/*
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.control;

import net.wotonomy.foundation.NSMutableDictionary;
import net.wotonomy.foundation.NSNull;

/**
 * EOGenericRecord extends EOCustomObject to provide a general-purpose
 * implementation, relying entirely on the class description for entity-specific
 * behavior, and storing data in a dictionary.
 *
 * @author michael@mpowers.net
 * @author $Author: cgruber $
 * @version $Revision: 894 $
 */
public class EOGenericRecord extends EOCustomObject {
	private EOClassDescription classDescription;
	private NSMutableDictionary dataDictionary;

	/**
	 * Default constructor.
	 */
	protected EOGenericRecord() {
		classDescription = null;
		dataDictionary = new NSMutableDictionary();
	}

	/**
	 * Preferred constructor.
	 */
	public EOGenericRecord(EOClassDescription aDescription) {
		this();
		classDescription = aDescription;
	}

	/**
	 * Overridden to return true so that deferred faults are used.
	 */
	public static boolean usesDeferredFaultCreation() {
		return true;
	}

	/**
	 * Compatibility constructor: aContext and anID are ignored.
	 */
	public EOGenericRecord(EOEditingContext aContext, EOClassDescription aDescription, EOGlobalID anID) {
		this(aDescription);
	}

	/**
	 * Returns a class description for this object. Overridden to return the class
	 * description passed into the constructor.
	 */
	public EOClassDescription classDescription() {
		return classDescription;
	}

	// interface EOKeyValueCoding

	/**
	 * Calls storedValueForKey.
	 */
	public Object valueForKey(String aKey) {
		return storedValueForKey(aKey);
	}

	/**
	 * Calls willChange and then calls takeStoredValueForKey.
	 */
	public void takeValueForKey(Object aValue, String aKey) {
		willChange();
		takeStoredValueForKey(aValue, aKey);
	}

	/**
	 * Calls willRead for the specified key, and returns the corresponding value
	 * from the data dictionary. Keys that do not exist will return null.
	 */
	public Object storedValueForKey(String aKey) {
		willRead(aKey);
		Object result = dataDictionary.objectForKey(aKey);
		if (NSNull.nullValue().equals(result))
			result = null;
		return result;
	}

	/**
	 * Writes the specified value into the data dictionary for the specified key.
	 * Nulls are stored as NSNulls in the dictionary. No checking is performed to
	 * determine whether the key is a valid attribute key.
	 */
	public void takeStoredValueForKey(Object aValue, String aKey) {
		if (aValue == null)
			aValue = NSNull.nullValue();
		dataDictionary.setObjectForKey(aValue, aKey);
	}

}

/*
 * $Log$ Revision 1.2 2006/02/16 16:47:14 cgruber Move some classes in to
 * "internal" packages and re-work imports, etc.
 *
 * Also use UnsupportedOperationExceptions where appropriate, instead of
 * WotonomyExceptions.
 *
 * Revision 1.1 2006/02/16 13:19:57 cgruber Check in all sources in
 * eclipse-friendly maven-enabled packages.
 *
 * Revision 1.2 2003/08/06 23:07:52 chochos general code cleanup (mostly,
 * removing unused imports)
 *
 * Revision 1.1 2001/11/18 18:57:10 mpowers Implemented EOGenericRecord.
 *
 *
 */