Extracting span kind & language into static TagMap.Entry objects (#10495)

Extracting into span kind & language into static TagMap.Entry objects that can be reused

Merge branch 'master' into dougqh/server-decorator-entry-reuse

Merge branch 'master' into dougqh/server-decorator-entry-reuse

Merge branch 'master' into dougqh/server-decorator-entry-reuse

Updating tests

Merge branch 'dougqh/server-decorator-entry-reuse' of github.com:DataDog/dd-trace-java into dougqh/server-decorator-entry-reuse

Merge branch 'master' into dougqh/server-decorator-entry-reuse

Co-authored-by: devflow.devflow-routing-intake <devflow.devflow-routing-intake@kubernetes.us1.ddbuild.io>

Author: dougqh

dd-java-agent/agent-bootstrap/src/main/java/datadog/trace/bootstrap/instrumentation/decorator/ServerDecorator.java

@@ -1,15 +1,21 @@
 package datadog.trace.bootstrap.instrumentation.decorator;
 
 import datadog.trace.api.DDTags;
+import datadog.trace.api.TagMap;
 import datadog.trace.bootstrap.instrumentation.api.AgentSpan;
 import datadog.trace.bootstrap.instrumentation.api.Tags;
 
 public abstract class ServerDecorator extends BaseDecorator {
+  private static final TagMap.Entry SPAN_KIND_ENTRY =
+      TagMap.Entry.create(Tags.SPAN_KIND, Tags.SPAN_KIND_SERVER);
+  private static final TagMap.Entry LANG_ENTRY =
+      TagMap.Entry.create(DDTags.LANGUAGE_TAG_KEY, DDTags.LANGUAGE_TAG_VALUE);
 
   @Override
   public AgentSpan afterStart(final AgentSpan span) {
-    span.setTag(Tags.SPAN_KIND, Tags.SPAN_KIND_SERVER);
-    span.setTag(DDTags.LANGUAGE_TAG_KEY, DDTags.LANGUAGE_TAG_VALUE);
+    span.setTag(SPAN_KIND_ENTRY);
+    span.setTag(LANG_ENTRY);
+
     return super.afterStart(span);
   }
 }

dd-java-agent/agent-bootstrap/src/test/groovy/datadog/trace/bootstrap/instrumentation/decorator/BaseDecoratorTest.groovy

@@ -30,9 +30,11 @@ class BaseDecoratorTest extends DDSpecification {
     1 * spanContext.setIntegrationName("test-component")
     _ * span.setTag(_)
     _ * span.setTag(_, _) // Want to allow other calls from child implementations.
+    _ * span.setTag(_)
     _ * span.setMeasured(true)
     _ * span.setMetric(_)
     _ * span.setMetric(_, _)
+    _ * span.setMetric(_)
     _ * span.setServiceName(_, _)
     _ * span.setOperationName(_)
     _ * span.setSamplingPriority(_)

dd-java-agent/agent-bootstrap/src/test/groovy/datadog/trace/bootstrap/instrumentation/decorator/ServerDecoratorTest.groovy

@@ -22,11 +22,11 @@ class ServerDecoratorTest extends BaseDecoratorTest {
     decorator.afterStart(span)
 
     then:
-    1 * span.setTag(LANGUAGE_TAG_KEY, LANGUAGE_TAG_VALUE)
+    1 * span.setTag(TagMap.Entry.create(LANGUAGE_TAG_KEY, LANGUAGE_TAG_VALUE))
     1 * span.setTag(TagMap.Entry.create(COMPONENT, "test-component"))
     1 * span.context() >> spanContext
     1 * spanContext.setIntegrationName("test-component")
-    1 * span.setTag(SPAN_KIND, "server")
+    1 * span.setTag(TagMap.Entry.create(SPAN_KIND, "server"))
     1 * span.setSpanType(decorator.spanType())
     if (decorator.traceAnalyticsEnabled) {
       1 * span.setMetric(TagMap.Entry.create(ANALYTICS_SAMPLE_RATE, 1.0))