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