/**
*    Copyright 2011,2012, Big Switch Networks, Inc. 
*    Originally created by David Erickson, Stanford University
* 
*    Licensed under the Apache License, Version 2.0 (the "License"); you may
*    not use this file except in compliance with the License. You may obtain
*    a copy of the License at
*
*         http://www.apache.org/licenses/LICENSE-2.0
*
*    Unless required by applicable law or agreed to in writing, software
*    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
*    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
*    License for the specific language governing permissions and limitations
*    under the License.
**/

package net.floodlightcontroller.devicemanager;

import java.util.EnumSet;

import net.floodlightcontroller.devicemanager.IDeviceService.DeviceField;
import net.floodlightcontroller.devicemanager.internal.Device;

/**
 * Entities within an entity class are grouped into {@link Device} objects
 * based on the {@link IEntityClass}, and the key fields specified by the entity 
 * class. A set of entities are considered to be the same device if and only 
 * if they belong to the same entity class and they match on all key fields 
 * for that entity class. A field is effectively wildcarded by not including 
 * it in the list of key fields returned by {@link IEntityClassifierService} and/or 
 * {@link IEntityClass}.
 * 
 * Note that if you're not using static objects, you'll need to override
 * {@link Object#equals(Object)} and {@link Object#hashCode()}.
 * 
 * @author readams
 *
 */
public interface IEntityClass {
    /**
     * Return the set of key fields for this entity class.  Entities 
     * belonging to this class that differ in fields not included in 
     * this collection will be considered the same device.  The key 
     * fields for an entity class must not change unless associated 
     * with a flush of that entity class.
     * 
     * @return a set containing the fields that should not
     * be wildcarded.  May be null to indicate that all fields are key fields.
     */
    EnumSet<DeviceField> getKeyFields();
    
    /**
     * Returns a user-friendly, unique name for this EntityClass
     * @return the name of the entity class
     */
    String getName();
}