mirror of git://gcc.gnu.org/git/gcc.git
136 lines
4.0 KiB
Java
136 lines
4.0 KiB
Java
/* BasicMapEntry.java -- a class providing a plain-vanilla implementation of
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the Map.Entry interface; could be used anywhere in java.util
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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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* a class which implements Map.Entry
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*
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* @author Jon Zeppieri
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* @version $Revision: 1.3 $
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* @modified $Id: BasicMapEntry.java,v 1.3 2000/03/15 21:59:07 rao Exp $
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*/
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class BasicMapEntry implements Map.Entry
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{
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/** the key */
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Object key;
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/** the value */
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Object value;
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/**
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* construct a new BasicMapEntry with the given key and value
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*
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* @param newKey the key of this Entry
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* @param newValue the value of this Entry
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*/
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BasicMapEntry(Object newKey, Object newValue)
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{
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key = newKey;
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value = newValue;
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}
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/**
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* returns true if <pre>o</pre> is a Map.Entry and
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* <pre>
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* (((o.getKey == null) ? (key == null) :
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* o.getKey().equals(key)) &&
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* ((o.getValue() == null) ? (value == null) :
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* o.getValue().equals(value)))
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* </pre>
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*
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* NOTE: the calls to getKey() and getValue() in this implementation
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* are <i>NOT</i> superfluous and should not be removed. They insure
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* that subclasses such as HashMapEntry work correctly
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*
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* @param o the Object being tested for equality
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*/
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public boolean equals(Object o)
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{
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Map.Entry tester;
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Object oTestingKey, oTestingValue;
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Object oKey, oValue;
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if (o instanceof Map.Entry)
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{
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tester = (Map.Entry) o;
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oKey = getKey();
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oValue = getValue();
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oTestingKey = tester.getKey();
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oTestingValue = tester.getValue();
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return (((oTestingKey == null) ? (oKey == null) :
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oTestingKey.equals(oKey)) &&
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((oTestingValue == null) ? (oValue == null) :
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oTestingValue.equals(oValue)));
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}
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return false;
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}
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/** returns the key */
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public Object getKey()
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{
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return key;
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}
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/** returns the value */
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public Object getValue()
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{
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return value;
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}
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/** the hashCode() for a Map.Entry is
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* <pre>
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* ((getKey() == null) ? 0 : getKey().hashCode()) ^
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* ((getValue() == null) ? 0 : getValue().hashCode());
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* </pre>
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*
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* NOTE: the calls to getKey() and getValue() in this implementation
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* are <i>NOT</i> superfluous and should not be removed. They insure
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* that subclasses such as HashMapEntry work correctly
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*/
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public int hashCode()
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{
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Object oKey = getKey();
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Object oValue = getValue();
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return ((oKey == null) ? 0 : oKey.hashCode()) ^
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((oValue == null) ? 0 : oValue.hashCode());
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}
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/**
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* sets the value of this Map.Entry
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*
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* @param newValue the new value of this Map.Entry
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*/
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public Object setValue(Object newValue)
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throws java.lang.UnsupportedOperationException, ClassCastException,
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IllegalArgumentException, NullPointerException
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{
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Object oVal = value;
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value = newValue;
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return oVal;
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}
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}
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