limit life-time for cached serial ports #6713

java_console/ui/src/main/java/com/rusefi/SerialPortCache.java

@@ -2,6 +2,8 @@ package com.rusefi;
 
 import com.devexperts.logging.Logging;
 
+import java.time.Duration;
+import java.time.Instant;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Map;
@@ -11,15 +13,26 @@ import java.util.Set;
 
 public class SerialPortCache {
     private final static Logging log = Logging.getLogging(SerialPortCache.class);
+    private final static Duration lifeTime = Duration.ofSeconds(2);
 
-    private final Map<String, SerialPortScanner.PortResult> cachedPorts = new HashMap<>();
+    private final Map<String, CachedPort> cachedPorts = new HashMap<>();
 
     Optional<SerialPortScanner.PortResult> get(final String serialPort) {
-        return Optional.ofNullable(cachedPorts.get(serialPort));
+        final CachedPort cachedPort = cachedPorts.get(serialPort);
+        if (cachedPort != null) {
+            if (cachedPort.isExpired()) {
+                cachedPorts.remove(serialPort);
+                log.info("Expired port is removed: " + serialPort);
+
+            } else {
+                return Optional.of(cachedPort.port);
+            }
+        }
+        return Optional.empty();
     }
 
     void put(final SerialPortScanner.PortResult port) {
-        cachedPorts.put(port.port, port);
+        cachedPorts.put(port.port, new CachedPort(port));
     }
 
     void retainAll(final Set<String> serialPortsToRetain) {
@@ -36,7 +49,21 @@ public class SerialPortCache {
         // two steps to avoid ConcurrentModificationException
         toRemove.forEach(p -> {
             cachedPorts.remove(p);
-            log.info("Removing port " + p);
+            log.info("Disappeared port is removed: " + p);
         });
     }
+
+    private static class CachedPort {
+        private final SerialPortScanner.PortResult port;
+        private final Instant expirationTimestamp;
+
+        CachedPort(final SerialPortScanner.PortResult portToCache) {
+            this.port = portToCache;
+            this.expirationTimestamp = Instant.now().plus(lifeTime);
+        }
+
+        boolean isExpired() {
+            return expirationTimestamp.isBefore(Instant.now());
+        }
+    }
 }