Register types for reflection and use holder idiom

DataDog · Apr 7, 2024 · e2a383c · e2a383c
1 parent 734e3c5
commit e2a383c
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Showing 2 changed files with 25 additions and 5 deletions.
diff --git a/.../src/main/resources/META-INF/native-image/com.datadoghq/dd-java-agent/reflect-config.json b/.../src/main/resources/META-INF/native-image/com.datadoghq/dd-java-agent/reflect-config.json
@@ -47,6 +47,19 @@
       {"name": "fromJson"}
     ]
   },
+  {
+    "name" : "datadog.trace.agent.core.DDSpanLink$SpanLinkAdapter",
+    "methods": [
+      {"name": "toSpanLinkJson"}
+    ]
+  },
+  {
+    "name" : "datadog.trace.agent.core.DDSpanLink$SpanLinkJson",
+    "allDeclaredConstructors" : true,
+    "allPublicConstructors" : true,
+    "allDeclaredFields" : true,
+    "allPublicFields" : true
+  },
   {
     "name" : "datadog.trace.instrumentation.springweb.HandlerMappingResourceNameFilter",
     "methods": [

diff --git a/dd-trace-core/src/main/java/datadog/trace/core/DDSpanLink.java b/dd-trace-core/src/main/java/datadog/trace/core/DDSpanLink.java
@@ -23,8 +23,6 @@ public class DDSpanLink extends SpanLink {
   private static final Logger LOGGER = LoggerFactory.getLogger(DDSpanLink.class);
   /** The maximum of characters a span tag value can hold. */
   private static final int TAG_MAX_LENGTH = 25_000;
-  /** JSON encoder (lazily initialized) */
-  private static JsonAdapter<AgentSpanLink> encoder;
 
   protected DDSpanLink(
       DDTraceId traceId, long spanId, byte traceFlags, String traceState, Attributes attributes) {
@@ -95,11 +93,20 @@ public static String toTag(List<AgentSpanLink> links) {
   }
 
   private static JsonAdapter<AgentSpanLink> getEncoder() {
-    if (encoder == null) {
+    return EncoderHolder.ENCODER;
+  }
+
+  /**
+   * JSON encoder (lazily initialized). This is not folded at native image build time, so it works
+   * as expected.
+   */
+  private static class EncoderHolder {
+    static final JsonAdapter<AgentSpanLink> ENCODER = createEncoder();
+
+    private static JsonAdapter<AgentSpanLink> createEncoder() {
       Moshi moshi = new Moshi.Builder().add(new SpanLinkAdapter()).build();
-      encoder = moshi.adapter(AgentSpanLink.class);
+      return moshi.adapter(AgentSpanLink.class);
     }
-    return encoder;
   }
 
   private static class SpanLinkAdapter {