--- a/flys-backend/src/main/java/de/intevation/flys/model/Gauge.java	Fri Apr 15 10:31:15 2011 +0000
+++ b/flys-backend/src/main/java/de/intevation/flys/model/Gauge.java	Fri Apr 15 13:45:06 2011 +0000
@@ -17,6 +17,12 @@
 import javax.persistence.OneToOne;
 import javax.persistence.OneToMany;
 
+import org.hibernate.Session;
+import org.hibernate.Query;
+
+import de.intevation.flys.backend.SessionHolder;
+
+
 @Entity
 @Table(name = "gauges")
 public class Gauge
@@ -133,5 +139,43 @@
     public void setDischargeTables(List<DischargeTable> dischargeTables) {
         this.dischargeTables = dischargeTables;
     }
+
+
+    /**
+     * Returns min and max W values of this gauge.
+     *
+     *  @return the min and max W value of this gauge [min,max].
+     */
+    public double[] determineMinMaxW() {
+        Session session = SessionHolder.HOLDER.get();
+
+        List<DischargeTable> tables   = getDischargeTables();
+        DischargeTable dischargeTable = null;
+
+        for (DischargeTable tmp: tables) {
+            if (tmp.getKind() == 0) {
+                dischargeTable = tmp;
+                break;
+            }
+        }
+
+        if (dischargeTable == null) {
+            return null;
+        }
+
+        Query query  = session.createQuery(
+            "select min(w) as min, max(w) as max from DischargeTableValue " +
+            "where table_id =:table");
+        query.setParameter("table", dischargeTable.getId());
+
+        List     results = query.list();
+        Object[] result  = (Object[]) results.get(0);
+
+        return result != null
+            ? new double[] {
+                ((BigDecimal) result[0]).doubleValue(),
+                ((BigDecimal) result[1]).doubleValue() }
+            : null;
+    }
 }
 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :