Struts 2.3.x: Tiles plugin upgrade

[lukaszlenart]

Fixes WW-4568

This PR upgrades the Tiles Plugin and adjusts its API to be compatible with Tiles 2.2.2 - this allows introduce support for OGNL, EL, Wildcards and so on.

[cnenning]

For struts 2.3 I still got an old app with tiles2 which does some custom stuff and which has issues with these changes.

• tiles-servlet-wildcard depends on spring-web. That causes spring to be pulled in to all apps that use struts-tiles-pluign. Due to this I would prefer wildcard support could be optional
• in TilesContainerFactory.createContainerFactory() it is necessary for me to register tilesContainer in servletContext. Can be done like this, would you mind adding this to StrutsTilesContainerFactory?

@Override
protected BasicTilesContainer instantiateContainer(TilesApplicationContext applicationContext) {
    CachingTilesContainer tilesContainer = new CachingTilesContainer();
    ServletContext servletContext = (ServletContext) applicationContext.getContext();
    ServletUtil.setContainer(servletContext, tilesContainer);
    return tilesContainer;
}

• in StrutsTilesContainerFactory.getSourceURLs() these two resource patterns are used: /WEB-INF/**/tiles*.xml and classpath*:META-INF/**/tiles*.xml. The 2nd one causes an exception in WebSphere with IBM JDK. Would be nice if we could make this configurable. The exception is Caused by: java.net.MalformedURLException: SRVE0238E: Resource paths should have a leading slash

Currently I have created my own TilesListener, TilesInitializer and TilesContainerFactory. With the above changes I could avoid that and just stick to StrutsTilesListener.

Two minor things I noticed in showcase app:

• It logs this message: WARN (freemarker.jsp:75) - Custom EL functions won't be loaded because no ObjectWarpper was specified . So it may be that tiles-el along with tiles-freemarker are not working?
• css layout seems to be broken in firefox (surely not related to this PR, looks good in chrome and ie11, is fixed in master branch)

[lukaszlenart]

@cnenning thanks for a really good feedback. I implemented a dedicated ApplicationContext to support wildcard matching without depending on Spring - by default all tiles*.xml will be loaded.

After cleaning up dependencies I didn't notice the issue with EL, could you check that on your side?

Thanks!

[cnenning]

The new version looks awesome!

Just a small addon to constructor of StrutsWildcardServletTilesApplicationContext, that re-enables loading of tiles*.xml from classpath and works in IBM stuff, too:

        Enumeration<URL> cpResources = getClass().getClassLoader().getResources("/");
        while (cpResources.hasMoreElements()) {
            URL cpResource = cpResources.nextElement();
            urls.add(cpResource);
        }

Regarding the other issues:

• css looks alright again in FF, seems like it was a FF bug
• About EL stuff: I'm pretty helpless and pretty confused. That log message is created in freemarker.ext.jsp.TaglibFactory. It looks for a BeansWrapper which struts creates in FreemarkerManager.createObjectWrapper(). When tiles-layout is created with a JSP, and just tiles-attributes are done with FTLs everything seems OK. But when tiles-layout is done with FTL that message is logged and EL support seems broken.

[lukaszlenart]

I still cannot reproduce the issue with missing support for EL, here is my example I have been using to test this PR

https://github.com/lukaszlenart/struts2-tiles-demo

[cnenning]

https://github.com/lukaszlenart/struts2-tiles-demo

I created a PR for that demo app which demonstrates the issue.

See https://github.com/lukaszlenart/struts2-tiles-demo/pull/2

[lukaszlenart]

This is what I get (I have been using Jetty)

[cnenning]

This is what I get (I have been using Jetty)

Hmm, the freemarker template is not executed but it's code is shown. This is another issue. No idea why that happens.

[cnenning]

I would say we merge this and may fix the "EL not working in freemarker-insert with freemarker-template" issue in master.

[lukaszlenart]

Let's do it, at least I will have less problem with debugging :D