/*
* Copyright 2011 Google Inc.
*
* 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 com.google.gwt.sample.mobilewebapp.presenter.tasklist;
import com.google.gwt.sample.mobilewebapp.client.ClientFactory;
import com.google.gwt.sample.mobilewebapp.client.event.ShowTaskEvent;
import com.google.gwt.sample.mobilewebapp.client.event.TaskListUpdateEvent;
import com.google.gwt.sample.mobilewebapp.shared.TaskProxy;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.ui.Widget;
import com.google.web.bindery.event.shared.EventBus;
import com.google.web.bindery.requestfactory.shared.Receiver;
import com.google.web.bindery.requestfactory.shared.ServerFailure;
import java.util.Collections;
import java.util.List;
/**
* Activity that presents a list of tasks.
*/
public class TaskListPresenter implements TaskListView.Presenter {
/**
* The delay in milliseconds between calls to refresh the task list.
*/
private static final int REFRESH_DELAY = 5000;
/**
* A boolean indicating that we should clear the task list when started.
*/
private final boolean clearTaskList;
private final ClientFactory clientFactory;
private EventBus eventBus;
/**
* The refresh timer used to periodically refresh the task list.
*/
private Timer refreshTimer;
public TaskListPresenter(ClientFactory clientFactory, boolean clearTaskList) {
this.clientFactory = clientFactory;
this.clearTaskList = clearTaskList;
clientFactory.getTaskListView().setPresenter(this);
}
/**
* Construct a new {@link TaskListPresenter}.
*
* @param clientFactory the {@link ClientFactory} of shared resources
* @param place configuration for this activity
*/
public TaskListPresenter(ClientFactory clientFactory, TaskListPlace place) {
this(clientFactory, place.isTaskListStale());
}
@Override
public Widget asWidget() {
return getView().asWidget();
}
@Override
public String mayStop() {
return null; // always happy to stop
}
public void selectTask(TaskProxy selected) {
// Go into edit mode when a task is selected.
eventBus.fireEvent(new ShowTaskEvent(selected));
}
@Override
public void start(EventBus eventBus) {
this.eventBus = eventBus;
// Add a handler to the 'add' button in the shell.
clientFactory.getShell().setAddButtonVisible(true);
// Clear the task list and display it.
if (clearTaskList) {
getView().clearList();
}
// Create a timer to periodically refresh the task list.
refreshTimer = new Timer() {
@Override
public void run() {
refreshTaskList();
}
};
// Load the saved task list from storage
List<TaskProxy> list = clientFactory.getTaskProxyLocalStorage().getTasks();
setTasks(list);
// Request the task list now.
refreshTaskList();
}
@Override
public void stop() {
eventBus = null;
// Kill the refresh timer.
if (refreshTimer != null) {
refreshTimer.cancel();
}
}
private TaskListView getView() {
return clientFactory.getTaskListView();
}
/**
* Refresh the task list.
*/
private void refreshTaskList() {
clientFactory.getRequestFactory().taskRequest().findAllTasks().fire(
new Receiver<List<TaskProxy>>() {
@Override
public void onFailure(ServerFailure error) {
// ignore
}
@Override
public void onSuccess(List<TaskProxy> response) {
// Early exit if this activity has already been canceled.
if (eventBus == null) {
return;
}
// Display the tasks in the view.
if (response == null) {
response = Collections.<TaskProxy> emptyList();
}
setTasks(response);
// save the response to storage
clientFactory.getTaskProxyLocalStorage().setTasks(response);
// Restart the timer.
refreshTimer.schedule(REFRESH_DELAY);
}
});
}
/**
* Set the list of tasks.
*/
private void setTasks(List<TaskProxy> tasks) {
getView().setTasks(tasks);
eventBus.fireEventFromSource(new TaskListUpdateEvent(tasks), this);
}
}