feat(HIP-745): Optionally send transaction data without required tran…

…saction fields (#1739)

Signed-off-by: Nikita Lebedev <[email protected]>

examples/src/main/java/TransactionSerializationExample.java

@@ -0,0 +1,81 @@
+import com.hedera.hashgraph.sdk.AccountBalanceQuery;
+import com.hedera.hashgraph.sdk.AccountId;
+import com.hedera.hashgraph.sdk.Client;
+import com.hedera.hashgraph.sdk.Hbar;
+import com.hedera.hashgraph.sdk.PrivateKey;
+import com.hedera.hashgraph.sdk.Transaction;
+import com.hedera.hashgraph.sdk.TransactionRecord;
+import com.hedera.hashgraph.sdk.TransferTransaction;
+import io.github.cdimascio.dotenv.Dotenv;
+import java.util.Objects;
+
+public class TransactionSerializationExample {
+
+    // see `.env.sample` in the repository root for how to specify these values
+    // or set environment variables with the same names
+    private static final AccountId OPERATOR_ID = AccountId.fromString(Objects.requireNonNull(Dotenv.load().get("OPERATOR_ID")));
+    private static final PrivateKey OPERATOR_KEY = PrivateKey.fromString(Objects.requireNonNull(Dotenv.load().get("OPERATOR_KEY")));
+    // HEDERA_NETWORK defaults to testnet if not specified in dotenv
+    private static final String HEDERA_NETWORK = Dotenv.load().get("HEDERA_NETWORK", "testnet");
+
+    public TransactionSerializationExample() {
+    }
+
+    public static void main(String[] args) throws Exception {
+        Client client = ClientHelper.forName(HEDERA_NETWORK);
+
+        // Defaults the operator account ID and key such that all generated transactions will be paid for
+        // by this account and be signed by this key
+        client.setOperator(OPERATOR_ID, OPERATOR_KEY);
+
+        AccountId recipientId = AccountId.fromString("0.0.3");
+        Hbar amount = Hbar.fromTinybars(10_000);
+
+        Hbar senderBalanceBefore = new AccountBalanceQuery()
+            .setAccountId(OPERATOR_ID)
+            .execute(client)
+            .hbars;
+
+        Hbar receiptBalanceBefore = new AccountBalanceQuery()
+            .setAccountId(recipientId)
+            .execute(client)
+            .hbars;
+
+        System.out.println("" + OPERATOR_ID + " balance = " + senderBalanceBefore);
+        System.out.println("" + recipientId + " balance = " + receiptBalanceBefore);
+
+        var transferTransaction = new TransferTransaction()
+            // .addSender and .addRecipient can be called as many times as you want as long as the total sum from
+            // both sides is equivalent
+            .addHbarTransfer(OPERATOR_ID, amount.negated());
+
+        var transactionBytes = transferTransaction.toBytes();
+
+        TransferTransaction transferTransactionDeserialized = (TransferTransaction) Transaction.fromBytes(transactionBytes);
+
+        var transactionResponse = transferTransactionDeserialized
+            .addHbarTransfer(recipientId, amount)
+            .setTransactionMemo("transfer test")
+            .execute(client);
+
+        System.out.println("transaction ID: " + transactionResponse);
+
+        TransactionRecord record = transactionResponse.getRecord(client);
+
+        System.out.println("transferred " + amount + "...");
+
+        Hbar senderBalanceAfter = new AccountBalanceQuery()
+            .setAccountId(OPERATOR_ID)
+            .execute(client)
+            .hbars;
+
+        Hbar receiptBalanceAfter = new AccountBalanceQuery()
+            .setAccountId(recipientId)
+            .execute(client)
+            .hbars;
+
+        System.out.println("" + OPERATOR_ID + " balance = " + senderBalanceAfter);
+        System.out.println("" + recipientId + " balance = " + receiptBalanceAfter);
+        System.out.println("Transfer memo: " + record.transactionMemo);
+    }
+}