simplify bytecode transform

Author: zeitlinger

instrumentation/methods/javaagent/src/declarativeConfigTest/java/io/opentelemetry/javaagent/instrumentation/methods/MethodTest.java

@@ -37,6 +37,7 @@ void methodTraced() {
                             equalTo(CODE_NAMESPACE, ConfigTracedCallable.class.getName()),
                             equalTo(CODE_FUNCTION, "call"))));
   }
+
   static class ConfigTracedCallable implements Callable<String> {
 
     @Override

instrumentation/methods/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/methods/MethodInstrumentation.java

@@ -10,9 +10,11 @@
 import static io.opentelemetry.javaagent.extension.matcher.AgentElementMatchers.hasSuperType;
 import static io.opentelemetry.javaagent.instrumentation.methods.MethodSingletons.getBootstrapLoader;
 import static io.opentelemetry.javaagent.instrumentation.methods.MethodSingletons.instrumenter;
+import static net.bytebuddy.matcher.ElementMatchers.any;
 import static net.bytebuddy.matcher.ElementMatchers.isMethod;
 import static net.bytebuddy.matcher.ElementMatchers.named;
 import static net.bytebuddy.matcher.ElementMatchers.namedOneOf;
+import static net.bytebuddy.matcher.ElementMatchers.none;
 
 import io.opentelemetry.api.trace.SpanKind;
 import io.opentelemetry.context.Context;
@@ -40,6 +42,9 @@ public MethodInstrumentation(String className, Map<String, SpanKind> methodNames
 
   @Override
   public ElementMatcher<ClassLoader> classLoaderOptimization() {
+    if (className == null) {
+      return any();
+    }
     ElementMatcher<ClassLoader> delegate = hasClassesNamed(className);
     return target -> {
       // hasClassesNamed does not support null class loader, so we provide a custom loader that
@@ -53,7 +58,7 @@ public ElementMatcher<ClassLoader> classLoaderOptimization() {
 
   @Override
   public ElementMatcher<TypeDescription> typeMatcher() {
-    return hasSuperType(named(className));
+    return className == null ? none() : hasSuperType(named(className));
   }
 
   @Override
@@ -95,9 +100,7 @@ public static void onEnter(
         @Advice.Local("otelScope") Scope scope) {
       Context parentContext = currentContext();
       classAndMethod =
-          MethodAndType.create(
-              ClassAndMethod.create(declaringClass, methodName),
-              spanKind);
+          MethodAndType.create(ClassAndMethod.create(declaringClass, methodName), spanKind);
 
       if (!instrumenter().shouldStart(parentContext, classAndMethod)) {
         return;

instrumentation/methods/javaagent/src/main/java/io/opentelemetry/javaagent/instrumentation/methods/MethodInstrumentationModule.java

@@ -5,16 +5,14 @@
 
 package io.opentelemetry.javaagent.instrumentation.methods;
 
-import static java.util.Collections.emptyList;
-
 import com.google.auto.service.AutoService;
 import io.opentelemetry.api.incubator.config.DeclarativeConfigProperties;
 import io.opentelemetry.api.trace.SpanKind;
 import io.opentelemetry.javaagent.bootstrap.internal.AgentInstrumentationConfig;
 import io.opentelemetry.javaagent.extension.instrumentation.InstrumentationModule;
 import io.opentelemetry.javaagent.extension.instrumentation.TypeInstrumentation;
 import io.opentelemetry.javaagent.tooling.config.MethodsConfigurationParser;
-import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -29,11 +27,18 @@ public class MethodInstrumentationModule extends InstrumentationModule {
 
   public MethodInstrumentationModule() {
     super("methods");
+    typeInstrumentations = createInstrumentations();
+  }
 
+  private static List<TypeInstrumentation> createInstrumentations() {
     DeclarativeConfigProperties methods =
         AgentInstrumentationConfig.get().getDeclarativeConfig("methods");
-    typeInstrumentations =
+    List<TypeInstrumentation> list =
         methods != null ? MethodsConfig.parseDeclarativeConfig(methods) : parseConfigProperties();
+    if (list.isEmpty()) {
+      return Collections.singletonList(new MethodInstrumentation(null, Collections.emptyMap()));
+    }
+    return list;
   }
 
   private static List<TypeInstrumentation> parseConfigProperties() {
@@ -54,19 +59,6 @@ private static List<TypeInstrumentation> parseConfigProperties() {
         .collect(Collectors.toList());
   }
 
-  // the default configuration has empty "otel.instrumentation.methods.include", and so doesn't
-  // generate any TypeInstrumentation for muzzle to analyze
-  @Override
-  public List<String> getAdditionalHelperClassNames() {
-    return typeInstrumentations.isEmpty()
-        ? emptyList()
-        : Arrays.asList(
-            "io.opentelemetry.javaagent.instrumentation.methods.MethodAndType",
-            "io.opentelemetry.javaagent.instrumentation.methods.MethodSingletons",
-            "io.opentelemetry.javaagent.instrumentation.methods.MethodSingletons$1",
-            "io.opentelemetry.javaagent.instrumentation.methods.MethodSingletons$BootstrapLoader");
-  }
-
   @Override
   public List<TypeInstrumentation> typeInstrumentations() {
     return typeInstrumentations;