Working version with semaphore counter and rate limiter

1 files changed, 37 insertions, 0 deletions

diff --git a/src/main/java/com/it_jaros/networkScanner/FdCounter.java b/src/main/java/com/it_jaros/networkScanner/FdCounter.java
new file mode 100644
index 0000000..05eb9a4
--- /dev/null
+++ b/src/main/java/com/it_jaros/networkScanner/FdCounter.java
@@ -0,0 +1,37 @@
+package com.it_jaros.networkScanner;
+
+import java.lang.management.ManagementFactory;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+
+import com.sun.management.UnixOperatingSystemMXBean;
+
+public final class FdCounter implements AutoCloseable {
+    private final UnixOperatingSystemMXBean os =
+            (UnixOperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean();
+    private final ScheduledExecutorService ses =
+            Executors.newSingleThreadScheduledExecutor(Thread.ofPlatform().daemon().factory());
+    private final AtomicLong peak = new AtomicLong(0);
+
+    public void start(long everyMillis) {
+        ses.scheduleAtFixedRate(() -> {
+            long now = os.getOpenFileDescriptorCount();
+            peak.accumulateAndGet(now, Math::max);
+        }, 0, everyMillis, TimeUnit.MILLISECONDS);
+    }
+
+    public long peakOpenFds() {
+        return peak.get();
+    }
+
+    public long maxFds() {
+        return os.getMaxFileDescriptorCount();
+    }
+
+    @Override public void close() {
+        ses.shutdownNow();
+    }
+}
+