Bugfix for npe (#120)

tracer-core/src/main/java/com/alipay/common/tracer/core/reporter/digest/manager/SofaTracerDigestReporterAsyncManager.java

@@ -40,8 +40,10 @@ public static AsyncCommonDigestAppenderManager getSofaTracerDigestReporterAsyncM
         if (asyncCommonDigestAppenderManager == null) {
             synchronized (SofaTracerDigestReporterAsyncManager.class) {
                 if (asyncCommonDigestAppenderManager == null) {
-                    asyncCommonDigestAppenderManager = new AsyncCommonDigestAppenderManager(1024);
-                    asyncCommonDigestAppenderManager.start("NetworkAppender");
+                    AsyncCommonDigestAppenderManager localManager = new AsyncCommonDigestAppenderManager(
+                        1024);
+                    localManager.start("NetworkAppender");
+                    asyncCommonDigestAppenderManager = localManager;
                 }
             }
         }

tracer-core/src/main/java/com/alipay/common/tracer/core/reporter/stat/manager/SofaTracerStatisticReporterCycleTimesManager.java

@@ -64,8 +64,9 @@ public static SofaTracerStatisticReporterManager getSofaTracerStatisticReporterM
         if (existedManager == null) {
             synchronized (cycleTimesManager) {
                 if (cycleTimesManager.get(cycleTime) == null) {
-                    existedManager = new SofaTracerStatisticReporterManager(cycleTime);
-                    cycleTimesManager.put(cycleTime, existedManager);
+                    cycleTimesManager.put(cycleTime, new SofaTracerStatisticReporterManager(
+                        cycleTime));
+                    existedManager = cycleTimesManager.get(cycleTime);
                 }
             }
         }

tracer-core/src/test/java/com/alipay/common/tracer/core/reporter/digest/SofaTracerDigestReporterAsyncManagerTest.java

@@ -0,0 +1,72 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alipay.common.tracer.core.reporter.digest;
+
+import com.alipay.common.tracer.core.appender.manager.AsyncCommonDigestAppenderManager;
+import com.alipay.common.tracer.core.reporter.digest.manager.SofaTracerDigestReporterAsyncManager;
+import com.alipay.common.tracer.core.span.SofaTracerSpan;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.Executors;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.mockito.Mockito.mock;
+
+/**
+ *
+ * @author abby.zh
+ * @version $Id: SofaTracerDigestReporterAsyncManagerTest.java, v 0.1 2018/11/12 4:55 PM abby.zh Exp $
+ * @since 3.0.1
+ */
+public class SofaTracerDigestReporterAsyncManagerTest {
+
+    private SofaTracerSpan sofaTracerSpan;
+
+    @Before
+    public void before() {
+        this.sofaTracerSpan = mock(SofaTracerSpan.class);
+    }
+
+    @Test
+    public void testGetSofaTracerDigestReporterAsyncManager() throws Exception{
+        AtomicInteger npeCount = new AtomicInteger();
+        AtomicInteger successCount = new AtomicInteger();
+        int testTimes = 1000;
+        int threadCount = 100;
+        CountDownLatch latch = new CountDownLatch(testTimes);
+        for (int times = 0 ; times < testTimes; times ++) {
+            Executors.newFixedThreadPool(threadCount).execute(() ->  {
+                    try {
+                        AsyncCommonDigestAppenderManager sofaTracerDigestReporterAsyncManager =
+                                SofaTracerDigestReporterAsyncManager.getSofaTracerDigestReporterAsyncManager();
+                        sofaTracerDigestReporterAsyncManager.append(sofaTracerSpan);
+                        successCount.getAndIncrement();
+                    }catch (NullPointerException e){
+                        npeCount.getAndIncrement();
+                    }finally {
+                        latch.countDown();
+                    }
+            });
+        }
+        latch.await();
+        Assert.assertEquals(0, npeCount.get());
+        Assert.assertEquals(testTimes, successCount.get());
+    }
+}