| org.opencms.flex |
|
Provides low-level JSP integration funtionality for OpenCms,
also implements the FlexCache, a declarative parameter-based cache.
How the JSP integration is done:
In OpenCms all resources are residing in the OpenCms Database, the so
called "Virtual File System" or VFS.
However, all JSP engines available read the JSP code from a file in the local file system.
The option to re-write a JSP engine so that it can read from the VFS would limit OpenCms
to running with this JSP engine only, which was not a choice.
So the approach that was taken is to dump the contents of the OpenCms JSP page from the VFS
to the "real" file system
and then dispatch to the standard JSP engine.
Here is a top-level description of how this works:
- OpenCms gets the request through the {@link org.opencms.main.OpenCmsServlet}
- The requested resource is identified as a JSP page (resource type {@link org.opencms.file.types.CmsResourceTypeJsp})
- The JSP loader is started up with the resource manager {@link org.opencms.loader.CmsResourceManager}
- The JSP loader implements an additional interface: {@link org.opencms.loader.I_CmsResourceLoader}
- A resource loader is a new interface that was introduced with the FLEX release. The main
difference is that the original request / response is wrapped using a Servlet standard
{@link javax.servlet.http.HttpServletRequestWrapper} / {@link javax.servlet.http.HttpServletResponseWrapper}.
- On the first call to a page, the file contents of the JSP page are read from the OpenCms VFS
using the {@link org.opencms.file.CmsObject}
- The contents of the page are written to the "real" file system of the server,
in the default configuration to the directories
{WEBAPP-PATH}/opencms/WEB-INF/jsp/online or
{WEBAPP-PATH}/opencms/WEB-INF/jsp/offline (depending if the request was for the online or the offline
version of the page). The directory used can be configured in opencms.properties.
- After the page is written to the "real" FS, the loader dispatches to the standard JSP mechanism with a simple
include() call.
- The standard JSP mechanim will handle the JSP and deliver the output through the wrapped request / response
back to OpenCms.
- OpenCms will then deliver the contents back to the user.
@version $Revision: 1.12 $
@since 6.0.0
@see org.opencms.flex.CmsFlexCache
@see org.opencms.flex.CmsFlexCacheEntry
@see org.opencms.flex.CmsFlexCacheKey
|
| Java Source File Name | Type | Comment |
| CmsFlexCache.java | Class | This class implements the FlexCache.
The data structure used is a two-level hashtable.
This is optimized for the structure of the keys that are used to describe the
caching behaviour of the entries.
The first hash-level is calculated from the resource name, i.e. |
| CmsFlexCacheConfiguration.java | Class | |
| CmsFlexCacheEntry.java | Class | Contains the contents of a cached resource.
It is basically a list of pre-generated output,
include() calls to other resources (with request parameters) and http headers that this
resource requires to be set.
A CmsFlexCacheEntry might also describe a redirect-call, but in this case
nothing else will be cached.
The pre-generated output is saved in byte[] arrays. |
| CmsFlexCacheException.java | Class | |
| CmsFlexCacheKey.java | Class | |
| CmsFlexController.java | Class | |
| CmsFlexRequest.java | Class | |
| CmsFlexRequestContextInfo.java | Class | Contains information about the OpenCms request context required by the
Flex implementation.
An instance of this class is attached to every CmsRequestContext as
an attribute as soon as the request context is wrapped in a flex response. |
| CmsFlexRequestDispatcher.java | Class | Implementation of the
javax.servlet.RequestDispatcher interface to allow JSPs to be loaded
from the OpenCms VFS.
This dispatcher will load data from 3 different data sources:
- Form the "real" os File system (e.g.
|
| CmsFlexRequestKey.java | Class | |
| CmsFlexResponse.java | Class | |
| Messages.java | Class | |