Class DelegatingInputStream
- All Implemented Interfaces:
Closeable,AutoCloseable
- Direct Known Subclasses:
XORInputStream
DelegatingInputStream contains some other input stream, which it uses as its basic source of data,
possibly transforming the data along the way or providing additional functionality. The class
DelegatingInputStream itself simply overrides all (see note below) methods of InputStream
with versions that pass all requests to the contained input stream. Subclasses of DelegatingInputStream
may further override some of these methods and may also provide additional methods and fields.
Note: The only difference to FilterInputStream is that DelegatingInputStream does
not override InputStream.read(byte[]) or InputStream.read(byte[], int, int) but rather exposes the original
implementations of InputStream which call read() instead of their delegate counterparts.
- Author:
- Eike Stepper
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Field Summary
Fields -
Constructor Summary
ConstructorsModifierConstructorDescriptionprotectedCreates aDelegatingInputStreamby assigning the argumentinto the fieldthis.inso as to remember it for later use. -
Method Summary
Modifier and TypeMethodDescriptionintReturns the number of bytes that can be read from this input stream without blocking.voidclose()Closes this input stream and releases any system resources associated with the stream.voidmark(int readlimit) Marks the current position in this input stream.booleanTests if this input stream supports themarkandresetmethods.intread()Reads the next byte of data from this input stream.voidreset()Repositions this stream to the position at the time themarkmethod was last called on this input stream.longskip(long n) Skips over and discardsnbytes of data from the input stream.Methods inherited from class java.io.InputStream
nullInputStream, read, read, readAllBytes, readNBytes, readNBytes, skipNBytes, transferTo
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Field Details
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in
The input stream to be filtered.
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Constructor Details
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DelegatingInputStream
Creates aDelegatingInputStreamby assigning the argumentinto the fieldthis.inso as to remember it for later use.- Parameters:
in- the underlying input stream, ornullif this instance is to be created without an underlying stream.
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Method Details
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getDelegate
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read
Reads the next byte of data from this input stream. The value byte is returned as anintin the range0to255. If no byte is available because the end of the stream has been reached, the value-1is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.This method simply performs
in.read()and returns the result.- Specified by:
readin classInputStream- Returns:
- the next byte of data, or
-1if the end of the stream is reached. - Throws:
IOException- if an I/O error occurs.- See Also:
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skip
Skips over and discardsnbytes of data from the input stream. Theskipmethod may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly0. The actual number of bytes skipped is returned.This method simply performs
in.skip(n).- Overrides:
skipin classInputStream- Parameters:
n- the number of bytes to be skipped.- Returns:
- the actual number of bytes skipped.
- Throws:
IOException- if an I/O error occurs.
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available
Returns the number of bytes that can be read from this input stream without blocking.This method simply performs
in.available()and returns the result.- Overrides:
availablein classInputStream- Returns:
- the number of bytes that can be read from the input stream without blocking.
- Throws:
IOException- if an I/O error occurs.- See Also:
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close
Closes this input stream and releases any system resources associated with the stream. This method simply performsin.close().- Specified by:
closein interfaceAutoCloseable- Specified by:
closein interfaceCloseable- Overrides:
closein classInputStream- Throws:
IOException- if an I/O error occurs.- See Also:
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mark
public void mark(int readlimit) Marks the current position in this input stream. A subsequent call to theresetmethod repositions this stream at the last marked position so that subsequent reads re-read the same bytes.The
readlimitargument tells this input stream to allow that many bytes to be read before the mark position gets invalidated.This method simply performs
in.mark(readlimit).- Overrides:
markin classInputStream- Parameters:
readlimit- the maximum limit of bytes that can be read before the mark position becomes invalid.- See Also:
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reset
Repositions this stream to the position at the time themarkmethod was last called on this input stream.This method simply performs
in.reset().Stream marks are intended to be used in situations where you need to read ahead a little to see what's in the stream. Often this is most easily done by invoking some general parser. If the stream is of the type handled by the parse, it just chugs along happily. If the stream is not of that type, the parser should toss an exception when it fails. If this happens within readlimit bytes, it allows the outer code to reset the stream and try another parser.
- Overrides:
resetin classInputStream- Throws:
IOException- if the stream has not been marked or if the mark has been invalidated.- See Also:
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markSupported
public boolean markSupported()Tests if this input stream supports themarkandresetmethods. This method simply performsin.markSupported().- Overrides:
markSupportedin classInputStream- Returns:
trueif this stream type supports themarkandresetmethod;falseotherwise.- See Also:
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