From 5a53b1d2aa71b7454e2ad2b43d9cb2c531b29eef Mon Sep 17 00:00:00 2001
From: Jerry Lee <oldratlee@gmail.com>
Date: Sat, 12 Dec 2015 00:03:18 +0800
Subject: [PATCH] add gc operation output for DtTransferInfo in MTC #53

---
 ...acerUseDemo_WeakReferenceInsteadOfRefCounter.java | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/test/java/com/alibaba/mtc/demo/distributed_tracer/DistributedTracerUseDemo_WeakReferenceInsteadOfRefCounter.java b/src/test/java/com/alibaba/mtc/demo/distributed_tracer/DistributedTracerUseDemo_WeakReferenceInsteadOfRefCounter.java
index 34eda8816..a48356448 100644
--- a/src/test/java/com/alibaba/mtc/demo/distributed_tracer/DistributedTracerUseDemo_WeakReferenceInsteadOfRefCounter.java
+++ b/src/test/java/com/alibaba/mtc/demo/distributed_tracer/DistributedTracerUseDemo_WeakReferenceInsteadOfRefCounter.java
@@ -54,6 +54,14 @@ public String toString() {
                     ", leafSpanIdInfo=" + leafSpanIdInfo +
                     '}';
         }
+
+        // Output GC operation
+        @Override
+        protected void finalize() throws Throwable {
+            System.out.printf("DEBUG: gc DtTransferInfo traceId %s in thread %s: %s\n",
+                    traceId, Thread.currentThread().getName(), this);
+            super.finalize();
+        }
     }
 
     private static MtContextThreadLocal<DtTransferInfo> transferInfo = new MtContextThreadLocal<DtTransferInfo>();
@@ -78,6 +86,7 @@ public static void main(String[] args) throws Exception {
         }
 
         Thread.sleep(1000);
+        // help to check GC status
         System.gc();
         Thread.sleep(1000);
     }
@@ -108,6 +117,9 @@ static void rpcInvokeIn() {
         // DistributedTracer Framework Code
         ////////////////////////////////////////////////
         System.out.printf("Finished Rpc call %s with span %s.\n", traceId, leafSpanIdInfo);
+
+        // release context in ThreadLocal, avoid to be hold by thread, GC friendly.
+        transferInfo.remove();
     }
 
     static void syncMethod() {