Simplify decorator API: void return types and factory method naming

dd-java-agent/agent-bootstrap/src/jmh/java/datadog/trace/bootstrap/instrumentation/decorator/HttpServerDecoratorBenchmark.java

@@ -32,6 +32,7 @@
 import org.openjdk.jmh.annotations.Setup;
 import org.openjdk.jmh.annotations.State;
 import org.openjdk.jmh.annotations.Warmup;
+import org.openjdk.jmh.infra.Blackhole;
 
 @State(Scope.Benchmark)
 @Warmup(iterations = 4, time = 30, timeUnit = SECONDS)
@@ -64,8 +65,9 @@ public void setUp() {
   }
 
   @Benchmark
-  public AgentSpan onRequest() {
-    return decorator.onRequest(span, null, request, root());
+  public void onRequest(Blackhole bh) {
+    decorator.onRequest(span, null, request, root());
+    bh.consume(span);
   }
 
   public static class Request {

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

@@ -90,7 +90,7 @@ protected boolean traceAnalyticsDefault() {
     return false;
   }
 
-  public AgentSpan afterStart(final AgentSpan span) {
+  public void afterStart(final AgentSpan span) {
     if (spanType() != null) {
       span.setSpanType(spanType());
     }
@@ -104,64 +104,52 @@ public AgentSpan afterStart(final AgentSpan span) {
 
     // null handled by setMetric
     span.setMetric(traceAnalyticsEntry);
-
-    return span;
   }
 
-  public ContextScope beforeFinish(final ContextScope scope) {
+  public void beforeFinish(final ContextScope scope) {
     beforeFinish(scope.context());
-    return scope;
   }
 
-  public AgentSpan beforeFinish(final AgentSpan span) {
-    return span;
-  }
+  public void beforeFinish(final AgentSpan span) {}
 
-  public Context beforeFinish(final Context context) {
-    return context;
-  }
+  public void beforeFinish(final Context context) {}
 
-  public AgentScope onError(final AgentScope scope, final Throwable throwable) {
+  public void onError(final AgentScope scope, final Throwable throwable) {
     if (scope != null) {
       onError(scope.span(), throwable);
     }
-    return scope;
   }
 
-  public AgentSpan onError(final AgentSpan span, final Throwable throwable) {
-    return onError(span, throwable, ErrorPriorities.DEFAULT);
+  public void onError(final AgentSpan span, final Throwable throwable) {
+    onError(span, throwable, ErrorPriorities.DEFAULT);
   }
 
-  public AgentSpan onError(final AgentSpan span, final Throwable throwable, byte errorPriority) {
+  public void onError(final AgentSpan span, final Throwable throwable, byte errorPriority) {
     if (throwable != null && span != null) {
       span.addThrowable(
           throwable instanceof ExecutionException ? throwable.getCause() : throwable,
           errorPriority);
     }
-    return span;
   }
 
-  public ContextScope onError(final ContextScope scope, final Throwable throwable) {
+  public void onError(final ContextScope scope, final Throwable throwable) {
     if (scope != null) {
       onError(AgentSpan.fromContext(scope.context()), throwable);
     }
-    return scope;
   }
 
-  public AgentSpan onPeerConnection(
-      final AgentSpan span, final InetSocketAddress remoteConnection) {
+  public void onPeerConnection(final AgentSpan span, final InetSocketAddress remoteConnection) {
     if (remoteConnection != null) {
       onPeerConnection(span, remoteConnection.getAddress(), !remoteConnection.isUnresolved());
       setPeerPort(span, remoteConnection.getPort());
     }
-    return span;
   }
 
-  public AgentSpan onPeerConnection(final AgentSpan span, final InetAddress remoteAddress) {
-    return onPeerConnection(span, remoteAddress, true);
+  public void onPeerConnection(final AgentSpan span, final InetAddress remoteAddress) {
+    onPeerConnection(span, remoteAddress, true);
   }
 
-  public AgentSpan onPeerConnection(AgentSpan span, InetAddress remoteAddress, boolean resolved) {
+  public void onPeerConnection(AgentSpan span, InetAddress remoteAddress, boolean resolved) {
     if (remoteAddress != null) {
       String ip = remoteAddress.getHostAddress();
       if (resolved && Config.get().isPeerHostNameEnabled()) {
@@ -173,20 +161,16 @@ public AgentSpan onPeerConnection(AgentSpan span, InetAddress remoteAddress, boo
         span.setTag(Tags.PEER_HOST_IPV6, ip);
       }
     }
-    return span;
   }
 
