java.io

Class FilterInputStream

Implemented Interfaces:
AutoCloseable, Closeable
Known Direct Subclasses:
BufferedInputStream, CheckedInputStream, CipherInputStream, DataInputStream, DigestInputStream, InflaterInputStream, LineNumberInputStream, ProgressMonitorInputStream, PushbackInputStream

public class FilterInputStream
extends InputStream

This is the common superclass of all standard classes that filter input. It acts as a layer on top of an underlying InputStream and simply redirects calls made to it to the subordinate InputStream instead. Subclasses of this class perform additional filtering functions in addition to simply redirecting the call.

This class is not abstract. However, since it only redirects calls to a subordinate InputStream without adding any functionality on top of it, this class should not be used directly. Instead, various subclasses of this class should be used. This is enforced with a protected constructor. Do not try to hack around it.

When creating a subclass of FilterInputStream, override the appropriate methods to implement the desired filtering. However, note that the read(byte[]) method does not need to be overridden as this class redirects calls to that method to read(byte[], int, int) instead of to the subordinate InputStream read(byte[]) method.

Field Summary

protected InputStream
in
This is the subordinate InputStream to which method calls are redirected

Constructor Summary

FilterInputStream(InputStream in)
Create a FilterInputStream with the specified subordinate InputStream.

Method Summary

int
available()
Calls the in.available() method.
void
close()
This method closes the input stream by closing the input stream that this object is filtering.
void
mark(int readlimit)
Calls the in.mark(int) method.
boolean
markSupported()
Calls the in.markSupported() method.
int
read()
Calls the in.read() method
int
read(byte[] buf)
Calls the read(byte[], int, int) overloaded method.
int
read(byte[] buf, int offset, int len)
Calls the in.read(byte[], int, int) method.
void
reset()
Calls the in.reset() method.
long
skip(long numBytes)
Calls the in.skip(long) method

Methods inherited from class java.io.InputStream

available, close, mark, markSupported, read, read, read, reset, skip

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

in

protected InputStream in
This is the subordinate InputStream to which method calls are redirected

Constructor Details

FilterInputStream

protected FilterInputStream(InputStream in)
Create a FilterInputStream with the specified subordinate InputStream.
Parameters:
in - The subordinate InputStream

Method Details

available

public int available()
            throws IOException
Calls the in.available() method.
Overrides:
available in interface InputStream
Returns:
The value returned from in.available()
Throws:
IOException - If an error occurs

close

public void close()
            throws IOException
This method closes the input stream by closing the input stream that this object is filtering. Future attempts to access this stream may throw an exception.
Specified by:
close in interface Closeable
close in interface AutoCloseable
Overrides:
close in interface InputStream
Throws:
IOException - If an error occurs

mark

public void mark(int readlimit)
Calls the in.mark(int) method.
Overrides:
mark in interface InputStream
Parameters:
readlimit - The parameter passed to in.mark(int)

markSupported

public boolean markSupported()
Calls the in.markSupported() method.
Overrides:
markSupported in interface InputStream
Returns:
true if mark/reset is supported, false otherwise

read

public int read()
            throws IOException
Calls the in.read() method
Overrides:
read in interface InputStream
Returns:
The value returned from in.read()
Throws:
IOException - If an error occurs

read

public int read(byte[] buf)
            throws IOException
Calls the read(byte[], int, int) overloaded method. Note that this method does not redirect its call directly to a corresponding method in in. This allows subclasses to override only the three argument version of read.
Overrides:
read in interface InputStream
Parameters:
buf - The buffer to read bytes into
Returns:
The value retured from in.read(byte[], int, int)
Throws:
IOException - If an error occurs

read

public int read(byte[] buf,
                int offset,
                int len)
            throws IOException
Calls the in.read(byte[], int, int) method.
Overrides:
read in interface InputStream
Parameters:
buf - The buffer to read bytes into
offset - The index into the buffer to start storing bytes
len - The maximum number of bytes to read.
Returns:
The value retured from in.read(byte[], int, int)
Throws:
IOException - If an error occurs

reset

public void reset()
            throws IOException
Calls the in.reset() method.
Overrides:
reset in interface InputStream
Throws:
IOException - If an error occurs

skip

public long skip(long numBytes)
            throws IOException
Calls the in.skip(long) method
Overrides:
skip in interface InputStream
Parameters:
numBytes - The requested number of bytes to skip.
Returns:
The value returned from in.skip(long)
Throws:
IOException - If an error occurs

FilterInputStream.java -- Base class for classes that filter input Copyright (C) 1998, 1999, 2001, 2005 Free Software Foundation, Inc. This file is part of GNU Classpath. GNU Classpath is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNU Classpath is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNU Classpath; see the file COPYING. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. Linking this library statically or dynamically with other modules is making a combined work based on this library. Thus, the terms and conditions of the GNU General Public License cover the whole combination. As a special exception, the copyright holders of this library give you permission to link this library with independent modules to produce an executable, regardless of the license terms of these independent modules, and to copy and distribute the resulting executable under terms of your choice, provided that you also meet, for each linked independent module, the terms and conditions of the license of that module. An independent module is a module which is not derived from or based on this library. If you modify this library, you may extend this exception to your version of the library, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version.