30: Submit signed transactions through the Solana API

src/main/tjava/com/r35157/libs/solana/SolanaBlockChain.tjava

@@ -10,7 +10,7 @@ import java.util.Map;
 import java.util.Set;
 
 /**
- * Provides read-oriented access to the Solana blockchain.
+ * Provides generic access to the Solana blockchain.
  *
  * <p>This interface exposes the Solana operations needed by higher-level
  * integrations. It can fetch native SOL balances, SPL token holdings, NFT-like
@@ -164,4 +164,22 @@ public interface SolanaBlockChain {
             ΩSolanaProgramIdΩ programId,
             Set<SolanaProgramAccountMemcmpFilter> filters
     ) throws IOException, InterruptedException;
+
+    /**
+     * Submits a complete signed transaction to the Solana blockchain.
+     *
+     * <p>The transaction must already contain all required signatures.
+     * This method does not sign or modify the transaction.</p>
+     *
+     * @param transaction the complete signed transaction to submit
+     * @return the transaction signature returned by Solana RPC
+     * @throws IllegalArgumentException if the serialized transaction is blank
+     * @throws IOException if the transaction cannot be submitted or Solana
+     *                     returns an RPC error
+     * @throws InterruptedException if the calling thread is interrupted while
+     *                              submitting the transaction
+     */
+    ΩSolanaTransactionSignatureΩ sendTransaction(
+            SolanaSignedTransaction transaction
+    ) throws IOException, InterruptedException;
 }

src/main/tjava/com/r35157/libs/solana/SolanaSignedTransaction.tjava

@@ -0,0 +1,11 @@
+package com.r35157.libs.solana;
+
+/**
+ * A complete serialized Solana transaction containing all required signatures.
+ *
+ * @param serializedTransaction the signed transaction encoded as Base64
+ */
+public record SolanaSignedTransaction(
+        ΩBase64StringΩ serializedTransaction
+) {
+}

src/main/tjava/com/r35157/libs/solana/impl/cached/CachedSolanaBlockChain.tjava

@@ -8,6 +8,7 @@ import com.r35157.libs.solana.SolanaAccountInfo;
 import com.r35157.libs.solana.SolanaBlockChain;
 import com.r35157.libs.solana.SolanaProgramAccountMemcmpFilter;
 import com.r35157.libs.solana.SolanaProgramAddressSeed;
+import com.r35157.libs.solana.SolanaSignedTransaction;
 import com.r35157.libs.solana.valuetypes.SolanaProgramDerivedAddress;
 import com.r35157.libs.solana.valuetypes.economic.SolanaSPLTokenProgram;
 import com.r35157.libs.valuetypes.basic.MoneyAmount;
@@ -163,6 +164,13 @@ public final class CachedSolanaBlockChain implements SolanaBlockChain {
         return result;
     }
 
+    @Override
+    public ΩSolanaTransactionSignatureΩ sendTransaction(
+            SolanaSignedTransaction transaction
+    ) throws IOException, InterruptedException {
+        return delegate.sendTransaction(transaction);
+    }
+
     private synchronized Set<SolanaAccountInfo> loadProgramAccounts(
             ObjectCacheKey key,
             ΩSolanaProgramIdΩ programId,

src/main/tjava/com/r35157/libs/solana/impl/ref/SolanaBlockChainImpl.tjava

@@ -2,12 +2,14 @@ package com.r35157.libs.solana.impl.ref;
 
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.node.ArrayNode;
+import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.r35157.libs.solana.*;
 import com.r35157.libs.solana.valuetypes.SolanaProgramDerivedAddress;
-import com.r35157.libs.valuetypes.basic.MoneyAmount;
-import com.r35157.libs.valuetypes.basic.WellKnownCurrencyTypes;
 import com.r35157.libs.solana.valuetypes.economic.SolanaSPLTokenProgram;
 import com.r35157.libs.valuetypes.basic.CurrencyType;
+import com.r35157.libs.valuetypes.basic.MoneyAmount;
+import com.r35157.libs.valuetypes.basic.WellKnownCurrencyTypes;
 
 import java.io.IOException;
 import java.math.BigDecimal;
@@ -392,6 +394,91 @@ public class SolanaBlockChainImpl implements SolanaBlockChain {
         return Set.copyOf(accountInfos);
     }
 
+    @Override
+    public ΩSolanaTransactionSignatureΩ sendTransaction(
+            SolanaSignedTransaction transaction
+    ) throws IOException, InterruptedException {
+        String jsonBody = createSendTransactionBody(transaction);
+
+        HttpRequest request = HttpRequest.newBuilder()
+                .uri(URI.create(RPC_URL))
+                .header("Content-Type", "application/json")
+                .POST(HttpRequest.BodyPublishers.ofString(jsonBody))
+                .build();
+
+        HttpResponse<String> response = sendThrottled(request);
+
+        if (response.statusCode() != 200) {
+            throw new IOException(
+                    "Solana sendTransaction RPC call failed: HTTP "
+                            + response.statusCode()
+                            + "\n"
+                            + response.body()
+            );
+        }
+
+        JsonNode root = objectMapper.readTree(response.body());
+
+        JsonNode errorNode = root.get("error");
+
+        if (errorNode != null && !errorNode.isNull()) {
+            throw new IOException(
+                    "Solana sendTransaction RPC error: "
+                            + errorNode.toPrettyString()
+            );
+        }
+
+        JsonNode resultNode = root.get("result");
+
+        if (resultNode == null
+                || !resultNode.isTextual()
+                || resultNode.asText().isBlank()) {
+            throw new IOException(
+                    "Solana sendTransaction response did not contain "
+                            + "a transaction signature: "
+                            + response.body()
+            );
+        }
+
+        ΩSolanaTransactionSignatureΩ signature = resultNode.asText();
+        return signature;
+    }
+
+    private String createSendTransactionBody(
+            SolanaSignedTransaction transaction
+    ) throws IOException {
+        if (transaction == null) {
+            throw new IllegalArgumentException(
+                    "Signed transaction must not be null"
+            );
+        }
+
+        ΩBase64StringΩ serializedTransaction =
+                transaction.serializedTransaction();
+
+        if (serializedTransaction == null
+                || serializedTransaction.isBlank()) {
+            throw new IllegalArgumentException(
+                    "Serialized signed transaction must not be blank"
+            );
+        }
+
+        ObjectNode request = objectMapper.createObjectNode();
+        request.put("jsonrpc", "2.0");
+        request.put("id", 1);
+        request.put("method", "sendTransaction");
+
+        ArrayNode params = request.putArray("params");
+        params.add(serializedTransaction);
+
+        ObjectNode configuration = params.addObject();
+        configuration.put("encoding", "base64");
+        configuration.put("skipPreflight", false);
+        configuration.put("preflightCommitment", "confirmed");
+
+        return objectMapper.writeValueAsString(request);
+    }
+
     private String createGetProgramAccountsBody(
             ΩSolanaProgramIdΩ programId,
             Set<SolanaProgramAccountMemcmpFilter> filters