OpenJDK 27 · java.io.BufferedInputStream · APIdia, the JavaDoc alternative

Modifier and Type	Field and Description
protected volatile byte[]	buf The internal buffer array where the data is stored.
private static final long	BUF_OFFSET
protected int	count The index one greater than the index of the last valid byte in the buffer.
private static final int	DEFAULT_BUFFER_SIZE Hides java.io.InputStream.DEFAULT_BUFFER_SIZE.
private static final byte[]	EMPTY
private final int	initialSize
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.
private static final Unsafe	U As this class is used early during bootstrap, it's motivated to use Unsafe.compareAndSetReference instead of AtomicReferenceFieldUpdater (or VarHandles) to reduce dependencies and improve startup time.

Access	Constructor and Description
public	BufferedInputStream(InputStream the underlying input stream. in) Creates a `BufferedInputStream` and saves its argument, the input stream `in`, for later use.
public	BufferedInputStream(InputStream the underlying input stream. in, int the buffer size. size) Creates a `BufferedInputStream` with the specified buffer size, and saves its argument, the input stream `in`, for later use.

Method Summary

Modifier and Type	Method and Description
public synchronized int	Returns: an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking. available() Overrides java.io.FilterInputStream.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.
public void	close() Overrides java.io.FilterInputStream.close. Implements java.io.Closeable.close. Closes this input stream and releases any system resources associated with the stream.
private void	ensureOpen() Throws IOException if the stream is closed (buf is null).
private void	fill() Fills the buffer with more data, taking into account shuffling and other tricks for dealing with marks.
private byte[]	getBufIfOpen(boolean true to allocate if empty allocateIfEmpty) Returns the internal buffer, optionally allocating it if empty.
private byte[]	getBufIfOpen() Returns the internal buffer, allocating it if empty.
private InputStream	getInIfOpen() Check to make sure that underlying input stream has not been nulled out due to close; if not return it;
private static boolean	Returns: true if this class is trusted isTrusted(OutputStream os) Returns true if this class satisfies the following conditions: does not retain a reference to the `byte[]` does not leak a reference to the `byte[]` to non-trusted classes does not modify the contents of the `byte[]` `write()` method does not read the contents outside of the offset/length bounds
public synchronized void	mark(int the maximum limit of bytes that can be read before the mark position becomes invalid. readlimit) Overrides java.io.FilterInputStream.mark. See the general contract of the `mark` method of `InputStream`.
public boolean	Returns: a `boolean` indicating if this stream type supports the `mark` and `reset` methods. markSupported() Overrides java.io.FilterInputStream.markSupported. Tests if this input stream supports the `mark` and `reset` methods.
public synchronized int	Returns: the next byte of data, or `-1` if the end of the stream is reached. read() Overrides java.io.FilterInputStream.read. See the general contract of the `read` method of `InputStream`.
public synchronized int	Returns: the number of bytes read, or `-1` if the end of the stream has been reached. read(byte[] destination buffer. b, int offset at which to start storing bytes. off, int maximum number of bytes to read. len) Overrides java.io.FilterInputStream.read. Reads bytes from this byte-input stream into the specified byte array, starting at the given offset.
private int	read1(byte[] b, int off, int len) Read bytes into a portion of an array, reading from the underlying stream at most once if necessary.
public synchronized void	reset() Overrides java.io.FilterInputStream.reset. See the general contract of the `reset` method of `InputStream`.
public synchronized long	skip(long n) Overrides java.io.FilterInputStream.skip. See the general contract of the `skip` method of `InputStream`.
public synchronized long	transferTo(OutputStream out) Overrides java.io.InputStream.transferTo. Reads all bytes from this input stream and writes the bytes to the given output stream in the order that they are read.

Inherited from java.io.FilterInputStream:: read

Field Detail

buf	back to summary
protected volatile byte[] buf The internal buffer array where the data is stored. When necessary, it may be replaced by another array of a different size.

BUF_OFFSET	back to summary
private static final long BUF_OFFSET

count	back to summary
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.

DEFAULT_BUFFER_SIZE	back to summary
private static final int DEFAULT_BUFFER_SIZE Hides java.io.InputStream.DEFAULT_BUFFER_SIZE.

