Stargate Software Development Kit

This SDK (Software Development Kit) makes it easy to call Stargate services using idiomatic Java APIs.

1.1 - Overview
1.2 - APIs descriptions

2.1 - Prerequisites
2.2 - Start Stargate
2.3 - QuickStart
2.4 - Working with Rest API
2.5 - Working with Document API
2.6 - Working with GRPC API
2.7 - Working with Graph API
2.8 - Working with Json API

1. Introducing Stargate

1.1 Overview

Stargate is a data API gateway that deploys between your apps and your Apache Cassandra database(s). Stargate is a framework used to customize all aspects of data access. It is deployed between client applications and a database to provide an abstraction layer that can be used to shape your data access to fit your application’s needs.

Stargate exposes multiple APis to access data stored in Cassandra, including REST, GraphQL, and schemaless Document APIs. This SDK provides a Java API to access to all of them.

1.2 Api Descriptions

API	Description
CQL	Stargate functions as a Cassandra node, allowing existing Cassandra drivers to be utilized for connections. The primary goal is to minimize the number of open connections by enabling clients to connect only to Stargate, rather than directly to the Cassandra data nodes. This approach also serves as an effective method to separate computing and storage components.
JSON API	Mongoose compatible Http API exposing operation to use Cassandra as a document database. It should be consider and an upgrade to the previously discussed document API. It also introduces support for vectors and semantic searches.
REST	Stargate is a data gateway deployed between client applications and a database. The REST API exposes CRUD access to data stored in Cassandra tables.
Document	Stargate serves as a data gateway positioned between client applications and a database. It features the Stargate Document API, which enables the modification and querying of data stored in the form of unstructured JSON documents within collections. A key advantage of the Document API is its schema-less nature, eliminating the need for data modeling. When integrated with Apache Cassandra, the Document API leverages Cassandra's secondary indexes for document indexing. Conversely, when used in conjunction with DataStax Enterprise, it utilizes SAI indexing for this purpose. Further insights into the architecture and storage methodologies of collections can be found in the blog post 'The Stargate Cassandra Documents API.
GraphQL	API implementation for exposing Cassandra data over GraphQL. The Stargate GraphQL API is implemented to easily modify and query your table data using GraphQL types, mutations, and queries with any Cassandra deployment. The Stargate GraphQL API has two modes, one developed from native GraphQL schema principles, and one developed with the Cassandra Query Language (CQL) in mind. To distinguish these two modes, the rest of the documentation will refer to the modes as schema-first and cql-first. The CQL-first approach directly translates CQL tables into GraphQL types, mutations, and queries. The GraphQL schema is automatically generated from the keyspace, tables, and columns defined, but no customization is allowed. A standard set of mutations and queries are produced for searching and modifying the table data. If you are familiar with Cassandra, you might prefer this approach. The schema-first approach allows you to create idiomatic GraphQL types, mutations, and queries in a manner familiar to GraphQL developers. The schema is deployed and can be updated by deploying a new schema without recreating the tables and columns directly. Under the covers, this approach will create and modify the CQL tables to match the GraphQL types. The schema can be modified for CQL decorated schema, such as specifying table and column names in Cassandra, while retaining GraphQL-centric names for the types that correspond. If you are a GraphQL developer, this approach is for you.
GRPC	Stargate is a data gateway deployed between client applications and a database. gRPC is a modern, open source remote procedure call (RPC) framework. It enables client and server applications to communicate transparently, and makes it easier to build connected systems. The Stargate gRPC API is implemented to create language-specific queries using CQL with any Cassandra deployment.

2. Stargate SDK

2.1 Prerequisites

📦 Docker

Use the reference documentation to install Docker Desktop
Validate your installation with

docker -v
docker run hello-world

📦 Java Development Kit (JDK) 8+

Use the reference documentation to install a Java Development Kit
Validate your installation with

java --version

📦 Apache Maven

Use the reference documentation to install Apache Maven
Validate your installation with

mvn -version

🏠 Back to Table of Contents

2.2 Start Stargate

✅ Use the script start.sh at root of the repository or start stargate with the following docker-compose command:

docker-compose -f ./stargate-sdk-test/src/test/resources/docker-compose.yml up -d

Expected output

[+] Building 0.0s (0/0)                                                                                                    docker:desktop-linux
[+] Running 6/6
 ✔ Network resources_stargate         Created                                                                                              0.0s 
 ✔ Container resources-coordinator-1  Healthy                                                                                              0.0s 
 ✔ Container resources-jsonapi-1      Started                                                                                              0.0s 
 ✔ Container resources-restapi-1      Started                                                                                              0.0s 
 ✔ Container resources-graphqlapi-1   Started                                                                                              0.0s 
 ✔ Container resources-docsapi-1      Started                                                                                              0.0s

With development mode enabled, Stargate also plays the role of a data node, as such you do not need any extra Cassandra container.

