Template-Based Code Generation using Spring batch

[4promachos]

I can manage to couple ItemReader using Spring batch and Apache Velocity .
It is possible to wrap VelocityEngine "replacement" within Spring batch ItemProcessor
My aim is to :
1/ start from a Reader (database,flat file...) [OK]

2/ treat it with ItemProcessor (the template base file) ; That's my question how to Wrap my VelocityEngineBean into a Composite Bean Spring containing ItemProcessor<T,V>
bellow a Snipset code coupling apache velocity and Spring batch, it would like to make a "farm ItemProcessor" of common treatement.

3/ generate N different Files according from the input .
(but can load dynamically the output writer ..with Spring Batch ? :confused



Here is my "Spring batch " config
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/p"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:batch="http://www.springframework.org/schema/batch"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:jms="http://www.springframework.org/schema/jms" xmlns:amq="http://activemq.apache.org/schema/core"
xmlns:util="http://www.springframework.org/schema/util"

xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schem...ring-beans.xsd

http://www.springframework.org/schema/batch http://www.springframework.org/schem...-batch-2.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schem...ng-context.xsd
http://www.springframework.org/schema/jms
http://www.springframework.org/schem...spring-jms.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
http://www.springframework.org/schema/util http://www.springframework.org/schem...pring-util.xsd
">


<!-- 1) USE ANNOTATIONS TO CONFIGURE SPRING BEANS -->
<context:component-scan base-package="com.batch.velocity.genClass" />


<bean id="velocityEngine"
class="org.springframework.ui.velocity.VelocityEng ineFactoryBean">
<property name="velocityProperties">
<value>
resource.loader=class
class.resource.loader.class=org.apache.velocity.ru ntime.resource.loader.ClasspathResourceLoader
</value>
</property>
</bean>




<bean id="itemReader" class="org.springframework.batch.item.file.FlatFil eItemReader">
<property name="resource" value="classpath:com/batch/velocity/genClass/dataTest.csv" />
<!-- property name="linesToSkip" value="1" /-->
<property name="lineMapper">
<bean class="org.springframework.batch.item.file.mapping .DefaultLineMapper">
<property name="lineTokenizer">
<bean class="org.springframework.batch.item.file.transfo rm.DelimitedLineTokenizer">
<!--<property name="delimiter" value="MonDel"/> -->
<property name="names" value="champ1,data1Type,documentation1,champ2,data 2Type,documentation2" />
</bean>
</property>
<property name="fieldSetMapper" ref="genMapperFactoryMapper" />
</bean>
</property>
</bean>
</beans>



/**
* Apache VELOCITY *.vm using VTL
*/
public class $name {


#foreach( $element in $mylist )

private $element.Data1Type $element.champ1;


/**
*
* Map : $element.champ1,$element.data1Type,$element.docume ntation1
* To : $element.champ2,$element.data2Type,$element.docume ntation2
* $element.documentation1
* @return the $element.champ1
*
*/
public $element.data1Type get${utility.getInputU($element.champ1)}() {
return $element.champ1;
}

/**
* Map : $element.champ1,$element.data1Type,$element.docume ntation1
* To : $element.champ2,$element.data2Type,$element.docume ntation2
* $element.documentation1
* @param $element.champ1 the $element.champ1 to set
* #set( $setter = "set" )
*/

public void set${utility.getInputU($element.champ1)}($element.data1Type $element.champ1) {
this.$element.champ1 = $element.champ1;
}

#end

}

package com.batch.velocity.genClass;

import org.apache.velocity.util.StringUtils;

public class GeneratorUtility {




/**
* set$utility.firstToUpperCase($att.Name)
* @param input the input to set
*/
public String getInputU(String pInput) {
pInput.split("_");
return StringUtils.capitalizeFirstLetter(pInput);
}
}




/***Test Junit ***/
package com.batch.velocity.genClass;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.velocity.app.VelocityEngine;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.batch.item.ExecutionContext;
import org.springframework.batch.item.ParseException;
import org.springframework.batch.item.UnexpectedInputExce ption;
import org.springframework.batch.item.file.FlatFileItemRe ader;
import org.springframework.beans.factory.annotation.Autow ired;
import org.springframework.test.context.ContextConfigurat ion;
import org.springframework.test.context.junit4.SpringJUni t4ClassRunner;
import org.springframework.ui.velocity.VelocityEngineUtil s;

import com.batch.velocity.Project;



@ContextConfiguration(locations = "classpath:com/batch/velocity/genClass/contextVelocity.xml")
@RunWith(SpringJUnit4ClassRunner.class)
public class VelocityCodeTemplateGenClassGenerator {



@Autowired
private VelocityEngine velocityEngine;

@Autowired
private FlatFileItemReader vFlatFileItemReader;

@Test
public void testFlatReaderItemToVelocityProcessor(){



System.out.println("[INFO] ----------------------------------------------------------------------------------");
System.out.println("[INFO] Running test : testFlatReaderItemToVelocityProcessor / "+ getClass().getName());
System.out.println("[INFO] ----------------------------------------------------------------------------------");



vFlatFileItemReader.open(new ExecutionContext());
boolean hasNext = true ;

GenMapperFactory vGenMapperFactory = null;

GeneratorUtility vUtility = new GeneratorUtility();
List<GenMapperFactory> vGenMapperFactoryList = new ArrayList<GenMapperFactory>();


//vMyClasseGen.setGenMapperFactory(new ArrayList<GenMapperFactory>());

while (hasNext) {
try {
vGenMapperFactory = (GenMapperFactory) vFlatFileItemReader.read();
vGenMapperFactoryList.add(vGenMapperFactory);

} catch (UnexpectedInputException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}


if (vGenMapperFactory == null) {
hasNext = false;

}
else {


Map model = new HashMap();

model.put("utility", vUtility);
model.put("mylist", vGenMapperFactoryList);
model.put("name", "ClassDeTest");

String text = VelocityEngineUtils.mergeTemplateIntoString(veloci tyEngine, "com/batch/velocity/genClass/example2.vm", model);
System.out.println(" "+text);

System.out.println(vGenMapperFactory.toString());
}
}
}

}


/**Fieldset Mapper Spring */

package com.batch.velocity.genClass;

import java.util.List;

import org.springframework.batch.item.file.mapping.FieldS etMapper;
import org.springframework.batch.item.file.transform.Fiel dSet;
import org.springframework.stereotype.Service;
import org.springframework.validation.BindException;
import com.batch.velocity.genClass.GenMapperFactory;


@Service("genMapperFactoryMapper")
public class GenMapperFactoryMapper implements FieldSetMapper<GenMapperFactory> {


public GenMapperFactory mapFieldSet(FieldSet fs) throws BindException {
GenMapperFactory item = new GenMapperFactory();

int idx = 0 ;

item.setChamp1(fs.readString("champ1"));
item.setData1Type(fs.readString("data1Type"));
item.setDocumentation1(fs.readString("documentatio n1"));
System.out.println("1:idx: > "+idx+" " +item.getChamp1()+ " | "+item.getData1Type()+" | "+item.getDocumentation1());


item.setChamp2(fs.readString("champ2"));
item.setData2Type(fs.readString("data2Type"));
item.setDocumentation2(fs.readString("documentatio n2"));
System.out.println("2:idx: > "+idx+" " +item.getChamp2()+ " | "+item.getData2Type()+" | "+item.getDocumentation2());

System.out.println(item.toString());

return item;
}

}