    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
    015    package org.apache.tapestry5;
    016
    017    import java.io.IOException;
    018
    019    import org.apache.tapestry5.annotations.Environmental;
    020    import org.apache.tapestry5.services.ComponentEventResultProcessor;
    021    import 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     */
    034    public 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    }