org.jboss.elemento.Attachable Maven / Gradle / Ivy
/*
* Copyright 2023 Red Hat
*
* 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
*
* https://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.jboss.elemento;
import elemental2.dom.HTMLElement;
import elemental2.dom.MutationRecord;
import static org.jboss.elemento.BodyObserver.addAttachObserver;
import static org.jboss.elemento.BodyObserver.addDetachObserver;
import static org.jboss.elemento.BodyObserver.removeAttachObserver;
import static org.jboss.elemento.BodyObserver.removeDetachObserver;
/**
* Interface to get notified when an element has been attached / detached from the DOM.
*
* Important:
* The {@link #attach(MutationRecord)} / {@link #detach(MutationRecord)} methods are only called once after the
* attachable implementation has been registered with {@link #register(HTMLElement, Attachable)}. If you hold a reference to the
* element, and the element is attached to the DOM again, the callbacks are not called again, unless the element has been
* registered again. This is done for reasons of optimisation and performance.
*
* {@snippet class = Greeting region = attach}
*/
public interface Attachable {
/** Registers the specified element for both attach and detach. */
static void register(HTMLElement element, Attachable attachable) {
if (element != null) {
addAttachObserver(element, attachable::attach);
addDetachObserver(element, attachable::detach);
}
}
/**
* Unregisters the specified element for both attach and detach.
*/
static void unregister(HTMLElement element) {
if (element != null) {
removeAttachObserver(element);
removeDetachObserver(element);
}
}
/** Registers the specified element for both attach and detach. */
static void register(IsElement element, Attachable attachable) {
if (element != null) {
register(element.element(), attachable);
}
}
/** Called if the element has been attached. */
void attach(MutationRecord mutationRecord);
/** Called if the element has been detached. Default implementation does nothing. */
default void detach(MutationRecord mutationRecord) {
// noop
}
}