dfinity-agent

Java Candid for The Internet Computer (IC4J) is a collection of open-source native Java libraries designed to handle Candid types on the Internet Computer. Full documentation here

https://dfinity.org/

The code is implementation of the Internet Computer Interface protocol

https://sdk.dfinity.org/docs/interface-spec/index.html

and it's using Dfinity Rust agent as an inspiration, using similar package structures and naming conventions.

https://github.com/dfinity/agent-rs

License

IC4J Candid is available under Apache License 2.0.

Documentation

Supported type mapping between Java and Candid

POJO Java class with Candid annotations

import java.math.BigInteger;

import org.ic4j.candid.annotations.Field;
import org.ic4j.candid.annotations.Name;
import org.ic4j.candid.types.Type;

public class Pojo {
    @Field(Type.BOOL)
    @Name("bar")
    public Boolean bar;

    @Field(Type.INT)
    @Name("foo")
    public BigInteger foo;
}

Pojo pojoValue = new Pojo();

pojoValue.bar = new Boolean(false);
pojoValue.foo = BigInteger.valueOf(43); 

JSON (Jackson) serialization and deserialization

Use JacksonSerializer to serialize Jackson JsonNode or Jackson compatible Pojo class to Candid

JsonNode jsonValue;
IDLType idlType;

IDLValue idlValue = IDLValue.create(jsonValue, JacksonSerializer.create(idlType));
List<IDLValue> args = new ArrayList<IDLValue>();
args.add(idlValue);

IDLArgs idlArgs = IDLArgs.create(args);

byte[] buf = idlArgs.toBytes();

Use JacksonDeserializer to deserialize Candid to Jackson JsonNode or Jackson compatible Pojo class

JsonNode jsonResult = IDLArgs.fromBytes(buf).getArgs().get(0)
    .getValue(JacksonDeserializer.create(idlValue.getIDLType()), JsonNode.class);

XML (DOM) serialization and deserialization

Use DOMSerializer to serialize DOM Node to Candid

Node domValue;

IDLValue idlValue = IDLValue.create(domValue,DOMSerializer.create());
List<IDLValue> args = new ArrayList<IDLValue>();
args.add(idlValue);

IDLArgs idlArgs = IDLArgs.create(args);

byte[] buf = idlArgs.toBytes();

Use DOMDeserializer to deserialize Candid to DOM Node

DOMDeserializer domDeserializer = DOMDeserializer.create(idlValue.getIDLType()).rootElement("http://scaleton.com/dfinity/candid","data");

Node domResult = IDLArgs.fromBytes(buf).getArgs().get(0).getValue(domDeserializer, Node.class);

JDBC (ResultSet) serialization

Use JDBCSerializer to serialize JDBC ResultSet to Candid

ResultSet result = statement.executeQuery(sql);

IDLValue idlValue = IDLValue.create(result, JDBCSerializer.create());
List<IDLValue> args = new ArrayList<IDLValue>();
args.add(idlValue);

IDLArgs idlArgs = IDLArgs.create(args);

byte[] buf = idlArgs.toBytes();

Downloads / Accessing Binaries

To add Java IC4J Candid library to your Java project use Maven or Gradle import from Maven Central.

https://search.maven.org/artifact/ic4j/ic4j-candid/0.7.4/jar

<dependency>
  <groupId>org.ic4j</groupId>
  <artifactId>ic4j-candid</artifactId>
  <version>0.7.4</version>
</dependency>

implementation 'org.ic4j:ic4j-candid:0.7.4'

Dependencies

This this is using these open source libraries

Jackson JSON Serializer and Deserializer

To manage Jackson objects.

Java CC

To parse IC IDL Candid files

Build

You need JDK 8+ to build IC4J Candid.