Multiple ports have been declared are here what they are used for. The tools listed here (playground, swagger-ui( will be available about 40s after the docker run commmand.

8080 is the Graphql port you can access the playground on http://localhost:8080/playground
8081 is the Authentication port to retrieve a your token based on user/password
8082 is the Rest API port. You can access Swagger documentation on http://localhost:8082/swagger-ui/#/ also the health check is done through http://localhost:8082/health
8181 is the Json Api port. You can access Swagger documentation on http://localhost:8181/swagger-ui/#/ also the health check is done through http://localhost:8181/health
8090 is the Grpc port. A socket is open listening from Grpc calls.
9042 is the default CQL port. A socker is open listening CQL calls coming from the native drivers.

2.3. Quickstart

✅ Create the project sdk-quickstart-stargate with a maven archetype:

mvn archetype:generate \
  -DarchetypeGroupId=org.apache.maven.archetypes \
  -DarchetypeArtifactId=maven-archetype-quickstart \
  -DarchetypeVersion=1.4 \
  -DgroupId=com.datastax.tutorial \
  -DartifactId=sdk-quickstart-stargate \
  -Dversion=1.0.0-SNAPSHOT \
  -DinteractiveMode=false

✅ Import the project favorite IDE, and replace the pom.xml with the following XML.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" 
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.datastax.tutorial</groupId>
  <artifactId>sdk-quickstart-stargate</artifactId>
  <version>1.0.0-SNAPSHOT</version>
  <name>sdk-quickstart-stargate</name>
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>
  <dependencies>
    <dependency>
	  <groupId>com.datastax.stargate</groupId>
	  <artifactId>stargate-sdk</artifactId>
	  <version>0.2.5</version>
    </dependency>
  </dependencies>
</project>

✅ Delete folder src/test/java, we will experiment with a main class.

ℹ️ Informations:

We removed the Junit classes generated as we will work a main class.
We added the latest version of stargate-sdk dependency. The xml below may no be up-to-date.

✅ Initialize Stargate client

StargateClient is the class you will have to work with, from there you leverage on a fluent api.

Rename App.java to QuickstartStargate.java and update the class accordingly.

public static void main(String[] args) {
  try (StargateClient stargateClient = configureStargateClient()) {
    // work with Stargate
  }
}
public static StargateClient configureStargateClient() {
  return StargateClient.builder()
    .withCqlContactPoints("localhost:9042")
    .withLocalDatacenter("datacenter1")
    .withAuthCredentials("cassandra", "cassandra")
    .withApiNode(new StargateNodeConfig("127.0.0.1"))
    .build();
}

ℹ️ Informations

Based on parameters provided in the builder, the 5 apis (cql,rest,doc,graphQL,grpc) will be enabled of not.
As CqlSession is stateful you need to close it at the application shutdown. StargateClient is no different, if you enable Cql api, you need to close it at the application shutdown. To cope with this constraint the class is Autocloseable.
Cql: needs contact-points, localdatacenter and credentials. If not provided the default values for contact points is localhost:9042
Https Api need the hostname, port numbers and credentials. But if you are using the default ports no need to specified them.

✅ Execute the main class `QuickstartStargate.java`

To run the application you can either use your IDE or maven

mvn exec:java -Dexec.main=com.datastax.tutorial.QuickstartStargate

👁️ Expected output

INFO �com.datastax.stargate.sdk.StargateClient       �: Initializing [StargateClient]
INFO �com.datastax.stargate.sdk.StargateClient       �: + Stargate nodes #[1] in [datacenter1]
INFO �com.datastax.stargate.sdk.StargateClient       �: + CqlSession   :[ENABLED]
INFO �com.datastax.stargate.sdk.rest.ApiDataClient   �: + API Data     :[ENABLED]
INFO �com.datastax.stargate.sdk.doc.ApiDocumentClient�: + API Document :[ENABLED]
INFO �com.datastax.stargate.sdk.gql.ApiGraphQLClient �: + API GraphQL  :[ENABLED]
INFO �com.datastax.stargate.sdk.grpc.ApiGrpcClient �. : + API Grpc     :[ENABLED]
INFO �com.datastax.stargate.sdk.StargateClient       �: Closing CqlSession.