EMPTY	back to summary
private static final byte[] EMPTY

initialSize	back to summary
private final int initialSize

marklimit back to summary

marklimit	back to summary
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 `java.io.BufferedInputStream#mark(int)`, `java.io.BufferedInputStream#reset()`

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: java.io.BufferedInputStream#mark(int), java.io.BufferedInputStream#reset()

markpos back to summary

markpos	back to summary
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 `java.io.BufferedInputStream#mark(int)`, `java.io.BufferedInputStream#pos`

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: java.io.BufferedInputStream#mark(int), java.io.BufferedInputStream#pos

pos back to summary

pos	back to summary
protected int pos The current position in the buffer. This is the index of the next byte 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 `java.io.BufferedInputStream#buf`

protected int pos

The current position in the buffer. This is the index of the next byte 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: java.io.BufferedInputStream#buf

U	back to summary
private static final Unsafe U As this class is used early during bootstrap, it's motivated to use Unsafe.compareAndSetReference instead of AtomicReferenceFieldUpdater (or VarHandles) to reduce dependencies and improve startup time.

Constructor Detail

BufferedInputStream back to summary

BufferedInputStream	back to summary
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.

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 back to summary

BufferedInputStream	back to summary
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. Exceptions IllegalArgumentException: if `size <= 0`.

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.

Exceptions

IllegalArgumentException:: if size <= 0.

Method Detail

available back to summary

available	back to summary
public synchronized int available() throws IOException Overrides java.io.FilterInputStream.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. Exceptions IOException: if this input stream has been closed by invoking its `close()` method, or an I/O error occurs.

public synchronized int available() throws IOException

Overrides java.io.FilterInputStream.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.

Exceptions

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

close	back to summary
public void close() throws IOException Overrides java.io.FilterInputStream.close. Implements java.io.Closeable.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. Exceptions IOException: if an I/O error occurs.

back to summary

public void close() throws IOException

Overrides java.io.FilterInputStream.close.

Implements java.io.Closeable.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.

Exceptions

IOException:: if an I/O error occurs.

ensureOpen	back to summary
private void ensureOpen() throws IOException Throws IOException if the stream is closed (buf is null).

fill	back to summary
private void fill() throws IOException Fills the buffer with more data, taking into account shuffling and other tricks for dealing with marks. Assumes that it is being called by a synchronized method. This method also assumes that all data has already been read in, hence pos > count.

getBufIfOpen	back to summary
private byte[] getBufIfOpen(boolean allocateIfEmpty) throws IOException Returns the internal buffer, optionally allocating it if empty. Parameters allocateIfEmpty:boolean true to allocate if empty Exceptions IOException: if the stream is closed (buf is null)

getBufIfOpen

back to summary

private byte[] getBufIfOpen(boolean allocateIfEmpty) throws IOException

Returns the internal buffer, optionally allocating it if empty.

Parameters

allocateIfEmpty:boolean: true to allocate if empty

Exceptions

IOException:: if the stream is closed (buf is null)

getBufIfOpen	back to summary
private byte[] getBufIfOpen() throws IOException Returns the internal buffer, allocating it if empty. Exceptions IOException: if the stream is closed (buf is null)

getBufIfOpen

back to summary

private byte[] getBufIfOpen() throws IOException

Returns the internal buffer, allocating it if empty.

Exceptions

IOException:: if the stream is closed (buf is null)

getInIfOpen	back to summary
private InputStream getInIfOpen() throws IOException Check to make sure that underlying input stream has not been nulled out due to close; if not return it;

isTrusted back to summary

isTrusted	back to summary
private static boolean isTrusted(OutputStream os) Returns true if this class satisfies the following conditions: does not retain a reference to the `byte[]` does not leak a reference to the `byte[]` to non-trusted classes does not modify the contents of the `byte[]` `write()` method does not read the contents outside of the offset/length bounds Returns:boolean true if this class is trusted

private static boolean isTrusted(OutputStream os)

Returns true if this class satisfies the following conditions:

does not retain a reference to the byte[]
does not leak a reference to the byte[] to non-trusted classes
does not modify the contents of the byte[]
write() method does not read the contents outside of the offset/length bounds

Returns:boolean: true if this class is trusted

mark back to summary

mark	back to summary
public synchronized void mark(int readlimit) Overrides java.io.FilterInputStream.mark. 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 `java.io.BufferedInputStream#reset()`

public synchronized void mark(int readlimit)

Overrides java.io.FilterInputStream.mark.

