[PATCH 1 of 2] Do not require identical values when searching for a main value

[Wald Commits]

# HG changeset patch
# User Tom Gottfried <tom at intevation.de>
# Date 1668091147 -3600
#      Thu Nov 10 15:39:07 2022 +0100
# Branch 3.2.x
# Node ID a83029cc7e6afd3e7198006259600cea890248ac
# Parent  0a2e1e604f43cc2a470a0140b83dc0120f5dd73d
Do not require identical values when searching for a main value

E.g. a value obtained using WQ.getRawValue() is not necessarily
numerically identical, but nevertheless to be considered equal,
to a matching Q main value.
Fixes wrong descriptions in the result of a water level calculation,
where not finding a matching main value led to the value being used
as description instead of the name of the matching main value.

diff -r 0a2e1e604f43 -r a83029cc7e6a artifacts/src/main/java/org/dive4elements/river/utils/RiverUtils.java
--- a/artifacts/src/main/java/org/dive4elements/river/utils/RiverUtils.java	Wed Oct 12 16:54:12 2022 +0200
+++ b/artifacts/src/main/java/org/dive4elements/river/utils/RiverUtils.java	Thu Nov 10 15:39:07 2022 +0100
@@ -27,6 +27,7 @@
 import org.dive4elements.river.model.Gauge;
 import org.dive4elements.river.model.MainValue;
 import org.dive4elements.river.model.River;
+import org.dive4elements.river.backend.utils.EpsilonComparator;
 import org.dive4elements.river.backend.utils.StringUtil;
 
 import gnu.trove.TDoubleArrayList;
@@ -63,6 +64,12 @@
     private static Logger log = LogManager.getLogger(RiverUtils.class);
 
     /**
+     * Comparator to compare Q values with Q main values.
+     */
+    private static final EpsilonComparator MAIN_VALUE_Q_COMP =
+        new EpsilonComparator(1e-3);
+
+    /**
      * Enum that represents the 5 possible WQ modes in FLYS. The 5 values are
      * <i>QFREE</i> <i>QGAUGE</i> <i>WGAUGE</i> <i>WFREE</i> and <i>NONE</i>.
      */
@@ -574,17 +581,15 @@
 
     public static String getNamedMainValue(Gauge gauge, double value) {
         List<MainValue> mainValues = gauge.getMainValues();
-        log.debug("Search named main value for: " + value);
 
         for (MainValue mv: mainValues) {
-            if (mv.getValue().doubleValue() == value) {
-                log.debug("Found named main value: "
-                    + mv.getMainValue().getName());
+            if (MAIN_VALUE_Q_COMP.compare(
+                    mv.getValue().doubleValue(), value) == 0
+            ) {
                 return mv.getMainValue().getName();
             }
         }
 
-        log.debug("Did not find a named main value for: " + value);
         return null;
     }