Merge pull request #754 from peng-yongsheng/fixed/id_increment_bug

Fixed the id auto increment bug

apm-collector/apm-collector-analysis/analysis-register/register-provider/src/main/java/org/apache/skywalking/apm/collector/analysis/register/provider/register/IdAutoIncrement.java

@@ -25,18 +25,20 @@ public enum IdAutoIncrement {
     INSTANCE;
 
     public int increment(int min, int max) {
-        int instanceId;
+        int id;
         if (min == max) {
-            instanceId = -1;
+            if (min == 0) {
+                id = -1;
+            } else {
+                id = 1;
+            }
         } else if (min + max == 0) {
-            instanceId = max + 1;
+            id = max + 1;
         } else if (min + max > 0) {
-            instanceId = min - 1;
-        } else if (max < 0) {
-            instanceId = 1;
+            id = min - 1;
         } else {
-            instanceId = max + 1;
+            id = max + 1;
         }
-        return instanceId;
+        return id;
     }
 }

apm-collector/apm-collector-analysis/analysis-register/register-provider/src/test/java/org/apache/skywalking/apm/collector/analysis/register/provider/register/IdAutoIncrementTestCase.java

+/*
+ * 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 org.apache.skywalking.apm.collector.analysis.register.provider.register;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+/**
+ * @author peng-yongsheng
+ */
+public class IdAutoIncrementTestCase {
+
+    @Test
+    public void testIncrement() {
+        int id = IdAutoIncrement.INSTANCE.increment(0, 0);
+        Assert.assertEquals(-1, id);
+
+        id = IdAutoIncrement.INSTANCE.increment(-1, -1);
+        Assert.assertEquals(1, id);
+
+        id = IdAutoIncrement.INSTANCE.increment(-1, 1);
+        Assert.assertEquals(2, id);
+
+        id = IdAutoIncrement.INSTANCE.increment(-1, 2);
+        Assert.assertEquals(-2, id);
+
+        id = IdAutoIncrement.INSTANCE.increment(-2, 2);
+        Assert.assertEquals(3, id);
+    }
+}