✅ Check you can invoke each Api. Add the following utilities methods in `QuickstartStargate.java`

public static void testCqlApi(StargateClient stargateClient) {
  CqlSession cqlSession = stargateClient.cqlSession().get();
  System.out.println("Cql Version (cql)   : " + cqlSession
    .execute("SELECT cql_version from system.local")
    .one().getString("cql_version"));
}
    
public static void testRestApi(StargateClient stargateClient) {
  System.out.println("Keyspaces (rest)    : " + 
    stargateClient.apiRest()
                  .keyspaceNames()
                  .collect(Collectors.toList()));
}
    
public static void testDocumentaApi(StargateClient stargateClient) {
  System.out.println("Namespaces (doc)    : " + 
    stargateClient.apiDocument()
                  .namespaceNames()
                  .collect(Collectors.toList()));
}
    
public static void testGraphQLApi(StargateClient stargateClient) {
  System.out.println("Keyspaces (graphQL) : " + 
    stargateClient.apiGraphQL().cqlSchema().keyspaces());
}
    
public static void testGrpcApi(StargateClient stargateClient) {
  System.out.println("Cql Version (grpc)  : " + 
    stargateClient.apiGrpc()
                  .execute("SELECT cql_version from system.local")
                  .one().getString("cql_version"));
}

✅ Update the `main` method accordingly:

public static void main(String[] args) {
   try (StargateClient stargateClient = configureStargateClientDefault()) {
      testCqlApi(stargateClient);
      testRestApi(stargateClient);
      testDocumentaApi(stargateClient);
      testGraphQLApi(stargateClient);
      testGrpcApi(stargateClient);
   }
}

✅ Execute the main class `QuickstartStargate.java` again

👁️ Expected output

INFO �com.datastax.stargate.sdk.StargateClient       �: Initializing [StargateClient]
INFO �com.datastax.stargate.sdk.StargateClient       �: + Stargate nodes #[1] in [datacenter1]
INFO �com.datastax.stargate.sdk.StargateClient       �: + CqlSession   :[ENABLED]
INFO �com.datastax.stargate.sdk.rest.ApiDataClient   �: + API Data     :[ENABLED]
INFO �com.datastax.stargate.sdk.doc.ApiDocumentClient�: + API Document :[ENABLED]
INFO �com.datastax.stargate.sdk.gql.ApiGraphQLClient �: + API GraphQL  :[ENABLED]
INFO �com.datastax.stargate.sdk.grpc.ApiGrpcClient �. : + API Grpc     :[ENABLED]
Cql Version (cql)   : 3.4.4
Keyspaces (rest)    : [system_distributed, system, data_endpoint_auth, system_schema, java, stargate_system, system_auth, system_traces]
Namespaces (doc)    : [system_distributed, system, data_endpoint_auth, system_schema, java, stargate_system, system_auth, system_traces]
Keyspaces (graphQL) : {"data":{"keyspaces":[{"name":"system_distributed"},{"name":"system"},{"name":"data_endpoint_auth"},{"name":"system_schema"},{"name":"java"},{"name":"stargate_system"},{"name":"system_auth"},{"name":"system_traces"}]}}
Cql Version (grpc)  : 3.4.4
INFO �com.datastax.stargate.sdk.StargateClient       �: Closing CqlSession.

ℹ️ Reminder: You can download the code here 📥 Download

Congratulations: you are ready to explore each Api leveraging the fluent api. |

2.4. Working with Rest API

Related Api Reference documentation and endpoints can be found there

`ApiDataClient` Initialization

Class ApiDataClient is the core class to work with Rest DATA. There are multiple ways to retrieve or initialize it.

// Option1. Given an astraClient
ApiDataClient client1 = astraClient.apiStargateData();
ApiDataClient client2 = astraClient.getStargateClient().apiRest();

// Option 2. Given a StargateClient
ApiDataClient client3 = stargateClient.apiRest();

// Option 3. Constructors
ApiDataClient client4_Astra    = new ApiDataClient("http://api_endpoint", "apiToken");
ApiDataClient client5_Stargate = new ApiDataClient("http://api_endpoint", 
  new TokenProviderDefault("username", "password", "http://auth_endpoint");

From now, in another samples, we will use the variable name apiClient as our working instance of ApiDataClient

Working with keyspaces

DataApiIntegrationTest is the main unit test for this API and could be use as reference code

✅. Lists available Keyspace Names

Stream<String> keyspaceNames = apiClient.keyspaceNames();

✅. Lists available Keyspaces

Stream<Keyspace> keyspaces = apiClient.keyspaces();

✅. Find a keyspace by its id

Optional<Keyspace> ns1 = apiClient.keyspace("ks1").find();

✅. Test if a keyspace exists

apiClient.keyspace("ks1").exist();

✅. Create a new keyspace

🚨 As of Today, namespaces and keyspaces creations in ASTRA are available only at the DevOps API level but work in in a StandAlone stargate deployment

// Create a keyspace with a single DC dc-1
DataCenter dc1 = new DataCenter("dc-1", 1);
apiClient.keyspace("ns1").create(dc1);

