This section introduces the gql() and gqlStream() methods on a Connection object for querying the database using GQL.

Each example focuses solely on the method's usage. For a complete code example, please refer to the full example.

GQL (Graph Query Language) is the ISO-standard query language for graph databases. For detailed information on GQL, refer to the documentation.

gql()

Executes a GQL query on the current graphset or the database and returns the result.

Parameters:

• String: The GQL query to be executed.
• RequestConfig (Optional): Configuration settings for the request.

Returns:

• Response: Result of the request.

// Retrieves 5 nodes labeled 'movie' in graphset 'miniCircle' and prints their names

RequestConfig requestConfig = new RequestConfig();
requestConfig.setGraphName("miniCircle");

Response response = client.gql("MATCH (n:movie) RETURN n LIMIT 5", requestConfig);
List<Node> nodeList = response.alias("n").asNodes();
for (Node node : nodeList) {
    System.out.println(node.get("name"));
}

The Shawshank Redemption
Farewell My Concubine
Léon: The Professional
Titanic
Life is Beautiful

For more examples, please refer to Types Mapping Ultipa and Java.

gqlStream()

Executes a GQL query on the current graphset or the database and returns the result incrementally, allowing handling of large datasets without loading everything into memory at once.

Parameters:

• String: The GQL query to be executed.
• GqlListener: Listener for the streaming process.
• RequestConfig (Optional): Configuration settings for the request.

Returns:

• void

// Retrieves all 1-step paths in graphset 'miniCircle'

RequestConfig requestConfig = new RequestConfig();
requestConfig.setGraphName("miniCircle");

client.gqlStream("MATCH paths = ()-[]-() RETURN paths", new GqlListener() {
    int count = 0;

    public void onReady() {
        System.out.println("Start downloading");
    }

    public void next(Response response) {
        if (response.getStatus().getErrorCode() != Ultipa.ErrorCode.SUCCESS){
            System.out.println(response.getStatus().getMsg());
        }
        List<Path> paths = response.get(0).asPaths();
        count += paths.size();
        System.out.println("count = " + count);
    }

    public void onComplete() {
        System.out.println("Done");
        System.out.println("count = " + count);
    }

    public void onError(Throwable throwable) {
        System.out.println("Error");

    }
}, requestConfig);

count = 1250
count = 1392
Done
count = 1392

Full Example

package com.ultipa.www.sdk.api;

import com.ultipa.sdk.connect.Connection;
import com.ultipa.sdk.connect.conf.RequestConfig;
import com.ultipa.sdk.connect.conf.UltipaConfiguration;
import com.ultipa.sdk.connect.driver.UltipaClientDriver;
import com.ultipa.sdk.operate.entity.*;
import com.ultipa.sdk.operate.response.Response;
import java.util.*;

public class Main {
    public static void main(String[] args) {
         // Connection configurations
        UltipaConfiguration myConfig = UltipaConfiguration.config()
            // URI example: .hosts("mqj4zouys.us-east-1.cloud.ultipa.com:60010")
            .hosts("192.168.1.85:60061,192.168.1.86:60061,192.168.1.87:60061")
            .username("<username>")
            .password("<password>");

        UltipaClientDriver driver = null;
        try {
            // Establishes connection to the database
            driver = new UltipaClientDriver(myConfig);
            Connection client = driver.getConnection();
          
            // Request configurations
            RequestConfig config = new RequestConfig();
            config.setGraphName("amz");
            
            // Retrieves 10 nodes and prints the _id and storeName property value of the first returned one
            Response response = client.gql("MATCH (n) RETURN n LIMIT 10");
            List<Node> nodeList = response.alias("n").asNodes();
            System.out.println("ID of the 1st node: " + nodeList.get(0).getID());
            System.out.println("Store name of the 1st node: " + nodeList.get(0).get("storeName"));
        } finally {
            if (driver != null) {
                driver.close();
            }
        }
    }
}