lava.io
Class FilteredInputStream

java.lang.Object
  |
  +--java.io.InputStream
        |
        +--java.io.FilterInputStream
              |
              +--lava.io.FilteredInputStream

public abstract class FilteredInputStream

extends java.io.FilterInputStream

Removes characters from base input stream.

Details: FilteredInputStream is a FilterInputStream that accepts or rejects characters from the base input stream according to a specified criteria, on a per-character basis, passing on only accepted characters. The acceptance criteria is determined by the implementation of the accept method.

Example: The following program reads ASCII characters from System.in and outputs only the visible characters to System.out. Note how the accept method is overridden directly in the constructor call.

import java.io.IOException; import lava.clib.Ctype; import lava.io.FilteredInputStream; class isgraph { public static void main (String[] args) throws IOException { FilteredInputStream in = new FilteredInputStream (System.in) { protected boolean accept (int c) { return Ctype.isgraph (c); } }; while (true) { int c = in . read (); if (c < 0) break; System.out . print ((char) c); } in . close (); } }

Since:

1999.04.14

Version:

1999.04.14

Author:

Sharky

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

FilteredInputStream(java.io.InputStream in)
Specifies base input stream.

Method Summary

protected abstract boolean	accept(int c) Defines acceptable characters.
int	read() Returns a filtered character.

Methods inherited from class java.io.FilterInputStream

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

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FilteredInputStream

public FilteredInputStream(java.io.InputStream in)

Specifies base input stream.

Details: This constructor establishes in as the base input stream to be filtered.

Parameters:

in - the base input stream

Method Detail

read

public int read()
         throws java.io.IOException

Returns a filtered character.

Details: read consumes a character from the base input stream, testing its acceptability by passing it to the accept method, and then returning the character if it has been accepted. If the character is not accepted, read drops the character and tries the next character. This continues until an acceptable character is found or the EOS is reached. If the EOS is reached, read returns -1.

Overrides:

read in class java.io.FilterInputStream

Returns:

an acceptable character

Throws:

java.io.IOException - if an I/O error occurs

accept

protected abstract boolean accept(int c)

Defines acceptable characters.

Details: accept defines the behavior of this FilteredInputStream by determining whether characters should be accepted or rejected. accept returns true if the supplied character is acceptable, false otherwise.

Parameters:

c - the character

Returns:

true iff the character should be accepted