-  public AgentSpan setPeerPort(AgentSpan span, String port) {
+  public void setPeerPort(AgentSpan span, String port) {
     span.setTag(Tags.PEER_PORT, port);
-
-    return span;
   }
 
-  public AgentSpan setPeerPort(AgentSpan span, int port) {
+  public void setPeerPort(AgentSpan span, int port) {
     if (port > UNSET_PORT) {
       span.setTag(Tags.PEER_PORT, port);
     }
-    return span;
   }
 
   /**

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

@@ -32,7 +32,7 @@ protected String spanKind() {
   }
 
   @Override
-  public AgentSpan afterStart(final AgentSpan span) {
+  public void afterStart(final AgentSpan span) {
     final String service = service();
     if (service != null) {
       span.setServiceName(service, component());
@@ -41,6 +41,6 @@ public AgentSpan afterStart(final AgentSpan span) {
 
     // Generate metrics for all client spans.
     span.setMeasured(true);
-    return super.afterStart(span);
+    super.afterStart(span);
   }
 }

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

@@ -6,8 +6,8 @@ public abstract class DBTypeProcessingDatabaseClientDecorator<CONNECTION>
     extends DatabaseClientDecorator<CONNECTION> {
 
   @Override
-  public AgentSpan afterStart(AgentSpan span) {
+  public void afterStart(AgentSpan span) {
     processDatabaseType(span, dbType());
-    return super.afterStart(span);
+    super.afterStart(span);
   }
 }

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

@@ -66,9 +66,8 @@ public String getDbType() {
    *
    * @param span
    * @param connection
-   * @return
    */
-  public AgentSpan onConnection(final AgentSpan span, final CONNECTION connection) {
+  public void onConnection(final AgentSpan span, final CONNECTION connection) {
     if (connection != null) {
       span.setTag(Tags.DB_USER, dbUser(connection));
       onInstance(span, dbInstance(connection));
@@ -81,18 +80,16 @@ public AgentSpan onConnection(final AgentSpan span, final CONNECTION connection)
         }
       }
     }
-    return span;
   }
 
-  protected AgentSpan onInstance(final AgentSpan span, final String dbInstance) {
+  protected void onInstance(final AgentSpan span, final String dbInstance) {
     if (dbInstance != null) {
       span.setTag(Tags.DB_INSTANCE, dbInstance);
       String serviceName = dbClientService(dbInstance);
       if (null != serviceName) {
         span.setServiceName(serviceName, component());
       }
     }
-    return span;
   }
 
   public String dbService(final String dbType, final String instanceName) {
@@ -114,9 +111,8 @@ public String dbClientService(final String instanceName) {
     return service;
   }
 
-  public AgentSpan onStatement(final AgentSpan span, final CharSequence statement) {
+  public void onStatement(final AgentSpan span, final CharSequence statement) {
     span.setResourceName(statement);
-    return span;
   }
 
   /**

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

@@ -92,7 +92,7 @@ protected boolean shouldSetResourceName() {
             }
           };
 
-  public AgentSpan onRequest(final AgentSpan span, final REQUEST request) {
+  public void onRequest(final AgentSpan span, final REQUEST request) {
     if (request != null) {
       AgentTracer.get()
           .getDataStreamsMonitoring()
@@ -143,10 +143,9 @@ public AgentSpan onRequest(final AgentSpan span, final REQUEST request) {
         ssrfIastCheck(request);
       }
     }
-    return span;
   }
 
-  public AgentSpan onResponse(final AgentSpan span, final RESPONSE response) {
+  public void onResponse(final AgentSpan span, final RESPONSE response) {
     if (response != null) {
       final int status = status(response);
       if (status > UNSET_STATUS) {
@@ -166,7 +165,6 @@ public AgentSpan onResponse(final AgentSpan span, final RESPONSE response) {
         }
       }
     }
-    return span;
   }
 
   public String operationName() {

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

@@ -237,7 +237,7 @@ private void resetServiceNameIfUnderInferredProxy(Context parentContext, AgentSp
             }
           };
 
