/*
* 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.task;
import com.google.gwt.sample.mobilewebapp.client.ClientFactory;
import com.google.gwt.sample.mobilewebapp.client.event.ActionEvent;
import com.google.gwt.sample.mobilewebapp.client.event.ActionNames;
import com.google.gwt.sample.mobilewebapp.client.ui.SoundEffects;
import com.google.gwt.sample.mobilewebapp.shared.TaskProxy;
import com.google.gwt.sample.mobilewebapp.shared.TaskRequest;
import com.google.gwt.user.client.Window;
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.Request;
import com.google.web.bindery.requestfactory.shared.ServerFailure;
import java.util.Set;
import java.util.logging.Logger;
import javax.validation.ConstraintViolation;
/**
* Drives a {@link TaskEditView} to fetch and edit a given task, or to create a
* new one.
*/
public class TaskEditPresenter implements TaskEditView.Presenter {
private static final Logger log = Logger.getLogger(TaskEditPresenter.class.getName());
private final ClientFactory clientFactory;
/**
* Indicates whether the activity is editing an existing task or creating a
* new task.
*/
private boolean isEditing;
/**
* The current task being edited, provided by RequestFactory.
*/
private TaskProxy editTask;
/**
* The ID of the current task being edited.
*/
private final Long taskId;
/**
* The request used to persist the modified task.
*/
private Request<Void> taskPersistRequest;
private EventBus eventBus;
/**
* For creating a new task.
*/
public TaskEditPresenter(ClientFactory clientFactory) {
this.taskId = null;
this.clientFactory = clientFactory;
clientFactory.getTaskEditView().setPresenter(this);
}
/**
* For editing an existing task.
*/
public TaskEditPresenter(ClientFactory clientFactory, TaskProxy readOnlyTask) {
/*
* TODO surely we can find a way to show the read-only values while waiting
* for the async fetch
*/
this.taskId = readOnlyTask.getId();
this.clientFactory = clientFactory;
clientFactory.getTaskEditView().setPresenter(this);
}
@Override
public Widget asWidget() {
return getView().asWidget();
}
public void deleteTask() {
if (isEditing) {
doDeleteTask();
} else {
doCancelTask();
}
}
@Override
public String mayStop() {
if ((eventBus != null && editTask != null) && getView().getEditorDriver().isDirty()) {
return "Are you sure you want to discard these changes?";
}
return null;
}
public void saveTask() {
// Flush the changes into the editable task.
TaskRequest context = (TaskRequest) clientFactory.getTaskEditView().getEditorDriver().flush();
/*
* Create a persist request the first time we try to save this task. If a
* request already exists, reuse it.
*/
if (taskPersistRequest == null) {
taskPersistRequest = context.persist().using(editTask);
}
// Fire the request.
taskPersistRequest.fire(new Receiver<Void>() {
@Override
public void onConstraintViolation(Set<ConstraintViolation<?>> violations) {
handleConstraintViolations(violations);
}
@Override
public void onSuccess(Void response) {
editTask = null;
// Notify the user that the task was updated.
TaskEditPresenter.this.notify("Task Saved");
// Return to the task list.
ActionEvent.fire(eventBus, ActionNames.TASK_SAVED);
}
});
}
public void start(EventBus eventBus) {
this.eventBus = eventBus;
getView().setNameViolation(null);
// Prefetch the sounds used in this activity.
SoundEffects.get().prefetchError();
// Hide the 'add' button in the shell.
// TODO(rjrjr) Ick!
clientFactory.getShell().setAddButtonVisible(false);
if (taskId == null) {
startCreate();
} else {
startEdit();
}
}
@Override
public void stop() {
eventBus = null;
clientFactory.getTaskEditView().setLocked(false);
}
/**
* Cancel the current task.
*/
private void doCancelTask() {
ActionEvent.fire(eventBus, ActionNames.EDITING_CANCELED);
}
/**
* Delete the current task.
*/
private void doDeleteTask() {
if (editTask == null) {
return;
}
// Delete the task in the data store.
final TaskProxy toDelete = this.editTask;
clientFactory.getRequestFactory().taskRequest().remove().using(toDelete).fire(
new Receiver<Void>() {
@Override
public void onFailure(ServerFailure error) {
Window.alert("An error occurred on the server while deleting this task: \"."
+ error.getMessage() + "\".");
}
@Override
public void onSuccess(Void response) {
onTaskDeleted();
}
});
}
private TaskEditView getView() {
return clientFactory.getTaskEditView();
}
/**
* Handle constraint violations.
*/
private void handleConstraintViolations(Set<ConstraintViolation<?>> violations) {
// Display the violations.
getView().getEditorDriver().setConstraintViolations(violations);
// Play a sound.
SoundEffects.get().playError();
}
/**
* Notify the user of a message.
*
* @param message the message to display
*/
private void notify(String message) {
// TODO Add notification pop-up
log.fine("Tell the user: " + message);
}
/**
* Called when a task has been successfully deleted.
*/
private void onTaskDeleted() {
// Notify the user that the task was deleted.
notify("Task Deleted");
// Return to the task list.
ActionEvent.fire(eventBus, ActionNames.TASK_SAVED);
}
private void startCreate() {
isEditing = false;
getView().setEditing(false);
TaskRequest request = clientFactory.getRequestFactory().taskRequest();
editTask = request.create(TaskProxy.class);
getView().getEditorDriver().edit(editTask, request);
}
private void startEdit() {
isEditing = true;
getView().setEditing(true);
// Lock the display until the task is loaded.
getView().setLocked(true);
clientFactory.getRequestFactory().taskRequest().findTask(this.taskId).fire(
new Receiver<TaskProxy>() {
@Override
public void onConstraintViolation(Set<ConstraintViolation<?>> violations) {
getView().setLocked(false);
getView().getEditorDriver().setConstraintViolations(violations);
}
@Override
public void onFailure(ServerFailure error) {
getView().setLocked(false);
doCancelTask();
super.onFailure(error);
}
@Override
public void onSuccess(TaskProxy response) {
// Early exit if we have already stopped.
if (eventBus == null) {
return;
}
// Task not found.
if (response == null) {
Window.alert("The task with id '" + taskId + "' could not be found."
+ " Please select a different task from the task list.");
doCancelTask();
return;
}
// Show the task.
editTask = response;
getView().getEditorDriver().edit(response,
clientFactory.getRequestFactory().taskRequest());
getView().setLocked(false);
}
});
}
}