Move SpanTypeDecorator to SpanTypeRule

dd-trace-ot/src/main/java/datadog/opentracing/decorators/DDDecoratorsFactory.java

@@ -25,8 +25,7 @@ public class DDDecoratorsFactory {
             new ResourceNameDecorator(),
             new ServiceNameDecorator(),
             new ServiceNameDecorator("service", false),
-            new ServletContextDecorator(),
-            new SpanTypeDecorator())) {
+            new ServletContextDecorator())) {
 
       if (Config.get().isDecoratorEnabled(decorator.getClass().getSimpleName())) {
         decorators.add(decorator);

dd-trace-ot/src/main/java/datadog/opentracing/decorators/SpanTypeDecorator.java

@@ -1,18 +0,0 @@
-package datadog.opentracing.decorators;
-
-import datadog.opentracing.DDSpanContext;
-import datadog.trace.api.DDTags;
-
-public class SpanTypeDecorator extends AbstractDecorator {
-
-  public SpanTypeDecorator() {
-    super();
-    setMatchingTag(DDTags.SPAN_TYPE);
-  }
-
-  @Override
-  public boolean shouldSetTag(final DDSpanContext context, final String tag, final Object value) {
-    context.setSpanType(String.valueOf(value));
-    return false;
-  }
-}

dd-trace-ot/src/main/java/datadog/trace/common/processor/TraceProcessor.java

@@ -3,6 +3,7 @@ package datadog.trace.common.processor;
 import datadog.opentracing.DDSpan;
 import datadog.trace.api.Config;
 import datadog.trace.common.processor.rule.ErrorRule;
+import datadog.trace.common.processor.rule.SpanTypeRule;
 import datadog.trace.common.processor.rule.Status404Rule;
 import datadog.trace.common.processor.rule.Status5XXRule;
 import datadog.trace.common.processor.rule.URLAsResourceNameRule;
@@ -17,7 +18,11 @@ public class TraceProcessor {
   final Rule[] DEFAULT_RULES =
       new Rule[] {
         // Rules are applied in order.
-        new Status5XXRule(), new ErrorRule(), new URLAsResourceNameRule(), new Status404Rule(),
+        new SpanTypeRule(),
+        new Status5XXRule(),
+        new ErrorRule(),
+        new URLAsResourceNameRule(),
+        new Status404Rule(),
       };
 
   private final List<Rule> rules;

dd-trace-ot/src/main/java/datadog/trace/common/processor/rule/ErrorRule.java

@@ -6,7 +6,7 @@ import io.opentracing.tag.Tags;
 import java.util.Collection;
 import java.util.Map;
 
-/** Converts error tag to error field */
+/** Converts error tag to field */
 public class ErrorRule implements TraceProcessor.Rule {
   @Override
   public String[] aliases() {

dd-trace-ot/src/main/java/datadog/trace/common/processor/rule/SpanTypeRule.java

@@ -0,0 +1,24 @@
+package datadog.trace.common.processor.rule;
+
+import datadog.opentracing.DDSpan;
+import datadog.trace.api.DDTags;
+import datadog.trace.common.processor.TraceProcessor;
+import java.util.Collection;
+import java.util.Map;
+
+/** Converts span type tag to field */
+public class SpanTypeRule implements TraceProcessor.Rule {
+  @Override
+  public String[] aliases() {
+    return new String[] {"SpanTypeDecorator"};
+  }
+
+  @Override
+  public void processSpan(
+      final DDSpan span, final Map<String, String> meta, final Collection<DDSpan> trace) {
+    if (meta.containsKey(DDTags.SPAN_TYPE)) {
+      span.setSpanType(meta.get(DDTags.SPAN_TYPE));
+      span.setTag(DDTags.SPAN_TYPE, (String) null); // Remove the tag
+    }
+  }
+}