add PushService for DruidMonitor

src/main/java/com/alibaba/druid/util/DaemonThreadFactory.java

@@ -0,0 +1,28 @@
+package com.alibaba.druid.util;
+
+import java.util.concurrent.ThreadFactory;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * @author sandzhang<sandzhangtoo@gmail.com>
+ */
+public class DaemonThreadFactory implements ThreadFactory {
+
+    private AtomicInteger threadNo = new AtomicInteger(1);
+    private final String  nameStart;
+    private final String  nameEnd  = "]";
+
+    public DaemonThreadFactory(String poolName){
+        nameStart = "[" + poolName + "-";
+    }
+
+    public Thread newThread(Runnable r) {
+        Thread newThread = new Thread(r, nameStart + threadNo.getAndIncrement() + nameEnd);
+        newThread.setDaemon(true);
+        if (newThread.getPriority() != Thread.NORM_PRIORITY) {
+            newThread.setPriority(Thread.NORM_PRIORITY);
+        }
+        return newThread;
+    }
+
+}