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90 lines
2.7 KiB
Java
90 lines
2.7 KiB
Java
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/* ObjectIdentityWrapper.java -- Wrapper class used to override equals()
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and hashCode() to be as discriminating as possible
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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 gnu.java.io;
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/**
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This class is a thin wrapper around <code>Object</code> that makes
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the methods <code>hashCode()</code> and <code>equals(Object)</code>
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as discriminating as possible.
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*/
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public class ObjectIdentityWrapper
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{
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/**
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Constructs a <code>ObjectIdentityWrapper</code> that is wrapped
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around o.
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*/
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public ObjectIdentityWrapper( Object o )
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{
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object = o;
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}
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/**
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Uses <code>System.identityHashCode(Object)</code> to compute a
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hash code for the object wrapped by this
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<code>ObjectIdentityWrapper</code>.
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@see java.lang.System#identityHashCode(java.lang.Object)
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@see java.util.Hashtable
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@see java.lang.Object#hashCode()
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*/
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public int hashCode()
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{
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return System.identityHashCode( object );
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}
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/**
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Uses the <code>==</code> operator to test for equality between
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the object wrapped by this <code>ObjectIdentityWrapper</code> and
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the object wrapped by the <code>ObjectIdentityWrapper</code> o.
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Returns false if o is not a <code>ObjectIdentityWrapper</code>.
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@see java.util.Hashtable
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@see java.lang.Object#equals()
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*/
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public boolean equals( Object o )
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{
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if( o instanceof ObjectIdentityWrapper )
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return object == ((ObjectIdentityWrapper)o).object;
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else
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return false;
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}
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public String toString()
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{
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return "ObjectIdentityWrapper< " + object + ", " + hashCode() + " >";
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}
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/**
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The <code>Object</code> wrapped by this
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<code>ObjectIdentityWrapper</code>.
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*/
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public Object object;
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}
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