11.7. Google App Engine Integration

This section is not yet fully updated to Vaadin 7.

Vaadin includes support to run Vaadin applications in the Google App Engine (GAE). The most essential requirement for GAE is the ability to serialize the application state. Vaadin applications are serializable through the java.io.Serializable interface.

To run as a GAE application, an application must use GAEVaadinServlet instead of VaadinServlet, and of course implement the java.io.Serializable interface for all persistent classes. You also need to enable session support in appengine-web.xml with:

<sessions-enabled>true</sessions-enabled>

The Vaadin Project wizard can create the configuration files needed for GAE deployment. See Section 2.5.1, “Creating the Project”. When the Google App Engine deployment configuration is selected, the wizard will create the project structure following the GAE Servlet convention instead of the regular Servlet convention. The main differences are:

  • Source directory: src/main/java
  • Output directory: war/WEB-INF/classes
  • Content directory: war

Rules and Limitations

Running Vaadin applications in Google App Engine has the following rules and limitations:

  • Avoid using the session for storage, usual App Engine limitations apply (no synchronization, that is, it is unreliable).

  • Vaadin uses memcache for mutex, the key is of the form _vmutex<sessionid>.

  • The Vaadin WebApplicationContext class is serialized separately into memcache and datastore; the memcache key is _vac<sessionid> and the datastore entity kind is _vac with identifiers of the type _vac<sessionid>.

  • Do not update the application state when serving an ConnectorResource (such as ClassResource.getStream()).

  • Avoid (or be very careful when) updating application state in a TransactionListener - it is called even when the application is not locked and won't be serialized (such as with ConnectorResource), and changes can therefore be lost (it should be safe to update things that can be safely discarded later, that is, valid only for the current request).

  • The application remains locked during uploads - a progress bar is not possible.

