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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libjava/classpath/gnu/java/io/ObjectIdentityWrapper.java | |
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Diffstat (limited to 'libjava/classpath/gnu/java/io/ObjectIdentityWrapper.java')
-rw-r--r-- | libjava/classpath/gnu/java/io/ObjectIdentityWrapper.java | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/java/io/ObjectIdentityWrapper.java b/libjava/classpath/gnu/java/io/ObjectIdentityWrapper.java new file mode 100644 index 000000000..53c9943de --- /dev/null +++ b/libjava/classpath/gnu/java/io/ObjectIdentityWrapper.java @@ -0,0 +1,100 @@ +/* ObjectIdentityWrapper.java -- Wrapper class used to override equals() + and hashCode() to be as discriminating as possible + Copyright (C) 1998 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package gnu.java.io; + +/** + This class is a thin wrapper around <code>Object</code> that makes + the methods <code>hashCode()</code> and <code>equals(Object)</code> + as discriminating as possible. +*/ +public class ObjectIdentityWrapper +{ + + /** + Constructs a <code>ObjectIdentityWrapper</code> that is wrapped + around o. + */ + public ObjectIdentityWrapper( Object o ) + { + object = o; + } + + /** + Uses <code>System.identityHashCode(Object)</code> to compute a + hash code for the object wrapped by this + <code>ObjectIdentityWrapper</code>. + + @see java.lang.System#identityHashCode(java.lang.Object) + @see java.util.Hashtable + @see java.lang.Object#hashCode() + */ + public int hashCode() + { + return System.identityHashCode( object ); + } + + /** + Uses the <code>==</code> operator to test for equality between + the object wrapped by this <code>ObjectIdentityWrapper</code> and + the object wrapped by the <code>ObjectIdentityWrapper</code> o. + Returns false if o is not a <code>ObjectIdentityWrapper</code>. + + @see java.util.Hashtable + @see java.lang.Object#equals() + */ + public boolean equals( Object o ) + { + if( o instanceof ObjectIdentityWrapper ) + return object == ((ObjectIdentityWrapper)o).object; + else + return false; + } + + public String toString() + { + return "ObjectIdentityWrapper< " + object + ", " + hashCode() + " >"; + } + + /** + The <code>Object</code> wrapped by this + <code>ObjectIdentityWrapper</code>. + */ + public Object object; +} |