Refactor Send XRP: reliable sub, folders by language

- Use reliable transaction submission methods where available
- Update text to describe the functions (esp. xrpl.js 2.0 stuff)
- Move Send XRP code samples to subfolders by language for consistency
  with other tutorials

content/_code-samples/send-xrp/java/SendXrp.java

@@ -0,0 +1,120 @@
+// Example Credentials --------------------------------------------------------
+WalletFactory walletFactory = DefaultWalletFactory.getInstance();
+Wallet testWallet = walletFactory
+  .fromSeed("sn3nxiW7v8KXzPzAqzyHXbSSKNuN9", true)
+  .wallet();
+
+// Get the Classic address from testWallet
+Address classicAddress = testWallet.classicAddress();
+System.out.println(classicAddress); // "rMCcNuTcajgw7YTgBy1sys3b89QqjUrMpH"
+
+// Connect --------------------------------------------------------------------
+HttpUrl rippledUrl = HttpUrl.get("https://s.altnet.rippletest.net:51234/");
+XrplClient xrplClient = new XrplClient(rippledUrl);
+
+// Prepare transaction --------------------------------------------------------
+// Look up your Account Info
+AccountInfoRequestParams requestParams = AccountInfoRequestParams.builder()
+  .ledgerIndex(LedgerIndex.VALIDATED)
+  .account(classicAddress)
+  .build();
+AccountInfoResult accountInfoResult = xrplClient.accountInfo(requestParams);
+UnsignedInteger sequence = accountInfoResult.accountData().sequence();
+
+// Request current fee information from rippled
+FeeResult feeResult = xrplClient.fee();
+XrpCurrencyAmount openLedgerFee = feeResult.drops().openLedgerFee();
+
+// Get the latest validated ledger index
+LedgerIndex validatedLedger = xrplClient.ledger(
+    LedgerRequestParams.builder()
+      .ledgerIndex(LedgerIndex.VALIDATED)
+      .build()
+  )
+  .ledgerIndex()
+  .orElseThrow(() -> new RuntimeException("LedgerIndex not available."));
+
+// Workaround for https://github.com/XRPLF/xrpl4j/issues/84
+UnsignedInteger lastLedgerSequence = UnsignedInteger.valueOf(
+  validatedLedger.plus(UnsignedLong.valueOf(4)).unsignedLongValue().intValue()
+);
+
+// Construct a Payment
+Payment payment = Payment.builder()
+  .account(classicAddress)
+  .amount(XrpCurrencyAmount.ofXrp(BigDecimal.ONE))
+  .destination(Address.of("rPT1Sjq2YGrBMTttX4GZHjKu9dyfzbpAYe"))
+  .sequence(sequence)
+  .fee(openLedgerFee)
+  .signingPublicKey(testWallet.publicKey())
+  .lastLedgerSequence(lastLedgerSequence)
+  .build();
+System.out.println("Constructed Payment: " + payment);
+
+// Sign transaction -----------------------------------------------------------
+// Construct a SignatureService to sign the Payment
+PrivateKey privateKey = PrivateKey.fromBase16EncodedPrivateKey(
+  testWallet.privateKey().get()
+);
+SignatureService signatureService = new SingleKeySignatureService(privateKey);
+
+// Sign the Payment
+SignedTransaction<Payment> signedPayment = signatureService.sign(
+  KeyMetadata.EMPTY,
+  payment
+);
+System.out.println("Signed Payment: " + signedPayment.signedTransaction());
+
+// Submit transaction ---------------------------------------------------------
+SubmitResult<Transaction> prelimResult = xrplClient.submit(signedPayment);
+System.out.println(prelimResult);
+
+// Wait for validation --------------------------------------------------------
+boolean transactionValidated = false;
+boolean transactionExpired = false;
+while (!transactionValidated && !transactionExpired) {
+  Thread.sleep(4 * 1000);
+  LedgerIndex latestValidatedLedgerIndex = xrplClient.ledger(
+      LedgerRequestParams.builder().ledgerIndex(LedgerIndex.VALIDATED).build()
+    )
+    .ledgerIndex()
+    .orElseThrow(() ->
+      new RuntimeException("Ledger response did not contain a LedgerIndex.")
+    );
+
+  TransactionResult<Payment> transactionResult = xrplClient.transaction(
+    TransactionRequestParams.of(signedPayment.hash()),
+    Payment.class
+  );
+
+  if (transactionResult.validated()) {
+    System.out.println("Payment was validated with result code " +
+      transactionResult.metadata().get().transactionResult());
+    transactionValidated = true;
+  } else {
+    boolean lastLedgerSequenceHasPassed = FluentCompareTo.
+      is(latestValidatedLedgerIndex.unsignedLongValue())
+      .greaterThan(UnsignedLong.valueOf(lastLedgerSequence.intValue()));
+    if (lastLedgerSequenceHasPassed) {
+      System.out.println("LastLedgerSequence has passed. Last tx response: "
+        transactionResult);
+    );
+      transactionExpired = true;
+    } else {
+      System.out.println("Payment not yet validated.");
+    }
+  }
+}
+
+// Check transaction results --------------------------------------------------
+System.out.println(transactionResult);
+System.out.println("Explorer link: https://testnet.xrpl.org/transactions/" +
+    signedPayment.hash());
+transactionResult.metadata().ifPresent(metadata -> {
+  System.out.println("Result code: " + metadata.transactionResult());
+
+  metadata.deliveredAmount().ifPresent(deliveredAmount ->
+    System.out.println("XRP Delivered: " +
+      ((XrpCurrencyAmount) deliveredAmount).toXrp())
+  );
+});