Below is my custom processor which selects data from mongoDB and write it in flowFile stream. Code is working fine but I need to modify the connection part so it uses connection pool instead of traditional connection. Similar to GetMongo processor
String db_name = "cms", host_name = "localhost";
MongoClient mongo_client = new MongoClient(host_name, 27017);
MongoDatabase db = mongo_client.getDatabase(db_name);How to achieve this,
Custom processor Below
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package test.processors.test2;
import com.mongodb.MongoClient;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import com.mongodb.client.MongoDatabase;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;
import org.apache.nifi.components.PropertyDescriptor;
import org.apache.nifi.flowfile.FlowFile;
import org.apache.nifi.annotation.behavior.ReadsAttribute;
import org.apache.nifi.annotation.behavior.ReadsAttributes;
import org.apache.nifi.annotation.behavior.WritesAttribute;
import org.apache.nifi.annotation.behavior.WritesAttributes;
import org.apache.nifi.annotation.lifecycle.OnScheduled;
import org.apache.nifi.annotation.documentation.CapabilityDescription;
import org.apache.nifi.annotation.documentation.SeeAlso;
import org.apache.nifi.annotation.documentation.Tags;
import org.apache.nifi.processor.exception.ProcessException;
import org.apache.nifi.processor.AbstractProcessor;
import org.apache.nifi.processor.ProcessContext;
import org.apache.nifi.processor.ProcessSession;
import org.apache.nifi.processor.ProcessorInitializationContext;
import org.apache.nifi.processor.Relationship;
import org.apache.nifi.processor.util.StandardValidators;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.io.OutputStreamWriter;
import org.apache.nifi.logging.ComponentLog;
import org.apache.nifi.processor.exception.FlowFileAccessException;
import org.bson.Document;
@Tags({"example"})
@CapabilityDescription("Provide a description")
@SeeAlso({})
@ReadsAttributes({
@ReadsAttribute(attribute = "", description = "")})
@WritesAttributes({
@WritesAttribute(attribute = "", description = "")})
public class MyProcessor extends AbstractProcessor {
public static final PropertyDescriptor MY_PROPERTY = new PropertyDescriptor.Builder().name("MY_PROPERTY")
.displayName("Prefix property")
.description("Prefix Property")
.required(true)
.addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
.build();
public static final Relationship REL_SUCCESS = new Relationship.Builder()
.name("Success")
.description("Sucessful relationship")
.build();
public static final Relationship REL_FAILURE = new Relationship.Builder()
.name("Fail")
.description("Failure relationship")
.build();
private List<PropertyDescriptor> descriptors;
private Set<Relationship> relationships;
@Override
protected void init(final ProcessorInitializationContext context) {
final List<PropertyDescriptor> descriptors = new ArrayList<PropertyDescriptor>();
descriptors.add(MY_PROPERTY);
this.descriptors = Collections.unmodifiableList(descriptors);
final Set<Relationship> relationships = new HashSet<Relationship>();
relationships.add(REL_SUCCESS);
relationships.add(REL_FAILURE);
this.relationships = Collections.unmodifiableSet(relationships);
}
@Override
public Set<Relationship> getRelationships() {
return this.relationships;
}
@Override
public final List<PropertyDescriptor> getSupportedPropertyDescriptors() {
return descriptors;
}
@OnScheduled
public void onScheduled(final ProcessContext context) {
}
@Override
public void onTrigger(final ProcessContext context, final ProcessSession session) throws ProcessException {
FlowFile flowFile = session.get();
if (flowFile == null) {
return;
}
final ComponentLog logger = getLogger();
final String prefixStr = context.getProperty(MY_PROPERTY).getValue();
try {
flowFile = session.write(flowFile, (final InputStream inputStream, final OutputStream outputStream) -> {
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, StandardCharsets.UTF_8));
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, StandardCharsets.UTF_8));
String line;
while ((line = bufferedReader.readLine()) != null) {
String xxx = mongoDB( prefixStr, line);
String aggregatedText = prefixStr + ": " + line + ": " + xxx;
bufferedWriter.write(aggregatedText);
bufferedWriter.newLine();
}
bufferedWriter.flush();
});
session.transfer(flowFile, REL_SUCCESS);
logger.info("successfully processed FlowFile {}", new Object[]{flowFile});
} catch (FlowFileAccessException e) {
session.transfer(flowFile, REL_FAILURE);
logger.info("Failed to add prefix for FlowFile: " + e.getMessage());
}
}
String db_name = "cms", host_name = "localhost";
MongoClient mongo_client = new MongoClient(host_name, 27017);
MongoDatabase db = mongo_client.getDatabase(db_name);
public String mongoDB(String arg1, String arg2) {
final ComponentLog logger = getLogger();
String result = "";
try {
String db_col_name = arg1;
MongoCollection<Document> coll = db.getCollection(db_col_name);
Document query = new Document();
query.put("msisdn", arg2);
logger.info(query.toJson());
FindIterable<Document> fi = coll.find(query);
try (MongoCursor<Document> cursor = fi.iterator()) {
while (cursor.hasNext()) {
result = result + cursor.next().toJson();
}
}
}
catch (Exception e)
{
logger.info("Error: " + e.getMessage());
}
return result;
}
}