// Create a keyspace providing only the replication factor
apiClient.keyspace("ns1").createSimple(3);

✅. Delete a keyspace

🚨 As of today namespaces and keyspaces creations are not available in ASTRA but work as expected with standalone stargate.

apiClient.keyspace("ns1").delete();

ℹ️ Tips

You can simplify the code by assigning apiClient.keyspace("ks1") to a KeyspaceClient variable as shown below:

KeyspaceClient ks1Client = astraClient.apiStargateData().keyspace("ns1");
        
// Create if not exist
if (!ks1Client.exist()) {
  ks1Client.createSimple(3);
}
        
// Show datacenters where it lives
ks1Client.find().get().getDatacenters()
         .stream().map(DataCenter::getName)
         .forEach(System.out::println); 
        
// Delete 
ks1Client.delete();

Working with Tables

✅. Lists available tables in a keyspace

// We can create a local variable to shorten the code.
KeyspaceClient ks1Client = apiClient.keyspace("ks1");

// List names of the tables
Stream<String> tableNames = ks1Client.tableNames();

// List Definitions of the table (primarykey...)
Stream<TableDefinition> tableDefinitions = ks1Client.tables();

✅. Check if a table exists

TableClient tableXClient = apiClient.keyspace("ks1").table("table_x");
boolean colExist = tableXClient.exist();

✅. Retrieve a table definition from its name

Optional<TableDefinition> = apiClient.keyspace("ks1").table("table_x").find();

✅. Create a table

A TableDefinition is expected to create a table. It will detailed all columns and their specific natures (partition key and clustering columns). It can be pretty verbose as such a Builder is provided TableCreateBuilder.

// Using a builder to define the table structure
apiClient.keyspace("ks1").table("table_x").create(
  CreateTable.builder()
    .ifNotExist(true)
    .addPartitionKey("genre", "text")
    .addClusteringKey("year", "int", Ordering.DESC)
    .addClusteringKey("title", "text", Ordering.ASC)
    .addColumn("upload", "timestamp")
    .addColumn("tags", "set<text>")
    .addColumn("frames", "list<int>")
    .addColumn("tuples", "tuple<text,text,text>")
    .addColumn("formats", "frozen<map <text,text>>")
    .build()
);

✅. Update Table options

// You can change the TTL and some clustering columns informations
apiClient.keyspace("ks1").table("table_x")
         .updateOptions(new TableOptions(25, null));

✅. Delete a table

apiClient.keyspace("ks1").table("table_x").delete();

Working with Columns

✅. Lists available columns in a Table

// Get column Names
Stream<String> columnNames = apiClient.keyspace("ks1").table("table_x").columnNames();

// Get Column Definition
Stream<ColumnDefinition> columns = apiClient.keyspace("ks1").table("table_x").columns();

✅. Check if columns exists

boolean colExist = apiClient.keyspace("ks1").table("table_x").column("col1").exist();

✅. Retrieve a columns from its name

Optional<ColumnDefinition> col = apiClient
   .keyspace("ks1")
   .table("table_x")
   .column("col1")
   .find();

✅. Create an new Column

apiClient.keyspace("ks1")
         .table("table_x")
         .column("col1")
         .create(new ColumnDefinition("col", "text"));

✅. Rename a column

apiClient.keyspace("ks1")
         .table("table_x")
         .column("col1")
         .rename("col2");

✅. Delete a column

apiClient.keyspace("ks1")
         .table("table_x")
         .column("col1").delete();

Working with Indexes

✅. Lists available indexes in a Table

// Get column Names
Stream<String> indexesNames = apiClient.keyspace("ks1").table("table_x").indexesNames();

// Get Column Definition
Stream<IndexDefinition> indexes = apiClient.keyspace("ks1").table("table_x").indexes();

✅. Check if index exists

boolean colExist = apiClient.keyspace("ks1").table("table_x").index("idx1").exist();

✅. Retrieve a index from its name

Optional<IndexDefinition> idxDef = apiClient
   .keyspace("ks1")
   .table("table_x")
   .index("idx1")
   .find();

✅. Create an new Index

CreateIndex cIdx = CreateIndex.builder()
  .ifNotExist(true)
  .name("idx1").column("title")
  .sasi()
  .build();
apiClient.keyspace("ks1")
         .table("table_x")
         .index("idx1")
         .create(cIdx);

✅. Delete an Index

apiClient.keyspace("ks1")
         .table("table_x")
         .index("idx1")
         .delete();

Working with User Defined Types

✅. Lists available types in a keyspace

// We can create a local variable to shorten the code.
KeyspaceClient ks1Client = apiClient.keyspace("ks1");

// List names of the types
Stream<String> typeNames = ks1Client.typeNames();

// List Definitions of the type (attributes...)
Stream<TypeDefinition> typeDefinitions = ks1Client.types();

