- java.lang.Object
-
- java.io.InputStream
-
- java.io.FilterInputStream
-
- All Implemented Interfaces:
- Closeable, AutoCloseable
- Direct Known Subclasses:
- BufferedInputStream, CheckedInputStream, CipherInputStream, DataInputStream, DeflaterInputStream, DigestInputStream, InflaterInputStream, LineNumberInputStream, ProgressMonitorInputStream, PushbackInputStream
public class FilterInputStream extends InputStream
AFilterInputStream
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 classFilterInputStream
itself simply overrides all methods ofInputStream
with versions that pass all requests to the contained input stream. Subclasses ofFilterInputStream
may further override some of these methods and may also provide additional methods and fields.- Since:
- JDK1.0
-
-
Field Summary
Fields Modifier and Type Field and Description protected InputStream
in
The input stream to be filtered.
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Constructor Summary
Constructors Modifier Constructor and Description protected
FilterInputStream(InputStream in)
Creates aFilterInputStream
by assigning the argumentin
to the fieldthis.in
so as to remember it for later use.
-
Method Summary
Methods Modifier and Type Method and 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 caller 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)
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.int
read(byte[] b)
Reads up tobyte.length
bytes of data from this input stream into an array of bytes.int
read(byte[] b, int off, int len)
Reads up tolen
bytes of data from this input stream into an array of bytes.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.
-
-
-
Field Detail
-
in
protected volatile InputStream in
The input stream to be filtered.
-
-
Constructor Detail
-
FilterInputStream
protected FilterInputStream(InputStream in)
Creates aFilterInputStream
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.
-
-
Method Detail
-
read
public int read() throws 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 classInputStream
- Returns:
- the next byte of data, or
-1
if the end of the stream is reached. - Throws:
IOException
- if an I/O error occurs.- See Also:
in
-
read
public int read(byte[] b) throws IOException
Reads up tobyte.length
bytes of data from this input stream into an array of bytes. This method blocks until some input is available.This method simply performs the call
read(b, 0, b.length)
and returns the result. It is important that it does not doin.read(b)
instead; certain subclasses ofFilterInputStream
depend on the implementation strategy actually used.- Overrides:
read
in classInputStream
- Parameters:
b
- the buffer into which the data is read.- Returns:
- the total number of bytes read into the buffer, or
-1
if there is no more data because the end of the stream has been reached. - Throws:
IOException
- if an I/O error occurs.- See Also:
read(byte[], int, int)
-
read
public int read(byte[] b, int off, int len) throws IOException
Reads up tolen
bytes of data from this input stream into an array of bytes. Iflen
is not zero, the method blocks until some input is available; otherwise, no bytes are read and0
is returned.This method simply performs
in.read(b, off, len)
and returns the result.- Overrides:
read
in classInputStream
- Parameters:
b
- the buffer into which the data is read.off
- the start offset in the destination arrayb
len
- the maximum number of bytes read.- Returns:
- the total number of bytes read into the buffer, or
-1
if there is no more data because the end of the stream has been reached. - Throws:
NullPointerException
- Ifb
isnull
.IndexOutOfBoundsException
- Ifoff
is negative,len
is negative, orlen
is greater thanb.length - off
IOException
- if an I/O error occurs.- See Also:
in
-
skip
public long skip(long n) throws 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 classInputStream
- Parameters:
n
- the number of bytes to be skipped.- Returns:
- the actual number of bytes skipped.
- Throws:
IOException
- if the stream does not support seek, or if some other I/O error occurs.
-
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 caller of a method for this input stream. The next caller 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 result of
in
.available().- Overrides:
available
in classInputStream
- Returns:
- an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking.
- Throws:
IOException
- if an I/O error occurs.
-
close
public void close() throws IOException
Closes this input stream and releases any system resources associated with the stream. This method simply performsin.close()
.- Specified by:
close
in interfaceCloseable
- Specified by:
close
in interfaceAutoCloseable
- Overrides:
close
in classInputStream
- Throws:
IOException
- if an I/O error occurs.- See Also:
in
-
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)
.- Overrides:
mark
in classInputStream
- Parameters:
readlimit
- the maximum limit of bytes that can be read before the mark position becomes invalid.- See Also:
in
,reset()
-
reset
public void reset() throws 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.
- Overrides:
reset
in classInputStream
- Throws:
IOException
- if the stream has not been marked or if the mark has been invalidated.- See Also:
in
,mark(int)
-
markSupported
public boolean markSupported()
Tests if this input stream supports themark
andreset
methods. This method simply performsin.markSupported()
.- Overrides:
markSupported
in classInputStream
- Returns:
true
if this stream type supports themark
andreset
method;false
otherwise.- See Also:
in
,InputStream.mark(int)
,InputStream.reset()
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Bij voorbaat dank.
Document heeft de 11/06/2005 gemaakt, de laatste keer de 04/03/2020 gewijzigd
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