Fix SAT errors (openhab#18047)

Signed-off-by: Leo Siepel <[email protected]>

Author: lsiepel

bundles/org.openhab.binding.digiplex/src/main/java/org/openhab/binding/digiplex/internal/DigiplexAreaConfiguration.java

@@ -12,12 +12,15 @@
  */
 package org.openhab.binding.digiplex.internal;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
+
 /**
  * The {@link DigiplexAreaConfiguration} class contains fields mapping area configuration parameters.
  *
  * @author Robert Michalak - Initial contribution
  */
+@NonNullByDefault
 public class DigiplexAreaConfiguration {
 
-    public int refreshPeriod;
+    public int refreshPeriod = 60;
 }

bundles/org.openhab.binding.digiplex/src/main/java/org/openhab/binding/digiplex/internal/DigiplexBridgeConfiguration.java

@@ -12,13 +12,16 @@
  */
 package org.openhab.binding.digiplex.internal;
 
+import org.eclipse.jdt.annotation.NonNullByDefault;
+
 /**
  * The {@link DigiplexBridgeConfiguration} class contains fields mapping bridge configuration parameters.
  *
  * @author Robert Michalak - Initial contribution
  */
+@NonNullByDefault
 public class DigiplexBridgeConfiguration {
 
-    public String port;
-    public int baudrate;
+    public String port = "";
+    public int baudrate = 2400;
 }

bundles/org.openhab.binding.digiplex/src/main/java/org/openhab/binding/digiplex/internal/handler/DigiplexBridgeHandler.java

@@ -102,7 +102,7 @@ public DigiplexBridgeHandler(Bridge bridge, SerialPortManager serialPortManager)
     @Override
     public void initialize() {
         config = getConfigAs(DigiplexBridgeConfiguration.class);
-        if (config.port == null) {
+        if (config.port.isBlank()) {
             updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.CONFIGURATION_ERROR, "Port must be set!");
             return;
         }