java.io

Class FilterInputStream

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
protected	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

Field Detail

in

protected InputStream in

This is the subordinate InputStream to which method calls are redirected

Constructor Detail

FilterInputStream

protected FilterInputStream(InputStream in)

Create a FilterInputStream with the specified subordinate InputStream.

Parameters: in The subordinate InputStream

Method Detail

available

public int available()

Calls the in.available() method.

Returns: The value returned from in.available()

Throws: IOException If an error occurs

close

public void close()

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.

Throws: IOException If an error occurs

mark

public void mark(int readlimit)

Calls the in.mark(int) method.

Parameters: readlimit The parameter passed to in.mark(int)

markSupported

public boolean markSupported()

Calls the in.markSupported() method.

Returns: true if mark/reset is supported, false otherwise

read

public int read()

Calls the in.read() method

Returns: The value returned from in.read()

Throws: IOException If an error occurs

read

public int read(byte[] buf)

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.

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)

Calls the in.read(byte[], int, int) method.

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()

Calls the in.reset() method.

Throws: IOException If an error occurs

skip

public long skip(long numBytes)

Calls the in.skip(long) method

Parameters: numBytes The requested number of bytes to skip.

Returns: The value returned from in.skip(long)

Throws: IOException If an error occurs