MultiChainJavaAPI

MultiChainJAVAAPI is an open source Java interface MultiChain blockchains, written in Java.

https://github.com/SimplyUb/MultiChainJavaAPI

Copyright (c) 2017 Worldline
License: GNU General Public License version 3, see COPYING

System requirements

These compilation instructions have been tested on Windows 7.0 and Ubuntu 12.4 x64 only with Java 1.7.0_80 with Multichain 2.0 beta 2.

Dependencies

* Multichain 2.0 beta 2
* Java 1.7.0 is needed, upper version should be compatible.
* All other dependencies are managed by Maven.

Installation

	.\install.sh

or manually :

	mvn clean install

will create 2 jar files in local repository :

• version : light version
• version : full directly included all dependencies

Architecture

Global Architecture

The goal of the API is to directly integrate calls to command system and Json Formating to make Java development easier :

The initial mind of the project is to manage Wallet. There's no command to manage the BlockChain like : create a blockChain, join a blockChain, ... Theses commands are more linked with the system. Next versions will decide to integrate (or not) theses commands.

Project Architecture

multichain.command and CommandManager

The package multichain.command and the Class CommandManager are the essentials of the project. They contain Java the command to call.

public Object invoke(CommandElt command, Object... parameters) throws MultichainException

• command : Multichain command to call
• parameters : (optional) list of parameters joined to the command

Examples of command calls can be found in test/multichain.command.CommandManagerTest.

A simple example to get addresses :

//BlockChain has to be created and started before
CommandManager commandManager= new CommandManager("localhost", "6824", "multichainrpc","73oYQWzx45hossFPPWUgicpLvHhsD8PempYxnSF6bnY9");

// localhost is the IP used by Multichain
// 6824 is, here, the port used by the BlockChain, corresponding of the value of default-rpc-port in the file params.dat 
// multichainrpc and 73oYQWzx45h... are login and password to access to RPC commands, values can be found in the file multichain.conf

Object addressResult = null;

try {
  addressResult = commandManager.invoke(CommandElt.GETADDRESSES);
} catch (MultichainException e) {
  e.printStackTrace();
  fail();
}

//result contains the addresses of the wallet as list of String (verbose is false).
//class java.util.ArrayList
//class java.lang.String

try {
  addressResult = commandManager.invoke(CommandElt.GETADDRESSES, true);
} catch (MultichainException e) {
  e.printStackTrace();
  fail();
}

//result contains the addresses of the wallet as list of Addresses (verbose is true).
//class java.util.ArrayList
//class multichain.object.Address

multichain.command.CommandElt

This Enum contains command definitions, for example :

GETADDRESSES("getaddresses", null, new Class<?>[] {String.class, Address.class}, true),

element name	GETADDRESSES
multichain command	"getaddresses" : call this multichain command
input parameters	null : #TODO#
output parameters	new Class<?>[] {String.class, Address.class} : output can be either String or Address
output list flag	true : output will follow list format

multichain.object.formatters.GenericOutputFormatter is the only formatter and is based on the output defined in this Enum. To format Json to Java, it's using Gson API.

multichain.object

The package multichain.object contains Java objects which can be used to call functions (in queryobjects) or returned by functions.

a few examples

String message = (String) commandManager.invoke(CommandElt.GETNEWADDRESS);

List<Permission> listPermissions = (List<Permission>) commandManager.invoke(CommandElt.LISTPERMISSIONS);

String message = (String) commandManager.invoke(CommandElt.GRANT, addressString, GrantElt.grantElements(permissions));

AssetParams params = new AssetParams(name, true);
String message = (String) commandManager.invoke(CommandElt.ISSUEFROM, fromAddressString, toAddressString, params, quantity, 1);

MultiBalance balance = (MultiBalance)commandManager.invoke(CommandElt.GETMULTIBALANCES);

List<BalanceAssetGeneral> balance = (List<BalanceAssetGeneral>)commandManager.invoke(CommandElt.GETADDRESSBALANCES, AddressString);

Map<String, Double> basket = new HashMap();
basket.put(assetName1, assetQty1);
basket.put(assetName2, assetQty2);
String message = (String)commandManager.invoke(CommandElt.SENDFROM, fromAddressString, toAddressString, basket);
String message = (String)commandManager.invoke(CommandElt.SENDWITHDATAFROM, fromAddressString, toAddressString, basket, metadata);

Versions

2.0.1

• All new version :-)
• Only one calling command : invoke

1.3.0

• Direct RPC Server calls
• Dependencies under Maven

1.2.0

Based on functions contained in MultiChain 1.0 Beta 1

Integrated functions about :

• Streams

1.1.0

Based on functions contained in MultiChain Alpha 24

Integrated functions about :

• Block
• Address
• Grant
• Balance
• Wallet
• Issue/Assets
• Transaction
• Transaction RAW

License

MultiChainJAVAAPI is released under the [GNU General Public License version 3] (LICENSE).

Copyright (c) 2017 Worldline.

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.