✅. Check if a type exists

TypeClient typeVideo = apiClient.keyspace("ks1").type("videos");
boolean colExist = typeVideo.exist();

✅. Retrieve a type definition from its name

Optional<TypeDefinition> = apiClient.keyspace("ks1").type("videos").find();

✅. Create a type

// Using a builder to define the table structure
CreateType ct = new CreateType("videos", true);
ct.getFields().add(new TypeFieldDefinition("city", "text"));
ct.getFields().add(new TypeFieldDefinition("zipcode", "int"));
ct.getFields().add(new TypeFieldDefinition("street", "text"));
ct.getFields().add(new TypeFieldDefinition("phone", "list<text>"));
apiClient.keyspace("ks1").type("videos").create(ct);

✅. Update a type

UpdateType ut= new UpdateType();
// Fields to add
ut.getAddFields().add(new TypeFieldDefinition("country","text" ));
// Fields to rename
ut.getRenameFields().add(new TypeFieldUpdate("city", "town"));
address.update(ut);

✅. Delete a type

apiClient.keyspace("ks1").type("videos").delete();

2.5. Working with Document API

Stargate and Astra bring great innovation by allowing Apache Cassandra™ to store JSON documents like a document-oriented noSQL database. The same data model is in use for each document collection leveraging a document shredding stratefy.

ApiDocumentClient Initialization

Main client object initializations (AstraClient and StargateClient) have been detailed on the Home page. Moving forward the sample code will reuse those classes but do not initialize them.

ApiDocumentClient is the core class when it comes to work with documents.

// Option1. Retrieved from astraClient
ApiDocumentClient apiDocClient1 = astraClient.apiStargateDocument();
ApiDocumentClient apiDocClient2 = astraClient.getStargateClient().apiDocument()

// Option 2. Retrieved from StargateClient
ApiDocumentClient astraClient3 = stargateClient.apiDocument();

// Option 3. Built from the endpoint and credentials
ApiDocumentClient astraClient4    = new ApiDocumentClient("http://api_endpoint", "apiToken");
ApiDocumentClient astraClient5 = new ApiDocumentClient("http://api_endpoint", 
  new TokenProviderDefault("username", "password", "http://auth_endpoint");

For the rest of the document apiDocClient will refer to ApiDocumentClient but the initialization code will not be duplicated.

Working with Namespaces

Namespace if the term used to talk about keyspaces when dealing with the document API.

DocumentApiIntegrationTest is the unit test class for this API where you can find more sample usage of the SDK.

✅. List Namespaces Names

Stream<String> namespaces = apiDocClient.namespaceNames();

✅. List Namespaces objects

Reference Api documentation

Stream<Namespace> namespaces = apiDocClient.namespaces();

The Namespace class provides the replication factor and or the datacenter list for a namespace.

public class Namespace {
    protected String name;
    protected Integer replicas;
    protected List<DataCenter> datacenters;
}

✅. Find Namespace by its name

Reference Api documentation

The parameter ns1 is here the unique identifier for the namespace

Optional<Namespace> ns1 = apiDocClient.namespace("ns1").find();

✅. Test if Namespace exists

The parameter ns1 is here the unique identifier for the namespace

apiDocClient.namespace("ns1").exist();

✅. Create Namespace

🚨 As of Today, in Astra, Namespaces and Keyspaces creations are only available at the DevOps API level or through the user interface.

// Create a namespace with a single DC dc-1
DataCenter dc1 = new DataCenter("dc-1", 1);
apiDocClient.namespace("ns1").create(dc1);

// Create a namespace providing only the replication factor
apiDocClient.namespace("ns1").createSimple(3);

✅. Delete a namespace

🚨 As of Today, in Astra, Namespaces and Keyspaces deletions are only available at the DevOps API level or through the user interface.

The parameter ns1 is here the unique identifier for the namespace.

apiDocClient.namespace("ns1").delete();

ℹ️ Fluent API

You can assign apiDocClient.namespace("ns1") to a NamespaceClient variable as shown below to simplify your code.

NamespaceClient ns1Client = astraClient.apiStargateDocument().namespace("ns1");
        
// Create if not exist
if (!ns1Client.exist())  ns1Client.createSimple(3);
        
// Show datacenters 
ns1Client.find().get()
    .getDatacenters()
    .stream()
    .map(DataCenter::getName)
    .forEach(System.out::println); 
        
// Delete 
ns1Client.delete();

Working with Collections

Reference Api documentation

Thanks to fluent API code is simplified by assigning ns1Client as NamespaceClient for ns1.

