Convenience methods for creating advance nonce instruction. Document how to create a durable transaction.

Author: jpe7s

README.md

@@ -62,9 +62,8 @@ request.
 ```
 final Signer signer = ...
  
-final var rpcEndpoint = URI.create("https://mainnet.helius-rpc.com/?api-key=");
 try (final var httpClient = HttpClient.newHttpClient()) {
-  final var rpcClient = SolanaRpcClient.createClient(rpcEndpoint, httpClient);
+  final var rpcClient = SolanaRpcClient.createClient(SolanaNetwork.MAIN_NET.getEndpoint(), httpClient);
 
   final var blockHashFuture = rpcClient.getLatestBlockHash();
   final var minRentFuture = rpcClient.getMinimumBalanceForRentExemption(NonceAccount.BYTES);
@@ -133,3 +132,48 @@ try (final var httpClient = HttpClient.newHttpClient()) {
   System.out.println(nonceAccount);
 }
 ```
+
+### Create & Send Durable Transaction
+
+```
+final var signer = ...
+final var nonceAccountKey = PublicKey.fromBase58Encoded("");
+final var sendToKey = PublicKey.fromBase58Encoded("");
+final var transferSOL = new BigDecimal("0.0");
+
+final var solanaAccounts = SolanaAccounts.MAIN_NET;
+try (final var httpClient = HttpClient.newHttpClient()) {
+  final var rpcClient = SolanaRpcClient.createClient(SolanaNetwork.MAIN_NET.getEndpoint(), httpClient);
+
+  final var nonceAccountInfo = rpcClient.getAccountInfo(nonceAccountKey).join();
+  final var nonceAccount = NonceAccount.read(nonceAccountInfo);
+  System.out.println(nonceAccount);
+
+  final var advanceNonceIx = nonceAccount.advanceNonceAccount(solanaAccounts);
+  final var transferIx = SystemProgram.transfer(
+      solanaAccounts.invokedSystemProgram(),
+      signer.publicKey(),
+      sendToKey,
+      LamportDecimal.fromBigDecimal(transferSOL).longValue()
+  );
+
+  final var instructions = List.of(advanceNonceIx, transferIx);
+  final var transaction = Transaction.createTx(signer.publicKey(), instructions);
+  transaction.setRecentBlockHash(nonceAccount.nonce());
+  transaction.sign(signer);
+
+  final var base64Encoded = transaction.base64EncodeToString();
+  final var sendTransactionFuture = rpcClient.sendTransaction(base64Encoded);
+  System.out.format("""
+          Transferring %s SOL from %s to %s.
+          https://explorer.solana.com/tx/%s
+          
+          """,
+      transferSOL.toPlainString(), signer.publicKey(), sendToKey,
+      transaction.getBase58Id()
+  );
+
+  final var sig = sendTransactionFuture.join();
+  System.out.println("Confirmed transaction " + sig);
+}
+```

src/main/java/software/sava/solana/programs/system/NonceAccount.java

@@ -1,8 +1,10 @@
 package software.sava.solana.programs.system;
 
 import software.sava.core.accounts.PublicKey;
+import software.sava.core.accounts.SolanaAccounts;
 import software.sava.core.encoding.ByteUtil;
 import software.sava.core.rpc.Filter;
+import software.sava.core.tx.Instruction;
 import software.sava.core.tx.Transaction;
 import software.sava.rpc.json.http.response.AccountInfo;
 import software.sava.solana.programs.stake.StakeState;
@@ -96,4 +98,22 @@ public static NonceAccount read(final PublicKey address, final byte[] data, int
         lamportsPerSignature
     );
   }
+
+  public Instruction advanceNonceAccount() {
+    return advanceNonceAccount(SolanaAccounts.MAIN_NET);
+  }
+
+  public Instruction advanceNonceAccount(final SolanaAccounts solanaAccounts) {
+    return SystemProgram.advanceNonceAccount(solanaAccounts, address, authority);
+  }
+
+  public void setNonce(final Transaction transaction) {
+    setNonce(SolanaAccounts.MAIN_NET, transaction);
+  }
+
+  public void setNonce(final SolanaAccounts solanaAccounts, final Transaction transaction) {
+    transaction.setRecentBlockHash(nonce);
+    final var advanceNonceIx = advanceNonceAccount(solanaAccounts);
+    transaction.prependIx(advanceNonceIx);
+  }
 }