Streamline HPSF CustomProperties collection retrieval

Reduce the number of map lookups necessary to compute the return values for methods that return collections of property details. Since we maintain parity between the `props` and `dictionary` contents, when retrieving property details, we can reference the `props` directly and avoid the `dictionary` indirection.

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1887453 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/poi/hpsf/CustomProperties.java

@@ -219,9 +219,7 @@ public class CustomProperties implements Map<String,Object> {
      */
     public List<CustomProperty> properties() {
         List<CustomProperty> list = new ArrayList<>(props.size());
-        for (Long l : dictionary.keySet()) {
-            list.add(props.get(l));
-        }
+        list.addAll(props.values());
         return Collections.unmodifiableList(list);
     }
     
@@ -231,8 +229,8 @@ public class CustomProperties implements Map<String,Object> {
     @Override
     public Collection<Object> values() {
         List<Object> list = new ArrayList<>(props.size());
-        for (Long l : dictionary.keySet()) {
-            list.add(props.get(l).getValue());
+        for (CustomProperty property : props.values()) {
+            list.add(property.getValue());
         }
         return Collections.unmodifiableCollection(list);
     }
@@ -240,8 +238,8 @@ public class CustomProperties implements Map<String,Object> {
     @Override
     public Set<Entry<String, Object>> entrySet() {
         Map<String,Object> set = new LinkedHashMap<>(props.size());
-        for (Entry<Long,String> se : dictionary.entrySet()) {
-            set.put(se.getValue(), props.get(se.getKey()).getValue());
+        for (CustomProperty property : props.values()) {
+            set.put(property.getName(), property.getValue());
         }
         return Collections.unmodifiableSet(set.entrySet());
     }