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

java.io.BufferedInputStream#reset()

markSupported back to summary

markSupported	back to summary
public boolean markSupported() Overrides java.io.FilterInputStream.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. See Also `java.io.InputStream#mark(int)`, `java.io.InputStream#reset()`

public boolean markSupported()

Overrides java.io.FilterInputStream.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.
See Also: java.io.InputStream#mark(int), java.io.InputStream#reset()

read back to summary

read	back to summary
public synchronized int read() throws IOException Overrides java.io.FilterInputStream.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. Exceptions IOException: if this input stream has been closed by invoking its `close()` method, or an I/O error occurs. See Also `java.io.FilterInputStream#in`

public synchronized int read() throws IOException

Overrides java.io.FilterInputStream.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.

Exceptions

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

See Also

java.io.FilterInputStream#in

read back to summary

read	back to summary
public synchronized int read(byte[] b, int off, int len) throws IOException Overrides java.io.FilterInputStream.read. 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. Exceptions IOException: if this input stream has been closed by invoking its `close()` method, or an I/O error occurs. IndexOutOfBoundsException: If `off` is negative, `len` is negative, or `len` is greater than `b.length - off`

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

Overrides java.io.FilterInputStream.read.

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.

Exceptions

IOException:: if this input stream has been closed by invoking its close() method, or an I/O error occurs.
IndexOutOfBoundsException:: If off is negative, len is negative, or len is greater than b.length - off

read1	back to summary
private int read1(byte[] b, int off, int len) throws IOException Read bytes into a portion of an array, reading from the underlying stream at most once if necessary.

reset back to summary

reset	back to summary
public synchronized void reset() throws IOException Overrides java.io.FilterInputStream.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`. Exceptions 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 `java.io.BufferedInputStream#mark(int)`

public synchronized void reset() throws IOException

Overrides java.io.FilterInputStream.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.

Exceptions

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

java.io.BufferedInputStream#mark(int)

skip back to summary

skip	back to summary
public synchronized long skip(long n) throws IOException Overrides java.io.FilterInputStream.skip. See the general contract of the `skip` method of `InputStream`. Exceptions 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.

public synchronized long skip(long n) throws IOException

Overrides java.io.FilterInputStream.skip.

See the general contract of the skip method of InputStream.

Exceptions

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.

transferTo back to summary

transferTo	back to summary
public synchronized long transferTo(OutputStream out) throws IOException Overrides java.io.InputStream.transferTo. Doc from java.io.InputStream.transferTo. Reads all bytes from this input stream and writes the bytes to the given output stream in the order that they are read. On return, this input stream will be at end of stream. This method does not close either stream. This method may block indefinitely reading from the input stream, or writing to the output stream. The behavior for the case where the input and/or output stream is asynchronously closed, or the thread interrupted during the transfer, is highly input and output stream specific, and therefore not specified. If the total number of bytes transferred is greater than Long#MAX_VALUE, then `Long.MAX_VALUE` will be returned. If an I/O error occurs reading from the input stream or writing to the output stream, then it may do so after some bytes have been read or written. Consequently the input stream may not be at end of stream and one, or both, streams may be in an inconsistent state. It is strongly recommended that both streams be promptly closed if an I/O error occurs. Annotations @Override Exceptions IOException: if an I/O error occurs when reading or writing

public synchronized long transferTo(OutputStream out) throws IOException

Overrides java.io.InputStream.transferTo.

Doc from java.io.InputStream.transferTo.

Reads all bytes from this input stream and writes the bytes to the given output stream in the order that they are read. On return, this input stream will be at end of stream. This method does not close either stream.

This method may block indefinitely reading from the input stream, or writing to the output stream. The behavior for the case where the input and/or output stream is asynchronously closed, or the thread interrupted during the transfer, is highly input and output stream specific, and therefore not specified.

If the total number of bytes transferred is greater than Long#MAX_VALUE, then Long.MAX_VALUE will be returned.

If an I/O error occurs reading from the input stream or writing to the output stream, then it may do so after some bytes have been read or written. Consequently the input stream may not be at end of stream and one, or both, streams may be in an inconsistent state. It is strongly recommended that both streams be promptly closed if an I/O error occurs.

Annotations

@Override

Exceptions

IOException:: if an I/O error occurs when reading or writing

public Class BufferedInputStream

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