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*Author:* Craig Stancl
*Email:* Stancl.craig@mayo.edu
*Team:* LexEVS
*Contract:* CBITT BOA Subcontract# 29XS223
*Client:* NCI CBIIT
National Institutes of Heath
US Department of Health and Human Services
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*Revision History*
|| Version || Date || Description of Changes  \\ || Author \\ ||
| 1.0 | 5/14/10 \\ | Initial Version Approved via Design Review | Team \\ |

In order to facilitate extra Processing at the end of an Ontology load, LexEVS 6.0 will support _Loader Post Processors_.

A Loader Post Processor is logic that will be executed when the actual content load to the database is complete, but before the Lucene Indexing occurs. It will be implemented as an _Extension_ \- meaning that users may place jars in the LexEVS class path and introduce Loader Post Processors without the need to recompile.

The Loader Post Processor interface is straightforward:
{code}
public interface LoaderPostProcessor extends GenericExtension {

public void runPostProcess(AbsoluteCodingSchemeVersionReference reference);
}
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{note:title=Note}This is considered a _GenericExtension_ and must be registered and declared as such. A Loader Post Processor may apply any logic that is required \-\- there are not constraints as to the scope. A Loader Post Processor may update database content, delete content, reference other loaded ontologies, etc.{note}

An example Loader Post Processor is shown below \-\- this example will update the Approximate Number of Loaded Entities field of a Coding Scheme:
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package org.LexGrid.LexBIG.Impl.loaders.postprocessor;

import org.LexGrid.LexBIG.DataModel.Core.AbsoluteCodingSchemeVersionReference;
import org.LexGrid.LexBIG.DataModel.InterfaceElements.ExtensionDescription;
import org.LexGrid.LexBIG.Exceptions.LBException;
import org.LexGrid.LexBIG.Exceptions.LBParameterException;
import org.LexGrid.LexBIG.Extensions.Generic.GenericExtension;
import org.LexGrid.LexBIG.Extensions.Load.postprocessor.LoaderPostProcessor;
import org.LexGrid.LexBIG.Impl.Extensions.AbstractExtendable;
import org.LexGrid.LexBIG.Impl.Extensions.ExtensionRegistryImpl;
import org.LexGrid.codingSchemes.CodingScheme;
import org.lexevs.dao.database.service.codingscheme.CodingSchemeService;
import org.lexevs.dao.database.service.entity.EntityService;
import org.lexevs.locator.LexEvsServiceLocator;

public class ApproxNumOfConceptsPostProcessor extends AbstractExtendable implements LoaderPostProcessor {

private static final long serialVersionUID = 2828520523031693573L;

public static String EXTENSION_NAME = "ApproxNumOfConceptsPostProcessor";

public void register() throws LBParameterException, LBException {
   ExtensionRegistryImpl.instance().registerGenericExtension(
      super.getExtensionDescription());
   }

   @Override
   protected ExtensionDescription buildExtensionDescription() {
       ExtensionDescription ed = new ExtensionDescription();
       ed.setDescription("ApproxNumOfConceptsPostProcessor");
       ed.setName(EXTENSION_NAME);
       ed.setExtensionBaseClass(GenericExtension.class.getName());
       ed.setExtensionClass(this.getClass().getName());

       return ed;
   }

   public void runPostProcess(AbsoluteCodingSchemeVersionReference reference) {
       EntityService entityService = LexEvsServiceLocator.getInstance().getDatabaseServiceManager().getEntityService();
       CodingSchemeService codingSchemeService = LexEvsServiceLocator.getInstance().getDatabaseServiceManager().getCodingSchemeService();

       String uri = reference.getCodingSchemeURN();
       String version = reference.getCodingSchemeVersion();

       long entities = entityService.getEntityCount(uri, version);

       CodingScheme codingScheme = codingSchemeService.getCodingSchemeByUriAndVersion(uri, version);

       codingScheme.setApproxNumConcepts(entities);

       codingSchemeService.updateCodingScheme(uri, version, codingScheme);
   }
}
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