001/* RandomAccess.java -- A tagging interface that lists can use to tailor 002 operations to the correct algorithm 003 Copyright (C) 2001, 2005 Free Software Foundation, Inc. 004 005This file is part of GNU Classpath. 006 007GNU Classpath is free software; you can redistribute it and/or modify 008it under the terms of the GNU General Public License as published by 009the Free Software Foundation; either version 2, or (at your option) 010any later version. 011 012GNU Classpath is distributed in the hope that it will be useful, but 013WITHOUT ANY WARRANTY; without even the implied warranty of 014MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 015General Public License for more details. 016 017You should have received a copy of the GNU General Public License 018along with GNU Classpath; see the file COPYING. If not, write to the 019Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02002110-1301 USA. 021 022Linking this library statically or dynamically with other modules is 023making a combined work based on this library. Thus, the terms and 024conditions of the GNU General Public License cover the whole 025combination. 026 027As a special exception, the copyright holders of this library give you 028permission to link this library with independent modules to produce an 029executable, regardless of the license terms of these independent 030modules, and to copy and distribute the resulting executable under 031terms of your choice, provided that you also meet, for each linked 032independent module, the terms and conditions of the license of that 033module. An independent module is a module which is not derived from 034or based on this library. If you modify this library, you may extend 035this exception to your version of the library, but you are not 036obligated to do so. If you do not wish to do so, delete this 037exception statement from your version. */ 038 039 040package java.util; 041 042/** 043 * Marker interface used to inform <code>List</code> implementations that 044 * they support fast (usually constant time) random access. This allows 045 * generic list algorithms to tailor their behavior based on the list 046 * type. 047 * <p> 048 * 049 * For example, some sorts are n*log(n) on an array, but decay to quadratic 050 * time on a linked list. As a rule of thumb, this interface should be 051 * used is this loop:<br> 052 * <code>for (int i = 0, n = list.size(); i < n; i++) list.get(i);</code> 053 * <br>runs faster than this loop:<br> 054 * <code>for (Iterator i = list.iterator(); i.hasNext(); ) i.next();</code> 055 * 056 * @author Eric Blake (ebb9@email.byu.edu) 057 * @see List 058 * @since 1.4 059 * @status updated to 1.4 060 */ 061public interface RandomAccess 062{ 063 // Tagging interface only. 064}