NamespaceClient ns1Client = astraClient.apiStargateDocument().namespace("ns1");

✅. List Collections in namespace

Stream<String> colNames   = ns1Client.collectionNames();

✅. Test if Collection exists

The parameter col1 is here the unique identifier for the collection in the current namespace.

boolean colExist =  = ns1Client.collection("col1").exist();

✅. Retrieve a Collection from its name

The parameter col1 is here the unique identifier for the collection in the current namespace.

Optional<CollectionDefinition> = ns1Client.collection("col1").find();

✅. Create an empty Collection

The parameter col1 is here the unique identifier for the collection in the current namespace.

ns1Client.collection("col1").create();

✅. Delete a collection

The parameter col1 is here the unique identifier for the collection in the current namespace.

ns1Client.collection("col1").delete();

ℹ️ Fluent API

Code can be simplified by assigning col1Client as CollectionClient for collection col1 in namespace ns1.

CollectionClient col1Client = astraClient.apiStargateDocument().namespace("ns1").collection("col1");

Working with Documents

📘. About Document

With Stargate document API, documents are retrieved with a Json payload and an unique identifier (UUID).

{
  "data": {
    "9e14db1c-0a05-47d2-9f27-df881f7f37ab": { "p1": "v1", "p2": "v2"},
    "9e14db1c-0a05-47d2-9f27-df881f7f37ac": { "p1": "v11", "p2": "v21"},
    "9e14db1c-0a05-47d2-9f27-df881f7f37ad": { "p1": "v12", "p2": "v22"}
  }
}

Document states as a wrapper to give access to both documentId (unique identifier) and document (payload).

public class Document<T> {
  private String documentId;
  private T document;
  // Constructor, Getters, Setters
}

📘. Paging

Due the verbose nature of the document API the maximum number of items one could retrieve from an Api call is 20 at maximum. As such, every request is paged. If the number of records is greater than the page size a field called pagingStateis provided in the response.

{
  "pagingState": "jhfekwfkwejefejwhkjewhehwrjhewjkrhewjrhewklrhewklrhewj"
  "data": {
    "9e14db1c-0a05-47d2-9f27-df881f7f37ab": { "p1": "v1", "p2": "v2"},
    "9e14db1c-0a05-47d2-9f27-df881f7f37ac": { "p1": "v11", "p2": "v21"},
    "9e14db1c-0a05-47d2-9f27-df881f7f37ad": { "p1": "v12", "p2": "v22"}
  }
}

This value pagingState has to be populated in the Query input object in order to request the next page.

// Query initialization
PageableQuery query = PageableQuery.builder().build();

// No pagingState provided = page 1
Page<Document<String>> page1 = cp.findPage(query);

// Updating the query with pagingState of page1
query.setPageState(page1.getPageState().get());

// Fetching page2
Page<Document<String>> page2 = cp.findPage(query);

🚨The following chapters propose findAll methods. Under the hood pages are fetched one after the other until exhausting the dataset. It could be slow - use it with caution.

📘. Object Mapping

Document payloads can be deserialized as beans or left unchanged as Json. To build the expected beans you can either leverage on Jackson or implement your custom DocumentMapper.

// Query initialization
PageableQuery query = PageableQuery.builder().build();

// Retrieve data as JSON, no mapper
Page<Document<String>> pageOfJsonRecords = cp.findPage(query);

// Retrieve data with default JACKSON Mapper
Page<Document<Person>> pageOfPersonRecords1 = cp.findPage(query, Person.class);

// Retrieve data with a CUSTOM Mapper
Page<Document<Person>> pageOfPersonRecords2 = cp.findPage(query, new DocumentMapper<Person>() {
  public Person map(String record) {
     return new Person();
  }
});

✅. Search Documents in a collection (with Paging)

The document Api allows to search on any fields in the document providing a where clause.

In the API where clause looks like:

{"age": {"$gte":30}, "lastname": {"$eq":"PersonAstra2"}}

This SDK provides dedicated queries and builders to help create the queries. They are of 2 kinds Query and PageableQuery.

Using the fluent API, the client collection is defined as col1Client

CollectionClient col1Client = astraClient.apiStargateDocument().namespace("ns1").collection("col1");

Build a Query and find page with no mapper

// Build pageable query
PageableQuery query = PageableQuery.builder()
  .selectAll()   // can be select("field1", "field2", ...)
  .where("firstName").isEqualsTo("John")
  .and("lastName").isEqualsTo("Connor")
  .pageSize(3)
  //.pageState() if not page 1
  .build();

// Retrieve `Page<Document<String>>` if no marshaller,  Json String are retrieved
Page<Document<String>> page1 = col1Client.findPage(query);

// Use pagingState in page1 to retrieve page2
if (page1.getPageState().isPresent()) {
  query.setPageState(page1.getPageState().get());
  Page<Document<String>> page2 = col1Client.findPage(query);
}

