public class DelegatingInputStream
extends java.io.InputStream
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.
| Modifier and Type | Field and Description |
|---|---|
protected java.io.InputStream |
in
The input stream to be filtered.
|
| Modifier | Constructor and Description |
|---|---|
protected |
DelegatingInputStream(java.io.InputStream in)
Creates a
DelegatingInputStream by assigning the argument in to the field
this.in so as to remember it for later use. |
| Modifier and Type | Method and 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 the
mark and reset methods. |
int |
read()
Reads the next byte of data from this input stream.
|
void |
reset()
Repositions this stream to the position at the time the
mark method was last called on this input
stream. |
long |
skip(long n)
Skips over and discards
n bytes of data from the input stream. |
protected DelegatingInputStream(java.io.InputStream in)
DelegatingInputStream by assigning the argument in to the field
this.in so as to remember it for later use.in - the underlying input stream, or null if this instance is to be created without an underlying
stream.public java.io.InputStream getDelegate()
public int read()
throws java.io.IOException
int in the range
0 to 255. 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.
read in class java.io.InputStream-1 if the end of the stream is reached.java.io.IOException - if an I/O error occurs.inpublic long skip(long n)
throws java.io.IOException
n bytes of data from the input stream. The skip method may, for a
variety of reasons, end up skipping over some smaller number of bytes, possibly 0. The actual number
of bytes skipped is returned.
This method simply performs in.skip(n).
skip in class java.io.InputStreamn - the number of bytes to be skipped.java.io.IOException - if an I/O error occurs.public int available()
throws java.io.IOException
This method simply performs in.available() and returns the result.
available in class java.io.InputStreamjava.io.IOException - if an I/O error occurs.inpublic void close()
throws java.io.IOException
in.close().close in interface java.io.Closeableclose in interface java.lang.AutoCloseableclose in class java.io.InputStreamjava.io.IOException - if an I/O error occurs.inpublic void mark(int readlimit)
reset 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).
public void reset()
throws java.io.IOException
mark 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.
public boolean markSupported()
mark and reset methods. This method simply
performs in.markSupported().markSupported in class java.io.InputStreamtrue if this stream type supports the mark and reset method;
false otherwise.in,
InputStream.mark(int),
InputStream.reset()Copyright (c) 2004-2019 Eike Stepper (Loehne, Germany) and others.
All rights reserved. This program and the accompanying materials are made available under the terms of the Eclipse Public License v1.0 which accompanies this distribution, and is available at http://www.eclipse.org/legal/epl-v10.html