add helius config parser and factory.

solana/src/main/java/module-info.java

@@ -1,15 +1,18 @@
 module software.sava.solana_services {
-  requires jdk.httpserver;
   requires java.net.http;
+  requires jdk.httpserver;
   requires systems.comodal.json_iterator;
-  requires software.sava.core_services;
-  requires software.sava.anchor_programs;
-  requires software.sava.solana_programs;
-  requires software.sava.rpc;
+
   requires software.sava.core;
+  requires software.sava.rpc;
+  requires software.sava.solana_programs;
+  requires software.sava.solana_web2;
+  requires software.sava.anchor_programs;
+  requires software.sava.core_services;
 
   exports software.sava.services.solana.accounts.lookup;
   exports software.sava.services.solana.accounts.lookup.http;
+  exports software.sava.services.solana.config;
   exports software.sava.services.solana.load_balance;
   exports software.sava.services.solana.remote.call;
 }

solana/src/main/java/software/sava/services/solana/config/HeliusConfig.java

@@ -0,0 +1,81 @@
+package software.sava.services.solana.config;
+
+import software.sava.services.core.remote.call.ErrorHandler;
+import software.sava.services.core.remote.call.ErrorHandlerConfig;
+import software.sava.services.core.remote.load_balance.BalancedItem;
+import software.sava.services.core.remote.load_balance.LoadBalancer;
+import software.sava.services.core.request_capacity.CapacityConfig;
+import software.sava.services.core.request_capacity.ErrorTrackedCapacityMonitor;
+import software.sava.solana.web2.helius.client.http.HeliusClient;
+import systems.comodal.jsoniter.FieldBufferPredicate;
+import systems.comodal.jsoniter.JsonIterator;
+import systems.comodal.jsoniter.ValueType;
+
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpResponse;
+import java.util.Objects;
+
+import static java.util.Objects.requireNonNullElse;
+import static systems.comodal.jsoniter.JsonIterator.fieldEquals;
+
+public record HeliusConfig(URI endpoint,
+                           CapacityConfig capacityConfig,
+                           ErrorHandler errorHandler) {
+
+  public static HeliusConfig parseConfig(final JsonIterator ji) {
+    if (ji.whatIsNext() == ValueType.STRING) {
+      return new HeliusConfig(URI.create(ji.readString()), null, null);
+    } else {
+      final var parser = new Parser();
+      ji.testObject(parser);
+      return parser.create();
+    }
+  }
+
+  public ErrorTrackedCapacityMonitor<HttpResponse<byte[]>> createMonitor(final String serviceName,
+                                                                         final CapacityConfig defaultConfig) {
+    return requireNonNullElse(capacityConfig, defaultConfig).createHttpResponseMonitor(serviceName);
+  }
+
+  public LoadBalancer<HeliusClient> createHeliusClient(final HttpClient httpClient,
+                                                       final CapacityConfig defaultCapacityConfig,
+                                                       final ErrorHandler defaultErrorHandler) {
+    final var capacityMonitor = createMonitor("helius", defaultCapacityConfig);
+    final var client = HeliusClient.createHttpClient(endpoint(), httpClient, capacityMonitor.errorTracker());
+    final var balancedItem = BalancedItem.createItem(
+        client,
+        capacityMonitor,
+        Objects.requireNonNullElse(errorHandler, defaultErrorHandler)
+    );
+    return LoadBalancer.createBalancer(balancedItem);
+  }
+
+  private static final class Parser implements FieldBufferPredicate {
+
+    private URI endpoint;
+    private CapacityConfig capacityConfig;
+    private ErrorHandler errorHandler;
+
+    private Parser() {
+    }
+
+    private HeliusConfig create() {
+      return new HeliusConfig(endpoint, capacityConfig, errorHandler);
+    }
+
+    @Override
+    public boolean test(final char[] buf, final int offset, final int len, final JsonIterator ji) {
+      if (fieldEquals("url", buf, offset, len)) {
+        endpoint = URI.create(ji.readString());
+      } else if (fieldEquals("capacity", buf, offset, len)) {
+        capacityConfig = CapacityConfig.parse(ji);
+      } else if (fieldEquals("backoff", buf, offset, len)) {
+        errorHandler = ErrorHandlerConfig.parseConfig(ji).createHandler();
+      } else {
+        ji.skip();
+      }
+      return true;
+    }
+  }
+}