136 lines
4.0 KiB
Java
136 lines
4.0 KiB
Java
/* BasicMapEntry.java -- a class providing a plain-vanilla implementation of
|
|
the Map.Entry interface; could be used anywhere in java.util
|
|
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., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA.
|
|
|
|
As a special exception, if you link this library with other files to
|
|
produce an executable, this library does not by itself cause the
|
|
resulting executable to be covered by the GNU General Public License.
|
|
This exception does not however invalidate any other reasons why the
|
|
executable file might be covered by the GNU General Public License. */
|
|
|
|
|
|
package java.util;
|
|
|
|
/**
|
|
* a class which implements Map.Entry
|
|
*
|
|
* @author Jon Zeppieri
|
|
* @version $Revision: 1.3 $
|
|
* @modified $Id: BasicMapEntry.java,v 1.3 2000/03/15 21:59:07 rao Exp $
|
|
*/
|
|
class BasicMapEntry implements Map.Entry
|
|
{
|
|
/** the key */
|
|
Object key;
|
|
/** the value */
|
|
Object value;
|
|
|
|
/**
|
|
* construct a new BasicMapEntry with the given key and value
|
|
*
|
|
* @param newKey the key of this Entry
|
|
* @param newValue the value of this Entry
|
|
*/
|
|
BasicMapEntry(Object newKey, Object newValue)
|
|
{
|
|
key = newKey;
|
|
value = newValue;
|
|
}
|
|
|
|
/**
|
|
* returns true if <pre>o</pre> is a Map.Entry and
|
|
* <pre>
|
|
* (((o.getKey == null) ? (key == null) :
|
|
* o.getKey().equals(key)) &&
|
|
* ((o.getValue() == null) ? (value == null) :
|
|
* o.getValue().equals(value)))
|
|
* </pre>
|
|
*
|
|
* NOTE: the calls to getKey() and getValue() in this implementation
|
|
* are <i>NOT</i> superfluous and should not be removed. They insure
|
|
* that subclasses such as HashMapEntry work correctly
|
|
*
|
|
* @param o the Object being tested for equality
|
|
*/
|
|
public boolean equals(Object o)
|
|
{
|
|
Map.Entry tester;
|
|
Object oTestingKey, oTestingValue;
|
|
Object oKey, oValue;
|
|
if (o instanceof Map.Entry)
|
|
{
|
|
tester = (Map.Entry) o;
|
|
oKey = getKey();
|
|
oValue = getValue();
|
|
oTestingKey = tester.getKey();
|
|
oTestingValue = tester.getValue();
|
|
return (((oTestingKey == null) ? (oKey == null) :
|
|
oTestingKey.equals(oKey)) &&
|
|
((oTestingValue == null) ? (oValue == null) :
|
|
oTestingValue.equals(oValue)));
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/** returns the key */
|
|
public Object getKey()
|
|
{
|
|
return key;
|
|
}
|
|
|
|
/** returns the value */
|
|
public Object getValue()
|
|
{
|
|
return value;
|
|
}
|
|
|
|
/** the hashCode() for a Map.Entry is
|
|
* <pre>
|
|
* ((getKey() == null) ? 0 : getKey().hashCode()) ^
|
|
* ((getValue() == null) ? 0 : getValue().hashCode());
|
|
* </pre>
|
|
*
|
|
* NOTE: the calls to getKey() and getValue() in this implementation
|
|
* are <i>NOT</i> superfluous and should not be removed. They insure
|
|
* that subclasses such as HashMapEntry work correctly
|
|
*/
|
|
public int hashCode()
|
|
{
|
|
Object oKey = getKey();
|
|
Object oValue = getValue();
|
|
return ((oKey == null) ? 0 : oKey.hashCode()) ^
|
|
((oValue == null) ? 0 : oValue.hashCode());
|
|
}
|
|
|
|
/**
|
|
* sets the value of this Map.Entry
|
|
*
|
|
* @param newValue the new value of this Map.Entry
|
|
*/
|
|
public Object setValue(Object newValue)
|
|
throws java.lang.UnsupportedOperationException, ClassCastException,
|
|
IllegalArgumentException, NullPointerException
|
|
{
|
|
Object oVal = value;
|
|
value = newValue;
|
|
return oVal;
|
|
}
|
|
}
|