CanvasListener.java

/*
 * Copyright 2016 Red Hat, Inc. and/or its affiliates.
 *
 * 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 org.kie.workbench.common.stunner.core.client.canvas.listener;

/**
 * A canvas shape/element registration listener.
 */
public interface CanvasListener<C, E> {

    /**
     * An item is registered on the canvas.
     */
    void register(final E item);

    /**
     * An item is de-registered from the canvas.
     */
    void deregister(final E item);

    /**
     * All items removed from canvas.
     */
    void clear();
}