-  public AgentSpan onRequest(
+  public void onRequest(
       final AgentSpan span,
       final CONNECTION connection,
       final REQUEST request,
@@ -428,7 +428,6 @@ public AgentSpan onRequest(
             DataStreamsTransactionExtractor.Type.HTTP_IN_HEADERS,
             request,
             DSM_TRANSACTION_SOURCE_READER);
-    return span;
   }
 
   protected static AgentSpanContext.Extracted getExtractedSpanContext(Context parentContext) {
@@ -449,7 +448,7 @@ protected BlockResponseFunction createBlockResponseFunction(
     return null;
   }
 
-  public AgentSpan onResponseStatus(final AgentSpan span, final int status) {
+  public void onResponseStatus(final AgentSpan span, final int status) {
     if (status > UNSET_STATUS) {
       span.setHttpStatusCode(status);
       // explicitly set here because some other decorators might already set an error without
@@ -465,7 +464,6 @@ public AgentSpan onResponseStatus(final AgentSpan span, final int status) {
     if (SHOULD_SET_404_RESOURCE_NAME && status == 404) {
       span.setResourceName(NOT_FOUND_RESOURCE_NAME, ResourceNamePriorities.HTTP_404);
     }
-    return span;
   }
 
   /**
@@ -483,7 +481,7 @@ protected boolean isAppSecOnResponseSeparate() {
     return false;
   }
 
-  public AgentSpan onResponse(final AgentSpan span, final RESPONSE response) {
+  public void onResponse(final AgentSpan span, final RESPONSE response) {
     if (response != null) {
       final int status = status(response);
       onResponseStatus(span, status);
@@ -501,7 +499,6 @@ public AgentSpan onResponse(final AgentSpan span, final RESPONSE response) {
         callIGCallbackResponseAndHeaders(span, response, status);
       }
     }
-    return span;
   }
 
   private AgentSpanContext callIGCallbackStart(@Nullable final AgentSpanContext extracted) {
@@ -536,13 +533,12 @@ private AgentSpanContext callIGCallbackStart(@Nullable final AgentSpanContext ex
   }
 
   @Override
-  public AgentSpan onError(final AgentSpan span, final Throwable throwable) {
+  public void onError(final AgentSpan span, final Throwable throwable) {
     if (throwable != null) {
       span.addThrowable(
           throwable instanceof ExecutionException ? throwable.getCause() : throwable,
           ErrorPriorities.HTTP_SERVER_DECORATOR);
     }
-    return span;
   }
 
   private Flow<Void> callIGCallbackRequestHeaders(AgentSpan span, REQUEST_CARRIER carrier) {
@@ -639,7 +635,7 @@ private Flow<Void> callIGCallbackURI(
   }
 
   @Override
-  public Context beforeFinish(Context context) {
+  public void beforeFinish(Context context) {
     AgentSpan span = AgentSpan.fromContext(context);
     if (span != null) {
       onRequestEndForInstrumentationGateway(span);
@@ -648,7 +644,7 @@ public Context beforeFinish(Context context) {
     // Close Serverless Gateway Inferred Span if any
     finishInferredProxySpan(context);
 
-    return super.beforeFinish(context);
+    super.beforeFinish(context);
   }
 
   protected void finishInferredProxySpan(Context context) {

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

@@ -20,10 +20,10 @@ protected boolean endToEndDurationsDefault() {
   }
 
   @Override
-  public AgentSpan afterStart(final AgentSpan span) {
+  public void afterStart(final AgentSpan span) {
     if (endToEndDurationsEnabled) {
       span.beginEndToEnd();
     }
-    return super.afterStart(span);
+    super.afterStart(span);
   }
 }

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

@@ -6,13 +6,12 @@ public abstract class OrmClientDecorator extends DatabaseClientDecorator {
 
   public abstract CharSequence entityName(final Object entity);
 
-  public AgentSpan onOperation(final AgentSpan span, final Object entity) {
+  public void onOperation(final AgentSpan span, final Object entity) {
     if (entity != null) {
       final CharSequence name = entityName(entity);
       if (name != null) {
         span.setResourceName(name);
       } // else we keep any existing resource.
     }
-    return span;
   }
 }

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

@@ -12,10 +12,10 @@ public abstract class ServerDecorator extends BaseDecorator {
       TagMap.Entry.create(DDTags.LANGUAGE_TAG_KEY, DDTags.LANGUAGE_TAG_VALUE);
 
   @Override
-  public AgentSpan afterStart(final AgentSpan span) {
+  public void afterStart(final AgentSpan span) {
     span.setTag(SPAN_KIND_ENTRY);
     span.setTag(LANG_ENTRY);
 
-    return super.afterStart(span);
+    super.afterStart(span);
   }
 }