GWT project directory creation by hand

Question

I am interested in writing a simple GWT application from scratch without the use of the Google Eclipse plugin or the applicationCreator in the GWT SDK. Why? Because I feel like it will help me really learn what these automated tools are doing under the hood, and will help my understand GWT that much better.

I did install the Google Eclipse plugin and used it to create a new Web Application Project (GWT app) just to see what kind of files it auto-generated. For my given project, which has a single module named WebModule (also acting as the sole EntryPoint of the app), here's what the Google Eclipse plugin gave me:

src/main/java
    com.myapp
        WebModule.gwt.xml
    com.myapp.client
        WebModule (implements EntryPoint)
    com.myapp.shared
    com.myapp.server
war/
    webModule/
        lots of folders and files under here...
        clear.cache.gif
        hosted.html
        webModule.nocache.js
    css/
        webModule.css
    hosts/
        webModule.html
    WEB-INF/
        web.xml
    deploy/
        webModule/
            rpcPolicyManifest/
                manifest.txt

So, what I'd like to do is recreate this in another project, but generate everything myself. In order to do that, I need to understand a few things, specifically:

1. What is the war/webModule directory, and what resources go there?
2. What is war/webModule/clear.cache.gif?
3. Is there any way to generate war/webModule/webModule.nocache.js myself? Or do I need to generate that from the command-line with one of the GWT SDK tools? (If so, what/how?)
4. What's the war/deploy directory? If I'm using RequestFactory instead of GWT-RPC do I need it?
5. Any other "essentials" I'm missing here?

Thanks in advance!

Answer 1

1 What is the war/webModule directory, and what resources go there?

This directory is the result of the GTW compiler:

• files *.cache.html are the versions for each locale and/or browser.
• *.cache.png are the images resources & sprites used by your application.
• If you use RPC there is also *.gwt.rpc for the (de)serialization mechanism.
• If you use a GWT theme, ie the clean theme, you have a gwt subdirectory with css & resources for this theme.

2 What is war/webModule/clear.cache.gif?

This is a 1x1 cacheable image used to have a placeholder for the <img> tag. See http://code.google.com/p/google-web-toolkit/wiki/ImageBundleDesign ("Clipping constructor for Image")

3 Is there any way to generate war/webModule/webModule.nocache.js myself? Or do I need to generate that from the command-line with one of the GWT SDK tools? (If so, what/how?)

*.nocache.js is generated by the GWT compiler. It is the application loader, which will choose the right locale/browser version of your application. It can be generated with the command line tool, an ant build file (see http://developers.google.com/web-toolkit/doc/latest/RefCommandLineTools for an example), or with maven.

4 What's the war/deploy directory? If I'm using RequestFactory instead of GWT-RPC do I need it?

This directory is generated with the -extra or -deploy option. It is files which are NOT deployed in production and contaning technical informations, for example:

• rpcPolicyManifest: contains metadata about RPC types used, and policies relative files path
• symbolMaps: data table to retrieve class names and stack trace from the obfuscated javascript files.

So I think if you don't use RPC, maybe you even need it to have unobfuscated traces.

5 Any other "essentials" I'm missing here?

You can find more details here: https://developers.google.com/web-toolkit/doc/latest/DevGuideCompilingAndDebugging

Hope this help...