More flexible APIs. support null and empty strings

Author: cyrille-leclerc

src/main/java/com/cloudbees/syslog/Facility.java

@@ -168,13 +168,13 @@ public static Facility fromNumericalCode(int numericalCode) throws IllegalArgume
     }
 
     /**
-     * @param label Syslog facility textual code
+     * @param label Syslog facility textual code. {@code null} or empty returns {@code null}
      * @return Syslog facility, {@code null} if given value is {@code null}
      * @throws IllegalArgumentException the given value is not a valid Syslog facility textual code
      */
     @Nullable
     public static Facility fromLabel(String label) throws IllegalArgumentException {
-        if (label == null)
+        if (label == null || label.isEmpty())
             return null;
 
         Facility facility = facilityFromLabel.get(label);

src/main/java/com/cloudbees/syslog/Severity.java

@@ -94,13 +94,13 @@ public static Severity fromNumericalCode(int numericalCode) throws IllegalArgume
     }
 
     /**
-     * @param label Syslog severity textual code
+     * @param label Syslog severity textual code. {@code null} or empty returns {@code null}
      * @return Syslog severity, {@code null} if given value is {@code null}
      * @throws IllegalArgumentException the given value is not a valid Syslog severity textual code
      */
     @Nullable
     public static Severity fromLabel(@Nullable String label) throws IllegalArgumentException {
-        if (label == null)
+        if (label == null || label.isEmpty())
             return null;
 
         Severity severity = severityFromLabel.get(label);

src/main/java/com/cloudbees/syslog/integration/jul/util/LevelHelper.java

@@ -68,11 +68,13 @@ public class LevelHelper {
     /**
      * Simplification: use delegate to {@link Level#parse(String)} even if the behavior is slightly different for localized log levels.
      *
-     * @param name
+     * @param name {@code null} or empty returns {@code null}
      * @return
      */
     @Nullable
-    public static Level findLevel(@Nonnull String name) {
+    public static Level findLevel(@Nullable String name) {
+        if(name == null || name.isEmpty())
+            return null;
         return Level.parse(name);
 
     }