Sample code to use Amazon Comprehend Service for NLP - Tekraze.com

aws-comprehend-service.java

/***** Step 1 Imports *********/
import com.amazonaws.SdkClientException;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.client.builder.AwsClientBuilder.EndpointConfiguration;

import com.amazonaws.services.comprehend.AmazonComprehend;
import com.amazonaws.services.comprehend.AmazonComprehendClientBuilder;
import com.amazonaws.services.comprehend.model.DetectEntitiesRequest;
import com.amazonaws.services.comprehend.model.DetectEntitiesResult;
import com.amazonaws.services.comprehend.model.Entity;

/************* Step 2 *******************
** Initialize Amazon Comprehend Client
**************************************/
    AmazonComprehend comprehendClient() {
        log.debug("Intialize Comprehend Client");
        BasicAWSCredentials awsCreds = new BasicAWSCredentials(awsAccessKey, awsSecretKey);
        AWSStaticCredentialsProvider awsStaticCredentialsProvider = new AWSStaticCredentialsProvider(awsCreds);
        return AmazonComprehendClientBuilder.standard().withCredentials(awsStaticCredentialsProvider)
                .withRegion(awsRegion).build();
    }

/*****************Step 3**************
** Call Detect entities method **********/

public List<Entity> detectEntitiesWithComprehend(String text) {
        log.debug("Method to Detect Entities With Amazon Comprehend {}", blocksList.get(0));

        text = trimByBytes(textToAnalyze, 5000);
        DetectEntitiesRequest detectEntitiesRequest = new DetectEntitiesRequest().withText(text)
                .withLanguageCode("en");
        DetectEntitiesResult detectEntitiesResult = comprehendClient().detectEntities(detectEntitiesRequest);
        entitiesList = detectEntitiesResult.getEntities();
        return entitiesList;
    }

// Method to trim text to 500 bytes as Comprehend Sync Api Limit
     String trimByBytes(String str, int lengthOfBytes) {
        byte[] bytes = str.getBytes(StandardCharsets.UTF_8);
        ByteBuffer buffer = ByteBuffer.wrap(bytes);

        if (lengthOfBytes < buffer.limit()) {
            buffer.limit(lengthOfBytes);
        }

        CharsetDecoder decoder = StandardCharsets.UTF_8.newDecoder();
        decoder.onMalformedInput(CodingErrorAction.IGNORE);

        try {
            return decoder.decode(buffer).toString();
        } catch (CharacterCodingException e) {
            // We will never get here.
            throw new RuntimeException(e);
        }
    }