From d28c9d4def2602d8e7afc10572de536c2c360a33 Mon Sep 17 00:00:00 2001
From: "bohr.qiu" <bohr.qiu@gmail.com>
Date: Fri, 21 Sep 2018 12:06:52 +0800
Subject: [PATCH] add jvm command display file descriptor count

---
 .../core/command/monitor200/JvmCommand.java    | 18 +++++++++++++++++-
 site/src/site/sphinx/en/jvm.md                 | 11 +++++++++++
 site/src/site/sphinx/jvm.md                    | 14 ++++++++++++--
 3 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/core/src/main/java/com/taobao/arthas/core/command/monitor200/JvmCommand.java b/core/src/main/java/com/taobao/arthas/core/command/monitor200/JvmCommand.java
index 540112b21..7f3f295c2 100644
--- a/core/src/main/java/com/taobao/arthas/core/command/monitor200/JvmCommand.java
+++ b/core/src/main/java/com/taobao/arthas/core/command/monitor200/JvmCommand.java
@@ -14,6 +14,7 @@ import com.taobao.text.ui.TableElement;
 import com.taobao.text.util.RenderUtil;
 
 import java.lang.management.*;
+import java.lang.reflect.Method;
 import java.text.SimpleDateFormat;
 import java.util.Collection;
 import java.util.Date;
@@ -74,12 +75,27 @@ public class JvmCommand extends AnnotatedCommand {
         table.row("", "");
         table.row(true, label("THREAD").style(Decoration.bold.bold()));
         drawThreadTable(table);
-
+        table.row("", "");
+        table.row(true, label("FILE-DESCRIPTOR").style(Decoration.bold.bold()));
+        drawFileDescriptorTable(table);
         process.write(RenderUtil.render(table, process.width()));
         process.write(affect.toString()).write("\n");
         process.end();
     }
 
+    private void drawFileDescriptorTable(TableElement table) {
+        table.row("MAX-FILE-DESCRIPTOR-COUNT", "" + invokeFileDescriptor(operatingSystemMXBean, "getMaxFileDescriptorCount"))
+                .row("OPEN-FILE-DESCRIPTOR-COUNT", "" + invokeFileDescriptor(operatingSystemMXBean, "getOpenFileDescriptorCount"));
+    }
+    private long invokeFileDescriptor(OperatingSystemMXBean os, String name) {
+        try {
+            final Method method = os.getClass().getDeclaredMethod(name);
+            method.setAccessible(true);
+            return (Long) method.invoke(os);
+        } catch (Exception e) {
+            return -1;
+        }
+    }
     private String toCol(Collection<String> strings) {
         final StringBuilder colSB = new StringBuilder();
         if (strings.isEmpty()) {
diff --git a/site/src/site/sphinx/en/jvm.md b/site/src/site/sphinx/en/jvm.md
index 74701b3b4..b787281b7 100644
--- a/site/src/site/sphinx/en/jvm.md
+++ b/site/src/site/sphinx/en/jvm.md
@@ -87,6 +87,11 @@ $ jvm
                       PEAK-COUNT     18
                       STARTED-COUNT  19
                       DEADLOCK-COUNT  0
+                      
+ FILE-DESCRIPTOR
+ 
+                      MAX-FILE-DESCRIPTOR-COUNT  10240
+                      OPEN-FILE-DESCRIPTOR-COUNT 648
 Affect cost in 2 ms.
 ```
 
@@ -97,3 +102,9 @@ Affect cost in 2 ms.
 * PEAK-COUNT: the maximum count of the live threads since JVM starts
 * STARTED-COUNT: the total count of the created threads since JVM starts
 * DEADLOCK-COUNT: the count of deadlock threads 
+
+
+### fileDescriptor-related
+
+* MAX-FILE-DESCRIPTOR-COUNT：the count of max file descriptor JVM process can open
+* OPEN-FILE-DESCRIPTOR-COUNT：the current count of file descriptor JVM process open
\ No newline at end of file
diff --git a/site/src/site/sphinx/jvm.md b/site/src/site/sphinx/jvm.md
index 2278ddedb..4e668aca7 100644
--- a/site/src/site/sphinx/jvm.md
+++ b/site/src/site/sphinx/jvm.md
@@ -87,6 +87,11 @@ $ jvm
                       PEAK-COUNT     18
                       STARTED-COUNT  19
                       DEADLOCK-COUNT  0
+
+ FILE-DESCRIPTOR
+ 
+                      MAX-FILE-DESCRIPTOR-COUNT  10240
+                      OPEN-FILE-DESCRIPTOR-COUNT 648
                       
 Affect cost in 2 ms.
 ```
@@ -96,5 +101,10 @@ Affect cost in 2 ms.
 * COUNT: JVM当前活跃的线程数
 * DAEMON-COUNT: JVM当前活跃的守护线程数
 * PEAK-COUNT: 从JVM启动开始曾经活着的最大线程数
-* STARTED-COUNT: 从jvm启动开始总共启动过的线程次数
-* DEADLOCK-COUNT: JVM当前死锁的线程数
\ No newline at end of file
+* STARTED-COUNT: 从JVM启动开始总共启动过的线程次数
+* DEADLOCK-COUNT: JVM当前死锁的线程数
+
+### 文件描述符相关
+
+* MAX-FILE-DESCRIPTOR-COUNT：JVM进程最大可以打开的文件描述符数
+* OPEN-FILE-DESCRIPTOR-COUNT：JVM当前打开的文件描述符数