Retrieve Page<Document<T>> using default Jackson Mapper

Page<Document<Person>> page1 = col1Client.findPage(query, Person.class);

// Use pagingState in page1 to retrieve page2
if (page1.getPageState().isPresent()) {
  query.setPageState(page1.getPageState().get());
  Page<Document<Person>> page2 = col1Client.findPage(query, Person.class);
}

Retrieve your Page<Document<T>> using a custom mapper

public static class PersonMapper implements DocumentMapper<Person> {
  @Override
  public Person map(String record) {
    Person p = new Person();
    // custom logic
    return p;
  }    
}

Page<Document<Person>> page1 = col1Client.findPage(query, new PersonMapper());

✅. Search Documents in a collection (without Paging)
Build Query

Query query = Query.builder()
  .select("field1", "field2", ...) // to get .selectAll()
  .where("firstName").isEqualsTo("John")
  .and("lastName").isEqualsTo("Connor")
  .build();

Retrieve Stream<Document<String>>, if you do not provide any marshaller you get a Json String.

Stream<Document<String>> result = col1Client.findAll(query);

Retrieve your Stream<Document<T>> using default Jackson Mapper

Stream<Document<Person>> res1 = col1Client.findAll(query, Person.class);

Retrieve your Stream<Document<T>> using your custom mapping

public static class PersonMapper implements DocumentMapper<Person> {
  @Override
  public Person map(String record) {
    Person p = new Person();
    // custom logic
    return p;
  }    
}

Stream<Document<Person>> page1 = col1Client.findAll(query, new PersonMapper());

Retrieving all collection documents is possible, it is the default query.

// Get all documents
Stream<Document<String>> allDocs1 = col1Client.findAll();

// Equivalent to 
Stream<Document<String>> allDocs2 = ccol1Clientp.findAll(Query.builder().build());

// Also available
Stream<Document<Person>> allDocs3 = col1Client.findAll(Person.class);
Stream<Document<Person>> allDocs4 = col1Client.findAll(new DocumentMapper());

✅. Get a Document by its identifier

// doc1 is the document Id in the collection
boolean docExist = col1Client.document("doc1").exist();

// Find if it exists (no mapper)
Optional<String> p = col1Client.document("doc1").find();
// Find if it exists (default mapper)
Optional<Person> p = col1Client.document("doc1").find(Person.class);
// Find if it exists (custom mapper)
Optional<Person> p = col1Client.document("doc1").find(new DocumentMapper<Person>() { ...});

✅. Create a new document (without providing identifier)

The method createNewDocument in CollectionClient will create a document generating the unique identifier as a UUID. (this is how the underlying api works).

// Define an object
Person john = new Person("John", "Doe", 20, new Address("Paris", 75000));

// As no id has been provided, the API will create a UUID and returned it to you 
String docId = col1Client.createNewDocument(john);

✅. Create/update document by providing identifier

// Define an object
Person john2 = new Person("John", "Doe", 20, new Address("Paris", 75000));

// Now the id is provided (myId) and we can upsert
String docId = col1Client.document("myId").upsert(john2, Person.class);

✅. Delete a document from its identifier

col1Client.document("myId").delete();

✅. Count documents in a collection

🚨 This operation can be slow as it leverage on findAll minimizing the payloads

int docNum = col1Client.count();

✅. Find part of a document

The document API allows to work with nested structure in a document. {document-path} (subpath) is required at the URL level

http://{doc-api-endpoint}/namespaces/{namespace-id}/collections/{collection-id}/{document-id}/{document-path}

Given a Json DOCUMENT with UUID e8c5021b-2c91-4015-aec6-14a16e449818 :

{ 
  "age": 25,
  "firstname": "PersonAstra5",
  "lastname": "PersonAstra1",
  "address": {
    "city": "Paris",
    "zipCode": 75000
   },
}

You can retrieve the zipCode with: http://{doc-api-endpoint}/namespaces/ns1/collections/person/e8c5021b-2c91-4015-aec6-14a16e449818/address/zipCode

The SDK provides some utility methods to work with :

// Retrieve an object and marshall
Optional<Address> address = col1Client
   .document("e8c5021b-2c91-4015-aec6-14a16e449818")
   .findSubDocument("address", Address.class);
        
// Retrieve a scalar deeper in the tree
Optional<Integer> zipcode = col1Client
  .document("e8c5021b-2c91-4015-aec6-14a16e449818")
  .findSubDocument("address/zipCode", Integer.class);

✅. Update a sub document

// Update an existing attribute of the JSON
col1Client.document("e8c5021b-2c91-4015-aec6-14a16e449818")
               .updateSubDocument("address", new Address("city2", 8000));

// Create a new attribute in the document
col1Client.document("e8c5021b-2c91-4015-aec6-14a16e449818")
               .updateSubDocument("secondAddress", new Address("city2", 8000));

✅. Delete part of a documents

col1Client.document("e8c5021b-2c91-4015-aec6-14a16e449818")
               .deleteSubDocument("secondAddress");

Document Repository

📘. StargateDocumentRepository overview

If you have work with Spring Data or Active Record before you might already know what the repository are. Those are classes that provides you CRUD (create, read, update, delete) operations without you having to code anything.

