src.it.unimi.dsi.fastutil.io.MeasurableStream Maven / Gradle / Ivy
package it.unimi.dsi.fastutil.io;
/*
* fastutil: Fast & compact type-specific collections for Java
*
* Copyright (C) 2010-2011 Sebastiano Vigna
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
import java.io.IOException;
/** An stream that provides eager access to its length,
* and keeps track of the current position (e.g., the number of bytes read so far, or the current
* position of the file pointer).
*
* This class has two methods, both specified as optional. This apparently bizarre
* behaviour is necessary because of wrapper classes which use reflection
* to support those methods (see, e.g., {@link MeasurableInputStream}, {@link FastBufferedInputStream} and {@link FastBufferedOutputStream}).
*
* @since 6.0.0
*/
public interface MeasurableStream {
/** Returns the overall length of this stream (optional operation). In most cases, this will require the
* stream to perform some extra action, possibly changing the state of the input stream itself (typically, reading
* all the bytes up to the end, or flushing on output stream).
* Implementing classes should always document what state will the input stream be in
* after calling this method, and which kind of exception could be thrown.
*/
public long length() throws IOException;
/** Returns the current position in this stream (optional operation).
*
*
Usually, the position is just the number of bytes read or written
* since the stream was opened, but in the case of a
* {@link it.unimi.dsi.fastutil.io.RepositionableStream} it
* represent the current position.
*/
public long position() throws IOException;
}