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Wallet

This API provides convinience mathods to interact with the NKN Wallet, which is a combination of private and public keys. It provides functionality to create, store, load ans transact with the wallet.

Create Wallet#

The wallet can be created in multiple ways.

Create a new wallet#

Create a new wallet from a new seed. This method will create a new seed and create a new private/public key pair.

Wallet wallet = Wallet.createNew();

Create from existing seed#

Create a wallet object from an existing seed. The seed can be provided either in hex format for string format.

Wallet wallet = Wallet.createFromSeed("697f3a8d50dbcede9c39730ed90e5a8109a56153b6b7fdc18d475aedc048ef44");
caution

Never share the seed with anyone and keep it safe. This secret seed can be used to retrieve your wallet.

Save Wallet#

The wallet information can be stored on a file either local or on network.

Local File#

The save method creates a password protected local file and stores the keys.

Wallet wallet = Wallet.createNew();try {    wallet.save(new File("wallet.json"), "secretPassword");} catch (WalletException exp){    System.out.println("Exception while saving wallet information: " + exp.getMessage());}

Output Stream#

The save method also accepts and OutputStream object to send the wallet informtion across the network. 

Wallet wallet = Wallet.createNew();try {    FileOutputStream outputStream = new FileOutputStream(new File("wallet.json"));    wallet.save(outputStream, "secretPassword");} catch (Exception exp){    System.out.println("Exception while saving wallet information: " + exp.getMessage());}
tip

Replace the FileOutputStream with any other output stream to write the information across network.

Load Wallet#

Converse to saving, the wallet can be loaded from the local file system or any other input stream.

Local File#

Load the existing wallet from a local file by providing the file object corresponding to local file and the password used while saving it.

try {    Wallet wallet = Wallet.load(new File("wallet.json"), "secretPassword");    System.out.println(wallet.getAddress());} catch (WalletException e) {    System.out.println("Exception while restoring wallet from the wallet file");}

Input Stream#

Similar to its save counterpart, the load method also accepts an input stream to load the wallet from anywhere as long as the stream is valid.

try {    FileInputStream fileInputStream = new FileInputStream(new File("wallet.json"));    Wallet wallet = Wallet.load(fileInputStream, "secretPassword");    System.out.println(wallet.getAddress());} catch (Exception e) {    System.out.println("Exception while restoring wallet from the wallet file");}

Transactions#

Create Transaction#

Wallet API provides an instance of NKNTransaction wrapped around the wallet address. This NKNTransaction instance can be used to execute business transactions.

Wallet wallet = Wallet.createNew();NKNTransaction nknTransaction = wallet.tx();
info

The following predefined transactions are possible using the NKNTransaction object:

  • deleteName
  • registerName
  • subscribe
  • transferTo
  • unsubscribe

In case the requirement does not fit into these predefined transactions, the user can also use customTransaction method to submit a transaction customized for his own needs.

Get Balancce#

Users can query the wallet for its balance.

Wallet wallet = Wallet.createNew();try {    System.out.println(wallet.queryBalance());} catch (NKNExplorerException e) {    e.printStackTrace();}
note

The wallet is dependent on the NKN Explorer to get it's balance. More about this in the Explorer section.

Metadata#

Wallet also provides methods to access the its metadata

Address#

Get the NKN address associated with the wallet

Wallet wallet = Wallet.createNew();System.out.println(wallet.getAddress());

Public Key#

Get the public key associted with the wallet.

import org.bouncycastle.util.encoders.Hex;
Wallet wallet = Wallet.createNew();System.out.println(Hex.toHexString(wallet.getPublicKey()));

Program Hash#

Get the program hash from the public key of the wallet.

import org.bouncycastle.util.encoders.Hex;
Wallet wallet = Wallet.createNew();System.out.println(Hex.toHexString(wallet.getProgramHash().toByteArray()));

Contract Data#

Get stringified contract data

Wallet wallet = Wallet.createNew();System.out.println(wallet.getContractDataAsString());