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Implementing a new Enhancer

Implementing a new Enhancer

All enhancers need to implement the org.neuinfo.foundry.consumers.plugin.IPlugin interface which is located in the consumer-plugin-api subproject of the Foundry-ES. To develop a new enhancer, you need to include the Foundry-ES common and consumer-plugin-api libraries to your Maven pom.xml after you have built it via mvn -Pdev clean install in addition to all the dependencies from common/pom.xml of the Foundry-ES.

<dependency>
   <groupId>org.neuinfo</groupId>
   <artifactId>foundry-es-common</artifactId>
   <version>1.0-SNAPSHOT</version>
</dependency>
<dependency>
    <groupId>org.neuinfo</groupId>
    <artifactId>foundry-es-consumer-plugin-api</artifactId>
    <version>1.0-SNAPSHOT</version>
</dependency>

The org.neuinfo.foundry.consumers.plugin.IPlugin interface is shown below;

public interface IPlugin {

    public void setDocumentIngestionService(DocumentIngestionService dis);

    public void setGridFSService(GridFSService gridFSService);

    public void initialize(Map<String, String> options) throws Exception;

    public Result handle(DBObject docWrapper);

    public String getPluginName();

}

The enhancement is done in the handle(DBObject docWrapper) method which takes a Mongo DBObject object corresponding to the currently processed document wrapper from the Mongo database. If the original document is small (less than 1MB) it will be stored inline in the document wrapper otherwise it will be stored in the Mongo GridFS storage with a pointer in the document wrapper. Below is a code fragment to get the original document converted to JSON from the docWrapper regardless of where the original document is stored.

BasicDBObject data = (BasicDBObject) docWrapper.get("Data");
String originalFileIDstr = (String) docWrapper.get("originalFileId");
JSONObject json;
if (!Utils.isEmpty(originalFileIDstr)) {
   // large file
   Assertion.assertNotNull(this.gridFSService);
   json = gridFSService.findJSONFile(new ObjectId(originalFileIDstr));
} else {
   DBObject originalDoc = (DBObject) docWrapper.get("OriginalDoc");
   json = JSONUtils.toJSON((BasicDBObject) originalDoc, false);
}

The GridFS service org.neuinfo.foundry.common.ingestion.GridFSService and mongo document service org.neuinfo.foundry.common.ingestion.DocumentIngestionService are injected to the plugin by the ES-Foundry using the setters setGridFSService(GridFSService gridFSService) and setDocumentIngestionService(DocumentIngestionService dis) methods of the IPlugin interface.

If you want to work on and update/add to the transformed data prepared by the downstream enhancers in the pipeline which is stored under Data.transformedRec branch of the document wrapper, you can use the following code snippet to retrieve the transformed document;

BasicDBObject data = (BasicDBObject) docWrapper.get("Data");
BasicDBObject trDBO = (BasicDBObject) data.get("transformedRec");
JSONObject json = JSONUtils.toJSON(trDBO, false);

After you have done with enhancement, you can put back the enhanced JSON object and return the result using the following Java code snippet

BasicDBObject data = (BasicDBObject) docWrapper.get("Data");
BasicDBObject trDBO = (BasicDBObject) data.get("transformedRec");
JSONObject json = JSONUtils.toJSON(trDBO, false);

// enhancement of json

data.put("transformedRec", JSONUtils.encode(json, true));
return new Result(docWrapper, Result.Status.OK_WITH_CHANGE);

If there is an error occurred during the enhancement you need to return an error result as shown below;

Result r = new Result(docWrapper, Result.Status.ERROR);
r.setErrMessage(errorMessage);
return r;