/***
* Excerpted from "Code in the Cloud",
* published by The Pragmatic Bookshelf.
* Copyrights apply to this code. It may not be used to create training material,
* courses, books, articles, and the like. Contact us if you are in doubt.
* We make no guarantees that this code is fit for any purpose.
* Visit http://www.pragmaticprogrammer.com/titles/mcappe for more book information.
***/
// Copyright 2010, Mark C. Chu-Carroll (markcc@gmail.com).
// 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.pragprog.aebook.persistchat.client;
import java.util.Date;
import java.util.List;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.event.dom.client.KeyUpEvent;
import com.google.gwt.event.dom.client.KeyUpHandler;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.DialogBox;
import com.google.gwt.user.client.ui.HTML;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.TextArea;
import com.google.gwt.user.client.ui.TextBox;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.pragprog.aebook.persistchat.ChatMessage;
/**
* Entry point classes define <code>onModuleLoad()</code>.
*/
public class PersistChat implements EntryPoint {
/**
* The message displayed to the user when the server cannot be reached or
* returns an error.
*/
private static final String SERVER_ERROR = "An error occurred while "
+ "attempting to contact the server. Please check your network "
+ "connection and try again.";
/**
* Create a remote service proxy to talk to the server-side Greeting
* service.
*/
private final ChatSubmissionServiceAsync chatService = GWT
.create(ChatSubmissionService.class);
private String chat;
/**
* Sets up a call and callback to retrieve the list of available chats. When
* the server responds, this will create the link widgets, and add them to
* the chatListPanel.
*
* @param chatListPanel
*/
public void populateChats(final VerticalPanel chatListPanel) {
chatService.getChats(new AsyncCallback<List<String>>() {// (1)
public void onFailure(Throwable caught) {// (2)
chatListPanel.add(new Label("Couldn't retrieve chats"));
}
public void onSuccess(List<String> chats) {// (3)
for (String chat : chats) {
Button chatButton = new Button(chat); // (4)
chatListPanel.add(chatButton);
PersistChat.this.setupChatClickHandler(chatButton,
chat);// (5)
}
}
});
}
protected void setupChatClickHandler(Button chatButton, String chat) {
// TODO Auto-generated method stub
}
/**
* This is the entry point method.
*/
public void onModuleLoad() {
final VerticalPanel mainVert = new VerticalPanel(); // (6)
final VerticalPanel topPanel = new VerticalPanel(); // (7)
final HorizontalPanel midPanel = new HorizontalPanel();
final VerticalPanel bottomPanel = new VerticalPanel();
mainVert.add(topPanel); // (8)
mainVert.add(midPanel);
mainVert.add(bottomPanel);
final Label title = new Label("AppEngine Chat"); // (9)
final Label subtitle = new Label(new Date().toString());
title.addStyleName("title"); // (10)
mainVert.add(title);// (11)
mainVert.add(subtitle);
final VerticalPanel chatList = new VerticalPanel(); // (12)
final Label chatLabel = new Label("CHATS");
chatList.add(chatLabel);
chatList.setWidth("20em");
populateChats(chatList);
final TextArea text = new TextArea();
text.setWidth("60em");
midPanel.add(chatList);
midPanel.add(text);
final TextBox messageBox = new TextBox(); // (13)
final Button sendButton = new Button("send");
bottomPanel.add(messageBox);
bottomPanel.add(sendButton);
setupSendMessageHandlers(sendButton, messageBox); // (14)
RootPanel.get().add(mainVert); // (15)
// focus the cursor on the message box.
messageBox.setFocus(true); // (16)
messageBox.selectAll();
// Create a new timer
Timer elapsedTimer = new Timer() {
long timestamp = System.currentTimeMillis();
public void run() {
long new_timestamp = System.currentTimeMillis();
chatService.getMessagesSince(timestamp,
new AsyncCallback<List<ChatMessage>>() {
public void onFailure(Throwable caught) {
// If a periodic update fails, don't worry about
// it.
}
public void onSuccess(List<ChatMessage> newMessages) {
addNewMessages(newMessages);
}
});
timestamp = new_timestamp;
}
};
// Schedule the timer for every 1/2 second (500 milliseconds)
elapsedTimer.scheduleRepeating(500);
}
private void setupSendMessageHandlers(final Button sendButton,
final TextBox messageBox) {
// Create a handler for the sendButton and nameField
class SendMessageHandler implements ClickHandler,// (17)
KeyUpHandler {
/** Fired when the user clicks on the sendButton. */
public void onClick(ClickEvent event) {// (18)
sendMessageToServer();
}
/** Fired when the user types in the nameField. */
public void onKeyUp(KeyUpEvent event) {// (19)
if (event.getNativeKeyCode() == KeyCodes.KEY_ENTER) {
sendMessageToServer();
}
}
/** Send a chat message to the server. */
private void sendMessageToServer() { // (20)
ChatMessage chatmsg = new ChatMessage(getUser(), messageBox
.getText(), getCurrentChat());
messageBox.setText("");
chatService.postMessage(chatmsg,
new AsyncCallback<List<ChatMessage>>() {
public void onFailure(Throwable caught) {
PersistChat.this.addNewMessage(new ChatMessage(
"System", "Error sending message: "
+ caught.getMessage(),
getCurrentChat()));
}
public void onSuccess(List<ChatMessage> newMessages) {
PersistChat.this.addNewMessages(newMessages);
}
});
}
}
SendMessageHandler handler = new SendMessageHandler();// (21)
sendButton.addClickHandler(handler);
messageBox.addKeyUpHandler(handler);
}
public String getUser() {
// TODO Auto-generated method stub
return null;
}
protected String getCurrentChat() {
return chat;
}
protected void addNewMessages(List<ChatMessage> newMessages) {
// TODO Auto-generated method stub
}
protected void addNewMessage(ChatMessage newMessage) {
}
}