--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/artifacts/src/main/java/org/dive4elements/river/artifacts/model/CrossSectionFactory.java	Thu Apr 25 15:23:37 2013 +0200
@@ -0,0 +1,112 @@
+package org.dive4elements.river.artifacts.model;
+
+import java.util.List;
+
+import net.sf.ehcache.Cache;
+import net.sf.ehcache.Element;
+
+import org.dive4elements.river.backend.SessionHolder;
+import org.dive4elements.river.model.CrossSection;
+import org.dive4elements.river.model.River;
+
+import org.dive4elements.river.artifacts.cache.CacheFactory;
+
+import org.hibernate.Session;
+import org.hibernate.Query;
+
+
+/**
+ * Get Cross Sections.
+ */
+public class CrossSectionFactory {
+
+    protected final static String CACHE_NAME = "cross_sections";
+
+    // TODO use caching consistently, streamline acces.
+    /**
+     * Get CrossSections for an instantiated River.
+     *
+     * @param river river object.
+     *
+     * @return List of Cross Sections of river.
+     */
+    public static List<CrossSection> getCrossSections(River river) {
+        return getCrossSections(river.getName());
+    }
+
+
+    /**
+     * Get Cross Sections for a river by name.
+     *
+     * @param riverName name of the river of interest.
+     *
+     * @return List of Cross Sections of river.
+     */
+    public static List<CrossSection> getCrossSections(String riverName) {
+        Session session = SessionHolder.HOLDER.get();
+        Query query = session.createQuery(
+            "from CrossSection where river.name = :rivername");
+        query.setParameter("rivername", riverName);
+        return query.list();
+    }
+
+
+    /**
+     * True if the given section is the "newest" for that river.
+     * @param section Given section
+     * @return true if the section has the most advanced end of its validity interval
+     *         or the most advanced start of its validity interval.
+     */
+    public static boolean isNewest(CrossSection section) {
+        Session session = SessionHolder.HOLDER.get();
+        Query query = session.createQuery(
+            "from CrossSection where river.id = :riverid "
+            + " order by timeInterval.stopTime desc, timeInterval.startTime desc");
+        query.setParameter("riverid", section.getRiver().getId());
+
+        List result = query.list();
+
+        if (result == null || result.isEmpty()) {
+            return true;
+        }
+        else {
+            CrossSection cs = (CrossSection) result.get(0);
+            return section.getId().equals(cs.getId());
+        }
+    }
+
+
+    /**
+     *  Get a specific CrossSection from db.
+     *  @param id The dbid of the cross-section to load.
+     */
+    public static CrossSection getCrossSection(int id) {
+        Cache cache = CacheFactory.getCache(CACHE_NAME);
+        if (cache != null) {
+            Element element = cache.get(Integer.valueOf(id));
+            if (element != null) {
+                return (CrossSection) element.getValue();
+            }
+        }
+
+        CrossSection section = getCrossSectionUncached(id);
+        if (cache != null) {
+            Element element = new Element(Integer.valueOf(id), section);
+            cache.put(element);
+        }
+
+        return section;
+    }
+
+
+    /** Get specific CrossSection from database. */
+    protected static CrossSection getCrossSectionUncached(int id) {
+        Session session = SessionHolder.HOLDER.get();
+        Query query = session.createQuery(
+                "from CrossSection where id=:id");
+        query.setParameter("id", id);
+        List<CrossSection> list = query.list();
+        return list.isEmpty() ? null : list.get(0);
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf-8 :