Place.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.places;

/**
 * <b>Important:</b> For simplicity, places do not participate in dependency
 * injection and can be created with <code>new</code>.
 * <p />
 * A place represents a particular 'bookmark' or location inside the
 * application. A place is stateful - it may represent a location with it's
 * current settings, such as a particular ID value, or other unique indicators
 * that will allow a user to track back to that location later, either via a
 * browser bookmark, or by clicking the 'back' button.
 *
 * @author Philippe Beaudoin
 */
public interface Place {

  /**
   * Checks if the associated presenter can be revealed.
   * <p />
   * The default implementation of this method always return <code>true</code>,
   * but subclasses should override this and check to make sure the current user
   * has the privileges to see the place. Make sure the places you request in
   * {@link PlaceManager#revealDefaultPlace()} and
   * {@link PlaceManager#revealErrorPlace(String)} can reveal themselves,
   * otherwise your application could get into an infinite loop.
   *
   * @return <code>true</code> if the presenter can be revealed,
   *         <code>false</code> otherwise.
   */
  boolean canReveal();

  /**
   * Places are equal if their name token matches.
   *
   * @return <code>true</code> if the places name token matches,
   *         <code>false</code> otherwise.
   */
  @Override
  boolean equals(Object o);

  /**
   * The name token is the first part of the history token, before the
   * parameters. It is meant to be a unique identifier of a place. An exception
   * will be thrown if two places are registered with the same name token.
   *
   * @return The name token for this place.
   */
  String getNameToken();

  @Override
  int hashCode();

  /**
   * Makes sure the method matches the passed request.
   *
   * @param request The request to check.
   * @return <code>true</code> if the ID matches this place's name.
   */
  boolean matchesRequest(PlaceRequest request);

  @Override
  String toString();

}