Preface
I. Introduction
1. Introduction
1.1. Overview
1.2. Example Application Walkthrough
1.3. Support for the Eclipse IDE
1.4. Goals and Philosophy
1.5. Background
2. Getting Started with Vaadin
2.1. Overview
2.2. Setting up the Development Environment
2.3. Overview of Vaadin Libraries
2.4. Installing Vaadin Plugin for Eclipse
2.5. Creating and Running a Project with Eclipse
2.6. Using Vaadin with Maven
2.7. Creating a Project with NetBeans IDE
2.8. Creating a Project with IntelliJ IDEA
2.9. Vaadin Installation Package
2.10. Using Vaadin with Scala
3. Architecture
3.1. Overview
3.2. Technological Background
3.3. Client-Side Engine
3.4. Events and Listeners
II. Server-Side Framework
4. Writing a Server-Side Web Application
4.1. Overview
4.2. Building the UI
4.3. Handling Events with Listeners
4.4. Images and Other Resources
4.5. Handling Errors
4.6. Notifications
4.7. Application Lifecycle
4.8. Deploying an Application
5. User Interface Components
5.1. Overview
5.2. Interfaces and Abstractions
5.3. Common Component Features
5.4. Field Components
5.5. Component Extensions
5.6. Label
5.7. Link
5.8. TextField
5.9. TextArea
5.10. PasswordField
5.11. RichTextArea
5.12. Date and Time Input with DateField
5.13. Button
5.14. CheckBox
5.15. Selecting Items
5.16. Table
5.17. Tree
5.18. MenuBar
5.19. Embedded Resources
5.20. Upload
5.21. ProgressBar
5.22. Slider
5.23. Calendar
5.24. Component Composition with CustomComponent
5.25. Composite Fields with CustomField
6. Managing Layout
6.1. Overview
6.2. UI, Window, and Panel Content
6.3. VerticalLayout and HorizontalLayout
6.4. GridLayout
6.5. FormLayout
6.6. Panel
6.7. Sub-Windows
6.8. HorizontalSplitPanel and VerticalSplitPanel
6.9. TabSheet
6.10. Accordion
6.11. AbsoluteLayout
6.12. CssLayout
6.13. Layout Formatting
6.14. Custom Layouts
7. Visual User Interface Design with Eclipse
7.1. Overview
7.2. Creating a New Composite
7.3. Using The Visual Editor
7.4. Structure of a Visually Editable Component
8. Themes
8.1. Overview
8.2. Introduction to Cascading Style Sheets
8.3. Syntactically Awesome Stylesheets (Sass)
8.4. Creating and Using Themes
8.5. Creating a Theme in Eclipse
8.6. Responsive Themes
9. Binding Components to Data
9.1. Overview
9.2. Properties
9.3. Holding properties in Items
9.4. Creating Forms by Binding Fields to Items
9.5. Collecting Items in Containers
10. Vaadin SQLContainer
10.1. Architecture
10.2. Getting Started with SQLContainer
10.3. Filtering and Sorting
10.4. Editing
10.5. Caching, Paging and Refreshing
10.6. Referencing Another SQLContainer
10.7. Using FreeformQuery and FreeformStatementDelegate
10.8. Non-implemented methods of Vaadin container interfaces
10.9. Known Issues and Limitations
11. Advanced Web Application Topics
11.1. Handling Browser Windows
11.2. Embedding UIs in Web Pages
11.3. Debug Mode and Window
11.4. Request Handlers
11.5. Shortcut Keys
11.6. Printing
11.7. Google App Engine Integration
11.8. Common Security Issues
11.9. Navigating in an Application
11.10. Advanced Application Architectures
11.11. Managing URI Fragments
11.12. Drag and Drop
11.13. Logging
11.14. JavaScript Interaction
11.15. Accessing Session-Global Data
11.16. Server Push
12. Portal Integration
12.1. Overview
12.2. Creating a Portlet Project in Eclipse
12.3. Portlet UI
12.4. Deploying to a Portal
12.5. Installing Vaadin in Liferay
12.6. Handling Portlet Requests
12.7. Handling Portlet Mode Changes
12.8. Non-Vaadin Portlet Modes
12.9. Vaadin IPC for Liferay
III. Client-Side Framework
13. Client-Side Vaadin Development
13.1. Overview
13.2. Installing the Client-Side Development Environment
13.3. Client-Side Module Descriptor
13.4. Compiling a Client-Side Module
13.5. Creating a Custom Widget
13.6. Debugging Client-Side Code
14. Client-Side Applications
14.1. Overview
14.2. Client-Side Module Entry-Point
14.3. Compiling and Running a Client-Side Application
14.4. Loading a Client-Side Application
15. Client-Side Widgets
15.1. Overview
15.2. GWT Widgets
15.3. Vaadin Widgets
16. Integrating with the Server-Side
16.1. Overview
16.2. Starting It Simple With Eclipse
16.3. Creating a Server-Side Component
16.4. Integrating the Two Sides with a Connector
16.5. Shared State
16.6. RPC Calls Between Client- and Server-Side
16.7. Component and UI Extensions
16.8. Styling a Widget
16.9. Component Containers
16.10. Creating Add-ons
16.11. Migrating from Vaadin 6
16.12. Integrating JavaScript Components and Extensions
IV. Vaadin Add-ons
17. Using Vaadin Add-ons
17.1. Overview
17.2. Downloading Add-ons from Vaadin Directory
17.3. Installing Add-ons in Eclipse with Ivy
17.4. Using Add-ons in a Maven Project
17.5. Troubleshooting
18. Vaadin Charts
18.1. Overview
18.2. Installing Vaadin Charts
18.3. Basic Use
18.4. Chart Types
18.5. Chart Configuration
18.6. Chart Data
18.7. Advanced Uses
18.8. Timeline
19. Vaadin JPAContainer
19.1. Overview
19.2. Installing
19.3. Defining a Domain Model
19.4. Basic Use of JPAContainer
19.5. Entity Providers
19.6. Filtering JPAContainer
19.7. Querying with the Criteria API
19.8. Automatic Form Generation
19.9. Using JPAContainer with Hibernate
20. Mobile Applications with TouchKit
20.1. Overview
20.2. Considerations Regarding Mobile Browsing
20.3. Installing Vaadin TouchKit
20.4. Importing the Vornitologist Demo
20.5. Creating a New TouchKit Project
20.6. Elements of a TouchKit Application
20.7. Mobile User Interface Components
20.8. Advanced Mobile Features
20.9. Offline Mode
20.10. Building an Optimized Widget Set
20.11. Testing and Debugging on Mobile Devices
21. Vaadin TestBench
21.1. Overview
21.2. Installing Vaadin TestBench
21.3. Preparing an Application for Testing
21.4. Using Vaadin TestBench Recorder
21.5. Developing JUnit Tests
21.6. Taking and Comparing Screenshots
21.7. Running Tests in a Distributed Environment
21.8. Headless Testing
21.9. Known Issues
A. Songs of Vaadin
Index