69 lines
2.9 KiB
Java
69 lines
2.9 KiB
Java
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/*
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* Copyright 2000-2006 Sun Microsystems, Inc. All Rights Reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Sun designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Sun in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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* CA 95054 USA or visit www.sun.com if you need additional information or
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* have any questions.
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*/
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package java.util;
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/**
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* Marker interface used by <tt>List</tt> implementations to indicate that
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* they support fast (generally constant time) random access. The primary
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* purpose of this interface is to allow generic algorithms to alter their
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* behavior to provide good performance when applied to either random or
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* sequential access lists.
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*
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* <p>The best algorithms for manipulating random access lists (such as
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* <tt>ArrayList</tt>) can produce quadratic behavior when applied to
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* sequential access lists (such as <tt>LinkedList</tt>). Generic list
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* algorithms are encouraged to check whether the given list is an
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* <tt>instanceof</tt> this interface before applying an algorithm that would
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* provide poor performance if it were applied to a sequential access list,
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* and to alter their behavior if necessary to guarantee acceptable
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* performance.
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*
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* <p>It is recognized that the distinction between random and sequential
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* access is often fuzzy. For example, some <tt>List</tt> implementations
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* provide asymptotically linear access times if they get huge, but constant
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* access times in practice. Such a <tt>List</tt> implementation
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* should generally implement this interface. As a rule of thumb, a
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* <tt>List</tt> implementation should implement this interface if,
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* for typical instances of the class, this loop:
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* <pre>
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* for (int i=0, n=list.size(); i < n; i++)
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* list.get(i);
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* </pre>
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* runs faster than this loop:
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* <pre>
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* for (Iterator i=list.iterator(); i.hasNext(); )
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* i.next();
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* </pre>
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*
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* <p>This interface is a member of the
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* <a href="{@docRoot}/../technotes/guides/collections/index.html">
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* Java Collections Framework</a>.
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*
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* @since 1.4
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*/
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public interface RandomAccess {
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}
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