Changeset 11553 in josm for trunk/src/org/openstreetmap/josm/data/Preferences.java

Timestamp:

2017-02-12T16:32:18+01:00 (7 years ago)

Author:

Don-vip

Message:

refactor handling of null values - use Java 8 Optional where possible

File:

• trunk/src/org/openstreetmap/josm/data/Preferences.java (modified) (4 diffs)

trunk/src/org/openstreetmap/josm/data/Preferences.java

@@ -283 +283 @@
      */
     public void removeKeyPreferenceChangeListener(String key, PreferenceChangedListener listener) {
-        ListenerList<PreferenceChangedListener> keyListener = keyListeners.get(key);
-        if (keyListener == null) {
-            throw new IllegalArgumentException("There are no listeners registered for " + key);
-        }
-        keyListener.removeListener(listener);
+        Optional.ofNullable(keyListeners.get(key)).orElseThrow(
+                () -> new IllegalArgumentException("There are no listeners registered for " + key))
+        .removeListener(listener);
     }
 
@@ -1151 +1149 @@
      */
     public <T> List<T> getListOfStructs(String key, Class<T> klass) {
-        List<T> r = getListOfStructs(key, null, klass);
-        if (r == null)
-            return Collections.emptyList();
-        else
-            return r;
+        return Optional.ofNullable(getListOfStructs(key, null, klass)).orElseGet(Collections::emptyList);
     }
 
@@ -1171 +1165 @@
         if (prop == null)
             return def == null ? null : new ArrayList<>(def);
-        List<T> lst = new ArrayList<>();
-        for (Map<String, String> entries : prop) {
-            T struct = deserializeStruct(entries, klass);
-            lst.add(struct);
-        }
-        return lst;
+        return prop.stream().map(p -> deserializeStruct(p, klass)).collect(Collectors.toList());
     }
 
@@ -1204 +1193 @@
         Collection<Map<String, String>> vals = new ArrayList<>();
         for (T struct : l) {
-            if (struct == null) {
-                continue;
-            }
-            vals.add(serializeStruct(struct, klass));
+            if (struct != null) {
+                vals.add(serializeStruct(struct, klass));
+            }
         }
         return vals;