws
IOException if this stream has not been marked or, if the mark has been invalidated, or the stream has been closed by invoking its close() method, or an I/O error occurs.

See also:

skip

Added in API level 1
public long skip (long n)

See the general contract of the skip method of InputStream.

Parameters
n long: the number of bytes to be skipped.

Returns
long the actual number of bytes skipped.

Throws
IOException if this input stream has been closed by invoking its close() method, in.skip(n) throws an IOException, or an I/O error occurs.