[PATCH 5 of 8] QualityMeasurementFactory: Doc about singleton usage

[Wald Commits]

# HG changeset patch
# User Felix Wolfsteller <felix.wolfsteller at intevation.de>
# Date 1375866055 -7200
# Node ID 6a67a8f01f5b6203d94b1804de28ffe0313f4c7e
# Parent  4902d3ead5411de903b069ecb904fac813e1cc9e
QualityMeasurementFactory: Doc about singleton usage.
Also force it by making constructor private.

diff -r 4902d3ead541 -r 6a67a8f01f5b artifacts/src/main/java/org/dive4elements/river/artifacts/model/minfo/QualityMeasurementFactory.java
--- a/artifacts/src/main/java/org/dive4elements/river/artifacts/model/minfo/QualityMeasurementFactory.java	Wed Aug 07 10:59:53 2013 +0200
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/model/minfo/QualityMeasurementFactory.java	Wed Aug 07 11:00:55 2013 +0200
@@ -86,12 +86,15 @@
         "      m.datum BETWEEN :start AND :end " +
         "ORDER BY m.km";
 
+    /** Transform query result into objects, use INSTANCE singleton. */
     public static final class QualityMeasurementResultTransformer
     extends BasicTransformerAdapter {
 
-        public static QualityMeasurementResultTransformer INSTANCE = new QualityMeasurementResultTransformer();
+        // Make a singleton
+        public static QualityMeasurementResultTransformer INSTANCE =
+            new QualityMeasurementResultTransformer();
 
-        public QualityMeasurementResultTransformer() {
+        private QualityMeasurementResultTransformer() {
         }
 
         @Override