mirror of git://gcc.gnu.org/git/gcc.git
65 lines
2.8 KiB
Java
65 lines
2.8 KiB
Java
/* Comparator.java -- Interface for objects that specify an ordering
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Copyright (C) 1998 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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As a special exception, if you link this library with other files to
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produce an executable, this library does not by itself cause the
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resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why the
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executable file might be covered by the GNU General Public License. */
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package java.util;
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/**
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* Interface for objects that specify an ordering between objects. The ordering
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* can be <EM>total</EM>, such that two objects only compare equal if they are
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* equal by the equals method, or <EM>partial</EM> such that this is not
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* necessarily true. For example, a case-sensitive dictionary order comparison
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* of Strings is total, but if it is case-insensitive it is partial, because
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* "abc" and "ABC" compare as equal even though "abc".equals("ABC") returns
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* false.
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* <P>
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* In general, Comparators should be Serializable, because when they are passed
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* to Serializable data structures such as SortedMap or SortedSet, the entire
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* data structure will only serialize correctly if the comparator is
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* Serializable.
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*/
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public interface Comparator
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{
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/**
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* Return an integer that is negative, zero or positive depending on whether
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* the first argument is less than, equal to or greater than the second
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* according to this ordering. This method should obey the following contract:
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* <UL>
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* <LI>if compare(a, b) < 0 then compare(b, a) > 0</LI>
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* <LI>if compare(a, b) throws an exception, so does compare(b, a)</LI>
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* <LI>if compare(a, b) < 0 and compare(b, c) < 0 then compare(a, c)
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* < 0</LI>
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* <LI>if a.equals(b) or both a and b are null, then compare(a, b) == 0.
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* The converse need not be true, but if it is, this Comparator
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* specifies a <EM>total</EM> ordering.</LI>
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* </UL>
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*
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* @throws ClassCastException if the elements are not of types that can be
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* compared by this ordering.
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*/
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int compare(Object o1, Object o2);
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}
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