- java.lang.Object
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- java.io.InputStream
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- java.io.FilterInputStream
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- java.io.BufferedInputStream
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- All Implemented Interfaces:
Closeable,AutoCloseable
public class BufferedInputStream extends FilterInputStream
ABufferedInputStreamadds functionality to another input stream-namely, the ability to buffer the input and to support themarkandresetmethods. When theBufferedInputStreamis 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. Themarkoperation remembers a point in the input stream and theresetoperation causes all the bytes read since the most recentmarkoperation to be reread before new bytes are taken from the contained input stream.- Since:
- 1.0
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Field Summary
Fields Modifier and Type Field Description protected byte[]bufThe internal buffer array where the data is stored.protected intcountThe index one greater than the index of the last valid byte in the buffer.protected intmarklimitThe maximum read ahead allowed after a call to themarkmethod before subsequent calls to theresetmethod fail.protected intmarkposThe value of theposfield at the time the lastmarkmethod was called.protected intposThe current position in the buffer.-
Fields declared in class java.io.FilterInputStream
in
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Constructor Summary
Constructors Constructor Description BufferedInputStream(InputStream in)Creates aBufferedInputStreamand saves its argument, the input streamin, for later use.BufferedInputStream(InputStream in, int size)Creates aBufferedInputStreamwith the specified buffer size, and saves its argument, the input streamin, for later use.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description intavailable()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.voidclose()Closes this input stream and releases any system resources associated with the stream.voidmark(int readlimit)See the general contract of themarkmethod ofInputStream.booleanmarkSupported()Tests if this input stream supports themarkandresetmethods.intread()See the general contract of thereadmethod ofInputStream.intread(byte[] b, int off, int len)Reads bytes from this byte-input stream into the specified byte array, starting at the given offset.voidreset()See the general contract of theresetmethod ofInputStream.longskip(long n)See the general contract of theskipmethod ofInputStream.-
Methods declared in class java.io.FilterInputStream
read
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Methods declared in class java.io.InputStream
nullInputStream, readAllBytes, readNBytes, readNBytes, transferTo
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Field Detail
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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.
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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 range0throughbuf.length; elementsbuf[0]throughbuf[count-1]contain buffered input data obtained from the underlying input stream.
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pos
protected int pos
The current position in the buffer. This is the index of the next character to be read from thebufarray.This value is always in the range
0throughcount. If it is less thancount, thenbuf[pos]is the next byte to be supplied as input; if it is equal tocount, then the nextreadorskipoperation will require more bytes to be read from the contained input stream.- See Also:
buf
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markpos
protected int markpos
The value of theposfield at the time the lastmarkmethod was called.This value is always in the range
-1throughpos. If there is no marked position in the input stream, this field is-1. If there is a marked position in the input stream, thenbuf[markpos]is the first byte to be supplied as input after aresetoperation. Ifmarkposis not-1, then all bytes from positionsbuf[markpos]throughbuf[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 ofcount,pos, andmarkpos); they may not be discarded unless and until the difference betweenposandmarkposexceedsmarklimit.
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Constructor Detail
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BufferedInputStream
public BufferedInputStream(InputStream in)
Creates aBufferedInputStreamand saves its argument, the input streamin, for later use. An internal buffer array is created and stored inbuf.- Parameters:
in- the underlying input stream.
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BufferedInputStream
public BufferedInputStream(InputStream in, int size)
Creates aBufferedInputStreamwith the specified buffer size, and saves its argument, the input streamin, for later use. An internal buffer array of lengthsizeis created and stored inbuf.- Parameters:
in- the underlying input stream.size- the buffer size.- Throws:
IllegalArgumentException- ifsize <= 0.
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Method Detail
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read
public int read() throws IOExceptionSee the general contract of thereadmethod ofInputStream.- Overrides:
readin classFilterInputStream- Returns:
- the next byte of data, or
-1if the end of the stream is reached. - Throws:
IOException- if this input stream has been closed by invoking itsclose()method, or an I/O error occurs.- See Also:
FilterInputStream.in
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read
public int read(byte[] b, int off, int len) throws IOExceptionReads 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
method of thereadclass. As an additional convenience, it attempts to read as many bytes as possible by repeatedly invoking theInputStreamreadmethod of the underlying stream. This iteratedreadcontinues until one of the following conditions becomes true:- The specified number of bytes have been read,
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readmethod of the underlying stream returns-1, indicating end-of-file, or - The
availablemethod of the underlying stream returns zero, indicating that further input requests would block.
readon the underlying stream returns-1to 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:
readin classFilterInputStream- 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
-1if the end of the stream has been reached. - Throws:
IOException- if this input stream has been closed by invoking itsclose()method, or an I/O error occurs.- See Also:
FilterInputStream.in
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skip
public long skip(long n) throws IOExceptionSee the general contract of theskipmethod ofInputStream.- Overrides:
skipin classFilterInputStream- 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 itsclose()method,in.skip(n)throws an IOException, or an I/O error occurs.
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available
public int available() throws IOExceptionReturns 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 thein.available().- Overrides:
availablein classFilterInputStream- 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 itsclose()method, or an I/O error occurs.
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mark
public void mark(int readlimit)
See the general contract of themarkmethod ofInputStream.- Overrides:
markin classFilterInputStream- Parameters:
readlimit- the maximum limit of bytes that can be read before the mark position becomes invalid.- See Also:
reset()
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reset
public void reset() throws IOExceptionSee the general contract of theresetmethod ofInputStream.If
markposis-1(no mark has been set or the mark has been invalidated), anIOExceptionis thrown. Otherwise,posis set equal tomarkpos.- Overrides:
resetin classFilterInputStream- Throws:
IOException- if this stream has not been marked or, if the mark has been invalidated, or the stream has been closed by invoking itsclose()method, or an I/O error occurs.- See Also:
mark(int)
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markSupported
public boolean markSupported()
Tests if this input stream supports themarkandresetmethods. ThemarkSupportedmethod ofBufferedInputStreamreturnstrue.- Overrides:
markSupportedin classFilterInputStream- Returns:
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booleanindicating if this stream type supports themarkandresetmethods. - See Also:
InputStream.mark(int),InputStream.reset()
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close
public void close() throws IOExceptionCloses 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:
closein interfaceAutoCloseable- Specified by:
closein interfaceCloseable- Overrides:
closein classFilterInputStream- Throws:
IOException- if an I/O error occurs.- See Also:
FilterInputStream.in
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