69 lines
2.9 KiB
Java
69 lines
2.9 KiB
Java
/*
|
|
* Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
|
|
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
|
|
*
|
|
* This code is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 only, as
|
|
* published by the Free Software Foundation. Oracle designates this
|
|
* particular file as subject to the "Classpath" exception as provided
|
|
* by Oracle in the LICENSE file that accompanied this code.
|
|
*
|
|
* This code 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
|
|
* version 2 for more details (a copy is included in the LICENSE file that
|
|
* accompanied this code).
|
|
*
|
|
* You should have received a copy of the GNU General Public License version
|
|
* 2 along with this work; if not, write to the Free Software Foundation,
|
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*
|
|
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
|
|
* or visit www.oracle.com if you need additional information or have any
|
|
* questions.
|
|
*/
|
|
|
|
package java.util;
|
|
|
|
/**
|
|
* Marker interface used by {@code List} implementations to indicate that
|
|
* they support fast (generally constant time) random access. The primary
|
|
* purpose of this interface is to allow generic algorithms to alter their
|
|
* behavior to provide good performance when applied to either random or
|
|
* sequential access lists.
|
|
*
|
|
* <p>The best algorithms for manipulating random access lists (such as
|
|
* {@code ArrayList}) can produce quadratic behavior when applied to
|
|
* sequential access lists (such as {@code LinkedList}). Generic list
|
|
* algorithms are encouraged to check whether the given list is an
|
|
* {@code instanceof} this interface before applying an algorithm that would
|
|
* provide poor performance if it were applied to a sequential access list,
|
|
* and to alter their behavior if necessary to guarantee acceptable
|
|
* performance.
|
|
*
|
|
* <p>It is recognized that the distinction between random and sequential
|
|
* access is often fuzzy. For example, some {@code List} implementations
|
|
* provide asymptotically linear access times if they get huge, but constant
|
|
* access times in practice. Such a {@code List} implementation
|
|
* should generally implement this interface. As a rule of thumb, a
|
|
* {@code List} implementation should implement this interface if,
|
|
* for typical instances of the class, this loop:
|
|
* <pre>
|
|
* for (int i=0, n=list.size(); i < n; i++)
|
|
* list.get(i);
|
|
* </pre>
|
|
* runs faster than this loop:
|
|
* <pre>
|
|
* for (Iterator i=list.iterator(); i.hasNext(); )
|
|
* i.next();
|
|
* </pre>
|
|
*
|
|
* <p>This interface is a member of the
|
|
* <a href="{@docRoot}/java.base/java/util/package-summary.html#CollectionsFramework">
|
|
* Java Collections Framework</a>.
|
|
*
|
|
* @since 1.4
|
|
*/
|
|
public interface RandomAccess {
|
|
}
|