How to use JESI control/include model to cache dynamic content
After completing this How-To you should be able to:
Know about the JESI control/include model to cache dynamic content
Use <jesi:control>, <jesi:include>,
<jesi:param> tags
Introduction
Oracle JESI tag library provides convenient interface
to ESI tags and Edge Sides Include functionality for Web caching. It provides
two models to cache dynamic content.
Control/ Include model
Template/ Fragment model
This How-To explains the Control/Include model. In
the control/ include model, the cacheable content is aggregated as included
pages from a top level page. The control/ include model is used as follows:
The top level page is cached using the <jesi:control>
tag
From the top level page, the content is aggregated using the <jesi:include>
tag.
While aggregating the content, the top level page and the included pages
are treated as individual documents. Hence, the included pages can be cached
separately using the <jesi:control> tag.
The example depicts the employee information system.
It accepts employee number and displays employee information for the given employee.
After generating the dynamic content for the given employee, the content can
be cached and served from the cache until it is invalidated. Following table
lists the web pages used in this sample and describes control/include model.
jesiinclude.html
Query page, which accepts employee number to fetch details about the employee.
Submit request from this page is sent to empdetails.jsp.
empdetails.jsp
This page is the top level page, which displays employee information.
This dynamic page can be cached once the content for the particular employee
is generated. <jesi:control> tag is used to cache this document.
The expiration value specifies how long the cached document should
stay in the cache. The maxRemovalDelay specifies how long the cached
content can be served stale after expiration.
While caching this page, the combination of the URL and the post request
(for eg. http://xyz.com/jesiinclude/empdetails.jsp
POST;;;empno=7369;;) will be used as the cache key for the document..
For any other employee say, emp no=7566, the content will be generated
again and cached.
From the top level page, the aggregate pages are included using the <jesi:include>
tag. JSP parameter values are passed to the aggregate page using the <jesi:param>
tag.
This page is the aggregate page. This is included from the empdetails.jsp
top level page. The aggregate pages are treated as separate documents. <jesi:control>
tag is used in this page to cache this document.
Pre-requisites for running the example
You will need the following to run this example -
Oracle Application Server (9.0.3 or above). This can be downloaded from
here
Oracle JDeveloper (9.0.3 or above). This can be downloaded from here.
This is optional and required only if you wish to deploy from JDeveloper.
Deploying the Sample
The complete source code for this sample is available
here. This section discusses the instruction to
run the sample application
Step 1
Unjar jesiinclude.jar
using Winzip, or using the following command:
> jar xvf jesiinclude.jar
This creates a directory jesiinclude.
Step 2
If you are using JDeveloper then, follow these steps
Open Oracle9i JDeveloper and use File/Open option to select the
jesiinclude.jws from the jesiinclude
directory.
Next, select Project/Make jesiinclude.jpr
from main menu.
Create an application server connection
Go to Connections -> Application Server Connection. Right Click
and click New connection..
In step 1, enter connection name and select Oracle9i Application
Server
In step 2, enter user name and password
In step 3, enter Enterprise Manager's host name, port number and
Remote Oracle AS home directory(required only if deployed on remote
machine).
In step 4, click Next and Test the connection. Click Finish button.
Now, Right click jesiinclude.deploy and
select Deploy to <connection name>, to the application server
connection, which you have created in the previous step.
Step 3
To deploy the application using EM. follow the
steps.
Go to EM web site -> default oc4j home.,
Choose Deploy EAR file
Enter J2EE Application name, Click the Browse button and choose jesiinclude.ear
from <SAMPLE_HOME>/deploy/jesiinclude.ear
Enter the Application name as jesiinclude and click next
Enter URL mapping as /jesiinclude and click Finish
Click Deploy to deploy the application.
Running the Sample
Access the page on the browser, using the following URL
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