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/*
Wotonomy: OpenStep design patterns for pure Java applications.
Copyright (C) 2001 Intersect Software Corporation
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, see http://www.gnu.org
*/
package net.wotonomy.foundation;
import net.wotonomy.foundation.internal.Introspector;
import net.wotonomy.foundation.internal.IntrospectorException;
import net.wotonomy.foundation.internal.MissingPropertyException;
import net.wotonomy.foundation.internal.NullPrimitiveException;
import net.wotonomy.foundation.internal.WotonomyException;
/**
* NSKeyValueCodingSupport defines default behavior for
* classes implementing NSKeyValueSupport. <br><br>
*
* On an object that does not implement NSKeyValueCoding,
* wotonomy will call the methods on this class directly.
*
* @author michael@mpowers.net
* @author $Author: cgruber $
* @version $Revision: 892 $
*/
public class NSKeyValueCodingSupport
{
/**
* Returns the value for the specified property key
* on the specified object. <br><br>
*
* If the property does not exist, this method calls
* handleQueryWithUnboundKey on the object if it
* implements NSKeyValueCoding, otherwise calls
* handleQueryWithUnboundKey on this class. <br><br>
*/
static public Object valueForKey(
Object anObject, String aKey )
{
//TODO: may need to handle "." nesting here so
// that handleQueryWithUnboundKey gets called for
// for the nested object, not the parent object
//Correction: need to handle key paths in
// KeyValueCodingAdditionsSupport.
try
{
return Introspector.get( anObject, aKey );
}
catch ( IntrospectorException exc )
{
if ( anObject instanceof NSKeyValueCoding )
{
return ((NSKeyValueCoding)anObject).handleQueryWithUnboundKey( aKey );
}
return handleQueryWithUnboundKey( anObject, aKey );
}
}
/**
* Sets the property to the specified value on
* the specified object.
*
* If the property does not exist, this method calls
* handleTakeValueForUnboundKey on the object if it
* implements NSKeyValueCoding, otherwise calls
* handleTakeValueForUnboundKey on this class.
*
* If the property is of a type that cannot allow
* null (e.g. primitive types) and aValue is null,
* this method should call unableToSetNullForKey
* on the object if it implements NSKeyValueCoding,
* otherwise calls unableToSetNullForKey on this class.
*/
static public void takeValueForKey(
Object anObject, Object aValue, String aKey )
{
//TODO: may need to handle "." nesting here so
// that handleTakeValueForUnboundKey gets called for
// for the nested object, not the parent object
try
{
Introspector.set( anObject, aKey, aValue );
}
catch ( NullPrimitiveException exc )
{
if ( anObject instanceof NSKeyValueCoding )
{
((NSKeyValueCoding)anObject).unableToSetNullForKey( aKey );
}
else
{
unableToSetNullForKey( anObject, aKey );
}
}
catch ( MissingPropertyException exc )
{
if ( anObject instanceof NSKeyValueCoding )
{
((NSKeyValueCoding)anObject).handleTakeValueForUnboundKey(
aValue, aKey );
}
else
{
handleTakeValueForUnboundKey( anObject, aValue, aKey );
}
}
}
/**
* Returns the value for the private field that
* corresponds to the specified property on
* the specified object.
*
* This implementation currently calls valueForKey,
* because java security currently prevents us from
* accessing the fields of another object.
*/
static public Object storedValueForKey(
Object anObject, String aKey )
{
//TODO: this currently just calls valueForKey
return valueForKey( anObject, aKey );
}
/**
* Sets the the private field that corresponds to the
* specified property to the specified value on the
* specified object.
*
* This implementation currently calls takeValueForKey,
* because java security currently prevents us from
* accessing the fields of another object.
*/
static public void takeStoredValueForKey(
Object anObject, Object aValue, String aKey )
{
//TODO: this currently just calls takeValueForKey
takeValueForKey( anObject, aValue, aKey );
}
/**
* Called by valueForKey when the specified key is
* not found on the specified object, if that object
* does not implement NSKeyValueCoding.
*
* This implementation throws a WotonomyException.
*/
static public Object handleQueryWithUnboundKey(
Object anObject, String aKey )
{
throw new WotonomyException(
"Key not found for object: "
+ aKey + " : " + anObject );
}
/**
* Called by takeValueForKey when the specified key
* is not found on the specified object, if that object
* does not implement NSKeyValueCoding.
*
* This implementation throws a WotonomyException.
*/
static public void handleTakeValueForUnboundKey(
Object anObject, Object aValue, String aKey )
{
throw new WotonomyException(
"Key not found for object while setting value: "
+ aKey + " : " + anObject + " : " + aValue );
}
/**
* Called by takeValueForKey when the type of the
* specified key is not allowed to be null, as is
* the case with primitive types, if the specified
* object does not implement NSKeyValueCoding.
*
* This implementation throws a WotonomyException.
*/
static public void unableToSetNullForKey(
Object anObject, String aKey )
{
throw new WotonomyException(
"Tried to key on object to null: "
+ aKey + " : " + anObject );
}
}
/*
* $Log$
* Revision 1.1 2006/02/16 12:47:16 cgruber
* Check in all sources in eclipse-friendly maven-enabled packages.
*
* Revision 1.1 2003/01/17 14:40:50 mpowers
* Adding files to fix build.
*
* Revision 1.4 2001/05/18 21:04:33 mpowers
* Reimplemented EditingContext.initializeObject.
*
* Revision 1.3 2001/04/27 00:28:29 mpowers
* Fixed a return value.
*
* Revision 1.2 2001/04/03 20:36:01 mpowers
* Fixed refaulting/reverting/invalidating to be self-consistent.
*
* Revision 1.1 2001/03/28 17:49:33 mpowers
* Implemented NSKeyValueCodingSupport.
*
*
*/
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