NavigationEvent.java

/*
 * Copyright 2012 Cedric Hauber
 *
 *    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.jboss.errai.mvp.client.events;

import com.google.gwt.event.shared.GwtEvent;
import com.google.gwt.event.shared.HasHandlers;
import org.jboss.errai.mvp.client.places.PlaceRequest;

/**
 * Event fired after navigation has occurred. It will not be fired if navigation is
 * refused through {@link PlaceManager#setOnLeaveConfirmation}, instead
 * {@link NavigationRefusedEvent} will.
 * <p />
 * Instead of registering your presenter towards this event, consider overriding
 * {@link com.gwtplatform.mvp.client.PresenterWidget#onReset()}. From there
 * you can call {@link PlaceManager#getCurrentPlaceRequest()} to get the
 * {@link PlaceRequest}.
 *
 * @see NavigationRefusedEvent
 *
 * @author Philippe Beaudoin
 */
public final class NavigationEvent extends GwtEvent<NavigationHandler> {
  private static final Type<NavigationHandler> TYPE = new Type<NavigationHandler>();

  /**
   * Fires a {@link org.jboss.errai.mvp.client.events.NavigationEvent}
   * into a source that has access to an {@link com.google.web.bindery.event.shared.EventBus}.
   *
   * @param source The source that fires this event ({@link com.google.gwt.event.shared.HasHandlers}).
   * @param request The {@link PlaceRequest} that was navigated to.
   */
  public static void fire(final HasHandlers source, PlaceRequest request) {
    source.fireEvent(new NavigationEvent(request));
  }

  public static Type<NavigationHandler> getType() {
    return TYPE;
  }

  private final PlaceRequest request;

  /**
   * Create a navigation event and attach it to a place request. You can pass
   * {@code null} as a request if it's unknown, for example when revealing a
   * default place or an error place.
   *
   * @param request The {@link PlaceRequest}.
   */
  public NavigationEvent(PlaceRequest request) {
    this.request = request;
  }

  @Override
  public Type<NavigationHandler> getAssociatedType() {
    return getType();
  }

  /**
   * Access the {@link PlaceRequest} that triggered that navigation event.
   *
   * @return The {@link PlaceRequest} or {@code null} if no place request is
   *         known.
   */
  public PlaceRequest getRequest() {
    return request;
  }

  @Override
  protected void dispatch(NavigationHandler handler) {
    handler.onNavigation(this);
  }
}