From 8097a516da077a655a22100622e2466d584e93be Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Mathieu?= <loikeseke@gmail.com>
Date: Mon, 2 May 2022 17:57:28 +0200
Subject: [PATCH] Improve performance of getOperationName (#230)

---
 .../contrib/interceptor/OpenTracingInterceptor.java      | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/contrib/src/main/java/io/smallrye/opentracing/contrib/interceptor/OpenTracingInterceptor.java b/contrib/src/main/java/io/smallrye/opentracing/contrib/interceptor/OpenTracingInterceptor.java
index 4e65e5a..d2620cf 100644
--- a/contrib/src/main/java/io/smallrye/opentracing/contrib/interceptor/OpenTracingInterceptor.java
+++ b/contrib/src/main/java/io/smallrye/opentracing/contrib/interceptor/OpenTracingInterceptor.java
@@ -159,7 +159,14 @@ private String getOperationName(Method method) {
         } else if (classTraced != null && classTraced.operationName().length() > 0) {
             return classTraced.operationName();
         }
-        return String.format("%s.%s", method.getDeclaringClass().getName(), method.getName());
+
+        // use a StringBuilder with predefined capacity to compute the operation name for performance reason
+        String className = method.getDeclaringClass().getName();
+        String methodName = method.getName();
+        int capacity = className.length() + methodName.length() + 1;
+        StringBuilder builder = new StringBuilder(capacity);
+        builder.append(className).append('.').append(methodName);
+        return builder.toString();
     }
 
     private void logException(Span span, Exception e) {