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<h:commandLink
	action="#{org.jboss.seam.excel.excelExporter.export('form:dataTable')}">
	<h:graphicImage value="/img/excel.gif" />
 </h:commandLink>

where form is the form id and ‘datatable’ is the id of the datatable in that form. Thats as simple as it can get! If you want a customized excel, then writing the excel layout, formatting by hand does not use java code at all! Everything can be coded on plain facelet tags. To demonstrate how easy it is, to create excel spreadsheets on the fly, look at this example

 <e:workbook type="jxl" xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:e="http://jboss.com/products/seam/excel"
    xmlns:f="http://java.sun.com/jsf/core"
    autoFilterDisabled="false">

    <e:cellTemplate name="cellStyles">
        <e:background color="gray_25" pattern="solid"/>
        <e:font fontName="Lucida Grande" bold="true"/>
    </e:cellTemplate>

   <e:worksheet name="Search Criteria" value="#{searchCriteriaList}" var="criteria">
    <e:column autoSize="true">
        <f:facet name="header">
            <e:cell value="Time Period" templates="cellStyles"/>
        </f:facet>
        <e:cell value="#{criteria.timePeriod}" />
    </e:column>
    <e:column autoSize="true">
        <f:facet name="header">
            <e:cell value="Foo name" templates="cellStyles"/>
        </f:facet>
        <e:cell value="#{criteria.foo.name}" />
    </e:column>
    <e:column autoSize="true">
        <f:facet name="header">
            <e:cell value="Bar Name" templates="cellStyles"/>
        </f:facet>
        <e:cell value="#{criteria.bar.name}"/>
    </e:column>
</e:worksheet>

<e:worksheet name="Matrix" value="#{searchResults}" var="res"  headerMargin="5"
	verticalFreeze="1" selected="true" showGridLines="true" topMargin="5">
	<e:column autoSize="true">
		<f:facet name="header">
			<e:cell value="FooName" templates="cellStyles"/>
		</f:facet>
		<e:cell value="#{res.foo.name}" />
	</e:column>
	<e:column autoSize="true">
		<f:facet name="header">
			<e:cell value="Bar name" templates="cellStyles"/>
		</f:facet>
		<e:cell value="#{res.bar.name}"/>
	</e:column>
</e:worksheet>
</e:workbook>                                                                                                                                                                                                                         	         		 			           		 		 	 	 		 			                      		 		 		     

The syntax is so simple, even a layman can understand. As you’ve seen, I’ve created two worksheets, the first one displaying the search criteria and the second one displaying the results (List : foo, bar, timePeriod). For common formatting features, you can use a feature called “templates” (see “cellStyles” above). he formatting of excel goes way beyond simple example like above to things like built in formulas, auto filters etc.

The Seam-excel support is built in the 2.1 beta release

We can’t have a local database instance running and having a hsqldb or mysql database would not really give us the confidence of working in the “actual world.” So, How can you have a local Oracle database without all that fuss?

Here is an alternative that I tried and it worked like a charm for me.

1) Install Oracle 10G XE . Its a light-weight version of 10G and its *free*. There is no configuration whatsoever, just the password for admin username, “system”

2) After installation you’re basically done. I use Open Oracle SQLDeveloper for the client. I think its simple and does everything you need. And its *free*. Make a new connection with
host – localhost, port – 1521, SID – xe

Surprisingly, all the above are provided by default! Now, setup a new user for your application. Grant “all” rights.

3) In my web application, I use a top-down approach with a rich domain model with JBoss Seam Framework where the schema is 100% generated by hbm2ddl. For static data, I have an import.sql in the web-inf. All I need to do is, change the hibernate.hbm2ddl.auto value back to “create” (it was “validate” before)

And change the datasource connection to jdbc:oracle:thin:@localhost:1521/xe in the jndi datasource in jboss server.

4) Change the jboss http port from 8080 to 8081 from here
jboss-4.2.2\server\default\deploy\jboss-web.deployer\server.xml
(as oracle server uses the same)

5) Start JBoss server

That’s it. All in all, it took around 20-25 minutes. (including the installation)

I now have a new oracle database installed, new tables created, new static data setup and most importantly — I did not add any configuration file(s) whatsoever and nothing in my app was changed except the ds file (which again is outside the ear file). I did not run any ruby scripts, nor groovy scripts and No — I didn’t call my DBA to setup the database or run some data scripts for me.

And the application deployed SUCCESSFULLY.

All this in less than 25 minutes.

This,, I think is agile Domain Driven Development using Seam framework.

I’m wondering if I could’ve done this 5 years ago. Not without hiring a consultant for a project named “database migration.” and not without changing so many files.

import java.util.Collection;
import javax.interceptor.AroundInvoke;
import javax.interceptor.InvocationContext;
import org.apache.commons.lang.time.StopWatch;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class StatisticsInterceptor {
	private static final Log log = LogFactory
			.getLog(StatisticsInterceptor.class);

	@AroundInvoke
	@SuppressWarnings("unchecked")
	public Object intercept(InvocationContext ctx) throws Exception {
		StopWatch stopWatch = new StopWatch();
		stopWatch.start();
		Object result = ctx.proceed();
		log.debug("Statistics for "
				+ ctx.getMethod().getDeclaringClass().getSimpleName() + "."
				+ ctx.getMethod().getName());
		log.debug("\tTime = " + stopWatch);
		if (result instanceof String) {
			log.debug("\tValue returned = " + result);
		}
		if (result instanceof Collection) {
			Collection col = (Collection) result;
			log.debug("\tSize of collection returned = " + col.size());
		}
		return result;
	}
}

The only place, this needs to be added is in ejb-jar.xml

<assembly-descriptor>
      <interceptor-binding>
         <ejb-name>*</ejb-name>
         <interceptor-class>org.jboss.seam.ejb.SeamInterceptor</interceptor-class>
      </interceptor-binding>
      <interceptor-binding>
         <ejb-name>*</ejb-name>
         <interceptor-class>com.evergreen.asr.util.StatisticsInterceptor</interceptor-class>
      </interceptor-binding>
   </assembly-descriptor>

That’s it.