--- a/flys-backend/ChangeLog	Fri Apr 15 16:06:15 2011 +0000
+++ b/flys-backend/ChangeLog	Mon Apr 18 07:29:05 2011 +0000
@@ -1,3 +1,9 @@
+2011-04-18  Ingo Weinzierl <ingo@intevation.de>
+
+	* src/main/java/de/intevation/flys/model/River.java::
+	  Added a new method to determine the gauge based on a given start and end
+	  point of the river.
+
 2011-04-15	Sascha L. Teichmann	<sascha.teichmann@intevation.de>
 
 	* doc/schema/postgresql.sql: Added 'position' column to wst_columns

--- a/flys-backend/src/main/java/de/intevation/flys/model/River.java	Fri Apr 15 16:06:15 2011 +0000
+++ b/flys-backend/src/main/java/de/intevation/flys/model/River.java	Mon Apr 18 07:29:05 2011 +0000
@@ -16,6 +16,12 @@
 
 import java.util.List;
 
+import org.hibernate.Session;
+import org.hibernate.Query;
+
+import de.intevation.flys.backend.SessionHolder;
+
+
 @Entity
 @Table(name = "rivers")
 public class River
@@ -74,6 +80,31 @@
         return name != null ? name : "";
     }
 
+
+    /**
+     * This method returns the first gauge that is intersected by <i>a</i> and
+     * <i>b</i>,
+     *
+     * @param a A start point.
+     * @param b An end point.
+     *
+     * @return the first intersecting gauge.
+     */
+    public Gauge determineGauge(double a, double b) {
+        Session session = SessionHolder.HOLDER.get();
+
+        Query query = session.createQuery(
+            "from Gauge where river=:river " +
+            "and not (range.a > :b or range.b < :a) order by a");
+        query.setParameter("river", this);
+        query.setParameter("a", new BigDecimal(a));
+        query.setParameter("b", new BigDecimal(b));
+
+        List<Gauge> gauges = query.list();
+
+        return gauges != null && gauges.size() > 0 ? gauges.get(0) : null;
+    }
+
     /**
      * Returns the min and max distance of this river. The first position in the
      * resulting array contains the min distance, the second position the max