/*
 * Copyright 2016 Square Inc.
 *
 * 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 flowless;

/**
 * Supplied by Flow to the Listener, which is responsible for calling onComplete().
 */
public interface TraversalCallback {
    /**
     * Must be called exactly once to indicate that the corresponding transition has completed.
     *
     * If not called, the history will not be updated and further calls to Flow will not execute.
     * Calling more than once will result in an exception.
     */
    void onTraversalCompleted();
}
