Class DelegatingInputStream
- java.lang.Object
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- java.io.InputStream
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- org.eclipse.net4j.util.io.DelegatingInputStream
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- All Implemented Interfaces:
java.io.Closeable
,java.lang.AutoCloseable
- Direct Known Subclasses:
XORInputStream
public class DelegatingInputStream extends java.io.InputStream
ADelegatingInputStream
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 classDelegatingInputStream
itself simply overrides all (see note below) methods ofInputStream
with versions that pass all requests to the contained input stream. Subclasses ofDelegatingInputStream
may further override some of these methods and may also provide additional methods and fields.Note: The only difference to
FilterInputStream
is thatDelegatingInputStream
does not overrideInputStream.read(byte[])
orInputStream.read(byte[], int, int)
but rather exposes the original implementations ofInputStream
which callread()
instead of their delegate counterparts.- Author:
- Eike Stepper
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Field Summary
Fields Modifier and Type Field Description protected java.io.InputStream
in
The input stream to be filtered.
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Constructor Summary
Constructors Modifier Constructor Description protected
DelegatingInputStream(java.io.InputStream in)
Creates aDelegatingInputStream
by assigning the argumentin
to the fieldthis.in
so as to remember it for later use.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description int
available()
Returns the number of bytes that can be read from this input stream without blocking.void
close()
Closes this input stream and releases any system resources associated with the stream.java.io.InputStream
getDelegate()
void
mark(int readlimit)
Marks the current position in this input stream.boolean
markSupported()
Tests if this input stream supports themark
andreset
methods.int
read()
Reads the next byte of data from this input stream.void
reset()
Repositions this stream to the position at the time themark
method was last called on this input stream.long
skip(long n)
Skips over and discardsn
bytes of data from the input stream.
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Constructor Detail
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DelegatingInputStream
protected DelegatingInputStream(java.io.InputStream in)
Creates aDelegatingInputStream
by assigning the argumentin
to the fieldthis.in
so as to remember it for later use.- Parameters:
in
- the underlying input stream, ornull
if this instance is to be created without an underlying stream.
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Method Detail
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getDelegate
public java.io.InputStream getDelegate()
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read
public int read() throws java.io.IOException
Reads the next byte of data from this input stream. The value byte is returned as anint
in the range0
to255
. If no byte is available because the end of the stream has been reached, the value-1
is 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:
read
in classjava.io.InputStream
- Returns:
- the next byte of data, or
-1
if the end of the stream is reached. - Throws:
java.io.IOException
- if an I/O error occurs.- See Also:
in
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skip
public long skip(long n) throws java.io.IOException
Skips over and discardsn
bytes of data from the input stream. Theskip
method 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:
skip
in classjava.io.InputStream
- Parameters:
n
- the number of bytes to be skipped.- Returns:
- the actual number of bytes skipped.
- Throws:
java.io.IOException
- if an I/O error occurs.
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available
public int available() throws java.io.IOException
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:
available
in classjava.io.InputStream
- Returns:
- the number of bytes that can be read from the input stream without blocking.
- Throws:
java.io.IOException
- if an I/O error occurs.- See Also:
in
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close
public void close() throws java.io.IOException
Closes this input stream and releases any system resources associated with the stream. This method simply performsin.close()
.- Specified by:
close
in interfacejava.lang.AutoCloseable
- Specified by:
close
in interfacejava.io.Closeable
- Overrides:
close
in classjava.io.InputStream
- Throws:
java.io.IOException
- if an I/O error occurs.- See Also:
in
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mark
public void mark(int readlimit)
Marks the current position in this input stream. A subsequent call to thereset
method repositions this stream at the last marked position so that subsequent reads re-read the same bytes.The
readlimit
argument 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)
.
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reset
public void reset() throws java.io.IOException
Repositions this stream to the position at the time themark
method 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.
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markSupported
public boolean markSupported()
Tests if this input stream supports themark
andreset
methods. This method simply performsin.markSupported()
.- Overrides:
markSupported
in classjava.io.InputStream
- Returns:
true
if this stream type supports themark
andreset
method;false
otherwise.- See Also:
in
,InputStream.mark(int)
,InputStream.reset()
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