From 647a2aea646dd45a6563f7db64e29235178d36dc Mon Sep 17 00:00:00 2001
From: Jon Chambers <jon@signal.org>
Date: Fri, 7 Aug 2020 17:32:37 -0400
Subject: [PATCH] Cache a reference to the OS management bean to avoid repeated
 lookups.

---
 .../textsecuregcm/metrics/CpuUsageGauge.java       | 13 +++++++++----
 .../textsecuregcm/metrics/FreeMemoryGauge.java     | 14 +++++++++-----
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/metrics/CpuUsageGauge.java b/service/src/main/java/org/whispersystems/textsecuregcm/metrics/CpuUsageGauge.java
index 77a640163..3deb90b86 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/metrics/CpuUsageGauge.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/metrics/CpuUsageGauge.java
@@ -6,11 +6,16 @@ import com.sun.management.OperatingSystemMXBean;
 import java.lang.management.ManagementFactory;
 
 public class CpuUsageGauge implements Gauge<Integer> {
+
+  private final OperatingSystemMXBean operatingSystemMXBean;
+
+  public CpuUsageGauge() {
+    this.operatingSystemMXBean = (com.sun.management.OperatingSystemMXBean)
+            ManagementFactory.getOperatingSystemMXBean();
+  }
+
   @Override
   public Integer getValue() {
-    OperatingSystemMXBean mbean = (com.sun.management.OperatingSystemMXBean)
-        ManagementFactory.getOperatingSystemMXBean();
-
-    return (int) Math.ceil(mbean.getSystemCpuLoad() * 100);
+    return (int) Math.ceil(operatingSystemMXBean.getSystemCpuLoad() * 100);
   }
 }
diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/metrics/FreeMemoryGauge.java b/service/src/main/java/org/whispersystems/textsecuregcm/metrics/FreeMemoryGauge.java
index ef2232892..ce8bfbf0a 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/metrics/FreeMemoryGauge.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/metrics/FreeMemoryGauge.java
@@ -7,11 +7,15 @@ import java.lang.management.ManagementFactory;
 
 public class FreeMemoryGauge implements Gauge<Long> {
 
+  private final OperatingSystemMXBean operatingSystemMXBean;
+
+  public FreeMemoryGauge() {
+    this.operatingSystemMXBean = (com.sun.management.OperatingSystemMXBean)
+            ManagementFactory.getOperatingSystemMXBean();
+  }
+
   @Override
   public Long getValue() {
-    OperatingSystemMXBean mbean = (com.sun.management.OperatingSystemMXBean)
-        ManagementFactory.getOperatingSystemMXBean();
-
-    return mbean.getFreePhysicalMemorySize();
+    return operatingSystemMXBean.getFreePhysicalMemorySize();
   }
-}
\ No newline at end of file
+}