Class BufferedInputStream

java.io.BufferedInputStream

All Implemented Interfaces:: Closeable, AutoCloseable

public class BufferedInputStream extends FilterInputStream

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.

API Note:: Once wrapped in a BufferedInputStream, the underlying InputStream should not be used directly nor wrapped with another stream.
Since:: 1.0

Field Summary

Modifier and Type	Field	Description
`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.

Fields declared in class FilterInputStream

in

Modifier and Type	Field	Description
`protected InputStream`	`in`	The input stream to be filtered.

Constructor Summary

Constructor	Description
`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.

Method Summary

Modifier and Type	Method	Description
`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`.

Methods declared in class FilterInputStream

read

Modifier and Type	Method	Description
`int`	`read(byte[] b)`	Reads up to `b.length` bytes of data from this input stream into an array of bytes.

Methods declared in class InputStream

nullInputStream, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo

Modifier and Type	Method	Description
`static InputStream`	`nullInputStream()`	Returns a new `InputStream` that reads no 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`	`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.

Methods declared in class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Modifier and Type	Method	Description
`protected Object`	`clone()`	Creates and returns a copy of this object.
`boolean`	`equals(Object obj)`	Indicates whether some other object is "equal to" this one.
`protected void`	`finalize()`	Deprecated, for removal: This API element is subject to removal in a future version. Finalization is deprecated and subject to removal in a future release.
`final Class<?>`	`getClass()`	Returns the runtime class of this `Object`.
`int`	`hashCode()`	Returns a hash code value for this 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()`	Causes the current thread to wait until it is awakened, typically by being notified or interrupted.
`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(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.

Field Details

buf

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.

count

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.

pos

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:

markpos

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:

marklimit

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:

Constructor Details

BufferedInputStream

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 - the underlying input stream.

BufferedInputStream

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 - the underlying input stream.; size - the buffer size.
Throws:: IllegalArgumentException - if size <= 0.

Method Details

read

public int read() throws IOException

See the general contract of the read method of InputStream.

Overrides:

read in class FilterInputStream

Returns:

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.

See Also:

read

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

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.

Overrides:

read in class FilterInputStream

Parameters:

b - destination buffer.

off - offset at which to start storing bytes.

len - maximum number of bytes to read.

Returns:

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.

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

See Also:

skip

public long skip(long n) throws IOException

See the general contract of the skip method of InputStream.

Overrides:

skip in class FilterInputStream

Parameters:

n - the number of bytes to be skipped.

Returns:

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.

See Also:

available

public int available() throws IOException

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().

Overrides:: available in class FilterInputStream
Returns:: 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.

mark

public void mark(int readlimit)

See the general contract of the mark method of InputStream.

Overrides:

mark in class FilterInputStream

Parameters:

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

See Also:

reset

public void reset() throws IOException

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.

Overrides:

reset in class FilterInputStream

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:

markSupported

public boolean markSupported()

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

Overrides:

markSupported in class FilterInputStream

Returns:

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

See Also:

close

public void close() throws IOException

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.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Overrides:

close in class FilterInputStream

Throws:

IOException - if an I/O error occurs.

See Also:

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