/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.wicket.model;
import org.apache.wicket.Component;
import org.apache.wicket.util.io.IClusterable;
/**
* Implementations of this interface compare model object. The component is given so that a
* developer can choose what the previous object is The default implementation for form components
* is just component.getModelObject(); But developers can choose to keep the last rendered value for
* that component and compare this value with the newObject. So that it doesn't overwrite values for
* an object that was changed by another session if the current session didn't touch that specific
* value.
*
* @author jcompagner
* @author Jonathan Locke
*
*/
@FunctionalInterface
public interface IModelComparator extends IClusterable
{
/**
* A model comparator that always returns false
*/
IModelComparator ALWAYS_FALSE = (IModelComparator) (component, newObject) -> false;
/**
* @param component
* The component which received the new object
* @param newObject
* The newObject
* @return True if the previous components object is the same as the newObject.
*/
boolean compare(Component component, Object newObject);
}