    001// Copyright 2010 The Apache Software Foundation
    002//
    003// Licensed under the Apache License, Version 2.0 (the "License");
    004// you may not use this file except in compliance with the License.
    005// You may obtain a copy of the License at
    006//
    007// http://www.apache.org/licenses/LICENSE-2.0
    008//
    009// Unless required by applicable law or agreed to in writing, software
    010// distributed under the License is distributed on an "AS IS" BASIS,
    011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012// See the License for the specific language governing permissions and
    013// limitations under the License.
    014
    015package org.apache.tapestry5;
    016
    017import java.io.IOException;
    018
    019import org.apache.tapestry5.annotations.Environmental;
    020import org.apache.tapestry5.services.ComponentEventResultProcessor;
    021import org.apache.tapestry5.services.Traditional;
    022
    023/**
    024 * Extends {@link ComponentEventCallback} with a way to determine if the underlying event has been aborted
    025 * due to a some event returning an acceptable, non-null value. The standard implementation of this
    026 * is a wrapper around either the {@linkplain Traditional traditional} or
    027 * {@linkplain org.apache.tapestry5.services.Ajax ajax} versions of the {@link ComponentEventResultProcessor}
    028 * service, i.e., they allow for a navigational result.
    029 * <p>
    030 * Instances of this are made available via the {@link Environmental} annotation.
    031 *
    032 * @since 5.2.0
    033 */
    034public interface TrackableComponentEventCallback<T> extends ComponentEventCallback<T>
    035{
    036    /**
    037     * Returns true if a return value from an event handler method was processed.
    038     */
    039    boolean isAborted();
    040
    041    /**
    042     * If processing a return value threw an IOException, invoking this method will rethrow it.
    043     */
    044    void rethrow() throws IOException;
    045}