/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.waveprotocol.box.webclient.client;
import com.google.gwt.event.logical.shared.ValueChangeHandler;
/**
* The Interface HistoryProvider gives access to the browser history stack in
* order to access to the wave tokens.
*
* Also this give us the opportunity to intercept these wave token petitions.
* Imagine that you are in fact using #clean-urls in your client you can return
* the waveref equivalent to the #clean-url when the wave webclient ask for the
* current token.
*
* @author vjrj@ourproject.org
*/
public interface HistoryProvider {
/**
* Gets the current wave history token. The handler will not receive a
* {@link ValueChangeHandler#onValueChange(com.google.gwt.event.logical.shared.ValueChangeEvent)}
* event for the initial token; requiring that an application request the
* token explicitly on startup gives it an opportunity to run different
* initialization code in the presence or absence of an initial token.
*
* @return the initial token, or the empty string if none is present.
*/
String getToken();
}