Here this is not different, if you provide an object for a collection this is what is available for you

public interface StargateDocumentRepository <DOC> {
   
   // Create
   String insert(DOC p);
   void insert(String docId, DOC doc);
   
   // Read unitary
   boolean exists(String docId);
   Optional<DOC> find(String docId);

   // Read records
   int count();
   DocumentResultPage<DOC> findPage();
   DocumentResultPage<DOC> findPage(SearchDocumentQuery query) ;
   Stream<ApiDocument<DOC>> findAll();
   Stream<ApiDocument<DOC>> findAll(SearchDocumentQuery query);

  // Update
  void save(String docId, DOC doc);

  // Delete
  void delete(String docId);
}

✅. Initialization of repository

// Initialization (from namespaceClients)
NamespaceClient ns1Client = astraClient.apiStargateDocument().namespace("ns1");
StargateDocumentRepository<Person> personRepository1 = 
  new StargateDocumentRepository<Person>(ns1Client, Person.class);

Points to note:

No collection name is provided here. By default the SDK will use the class name in lower case (here person)
If you want to override the collection name you can annotate your bean Person with @Collection("my_collection_name")

// Initialization from CollectionClient, no ambiguity on collection name
CollectionClient colPersonClient = astraClient.apiStargateDocument()
 .namespace("ns1").collection("person");
StargateDocumentRepository<Person> personRepository2 = 
  new StargateDocumentRepository<Person>(colPersonClient, Person.class);

✅. CRUD

We assume that the repository has been initialized as describe above and name personRepo.

if (!personRepo.exists("Cedrick")) {
  personRepo.save("Cedrick", new Person("Cedrick", "Lunven", new Address()));
}

// Yeah
personRepository.findAll()                     // Stream<ApiDocument<Person>>      
                .map(ApiDocument::getDocument) // Stream<Person>      
                .map(PersonRepo::getFirstname) // Stream<String>
                .forEach(System.out::println);

clun/stargate-sdk-java

Stargate Software Development Kit

Table of Contents

1. Introducing Stargate

1.1 Overview

1.2 Api Descriptions

2. Stargate SDK

2.1 Prerequisites

📦 Docker

📦 Java Development Kit (JDK) 8+

📦 Apache Maven

2.2 Start Stargate

2.3. Quickstart

✅ Initialize Stargate client

✅ Execute the main class `QuickstartStargate.java`

✅ Check you can invoke each Api. Add the following utilities methods in `QuickstartStargate.java`

✅ Update the `main` method accordingly:

✅ Execute the main class `QuickstartStargate.java` again

2.4. Working with Rest API

`ApiDataClient` Initialization

Working with keyspaces

Working with Tables

Working with Columns

Working with Indexes

Working with User Defined Types

2.5. Working with Document API

ApiDocumentClient Initialization

Working with Namespaces

Working with Collections

Working with Documents

📘. Object Mapping

Document Repository

2.6. Working with GRPC API

2.7. Working with Graph QL

2.8. Working with Json API

clun/stargate-sdk-java

Stargate Software Development Kit

Table of Contents

1. Introducing Stargate

1.1 Overview

1.2 Api Descriptions

2. Stargate SDK

2.1 Prerequisites

📦 Docker

📦 Java Development Kit (JDK) 8+

📦 Apache Maven

2.2 Start Stargate

2.3. Quickstart

✅ Initialize Stargate client

✅ Execute the main class QuickstartStargate.java

✅ Check you can invoke each Api. Add the following utilities methods in QuickstartStargate.java

✅ Update the main method accordingly:

✅ Execute the main class QuickstartStargate.java again

2.4. Working with Rest API

ApiDataClient Initialization

Working with keyspaces

Working with Tables

Working with Columns

Working with Indexes

Working with User Defined Types

2.5. Working with Document API

ApiDocumentClient Initialization

Working with Namespaces

Working with Collections

Working with Documents

📘. Object Mapping

Document Repository

2.6. Working with GRPC API

2.7. Working with Graph QL

2.8. Working with Json API

✅ Execute the main class `QuickstartStargate.java`

✅ Check you can invoke each Api. Add the following utilities methods in `QuickstartStargate.java`

✅ Update the `main` method accordingly:

✅ Execute the main class `QuickstartStargate.java` again

`ApiDataClient` Initialization