--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/flys-artifacts/src/main/java/de/intevation/flys/artifacts/model/LocationProvider.java	Fri Sep 28 12:14:56 2012 +0200
@@ -0,0 +1,89 @@
+package de.intevation.flys.artifacts.model;
+
+import net.sf.ehcache.Cache;
+import net.sf.ehcache.Element;
+
+import org.apache.log4j.Logger;
+
+import de.intevation.flys.model.Annotation;
+import de.intevation.flys.model.Position;
+
+import de.intevation.flys.artifacts.cache.CacheFactory;
+import de.intevation.flys.artifacts.model.AnnotationsFactory;
+
+
+public class LocationProvider {
+
+    public static final String CACHE_KEY = "location-provider";
+
+
+    private static final Logger logger =
+        Logger.getLogger(LocationProvider.class);
+
+
+    private LocationProvider() {
+    }
+
+
+    public static String getLocation(String river, double km) {
+        return getLocation(getLocationHash(river, km), river, km);
+    }
+
+
+    public static String getLocation(String hash, String river, double km) {
+        logger.debug("Fetch location for '" + river + "' at '" + km + "'");
+
+        Cache cache = CacheFactory.getCache(CACHE_KEY);
+
+        if (cache != null) {
+            return getCachedLocation(cache, hash, river, km);
+        }
+        else {
+            logger.info("No Cache for Locations configured.");
+            return getUncachedLocation(river, km);
+        }
+    }
+
+
+    protected static String getCachedLocation(
+        Cache cache,
+        String hash,
+        String river,
+        double km
+    ) {
+        logger.debug("Fetch location from cache.");
+
+        Element element = cache.get(hash);
+
+        if (element == null) {
+            logger.debug("Element is not in cache yet.");
+
+            String location = getUncachedLocation(river, km);
+            element = new Element(hash, location);
+            cache.put(element);
+        }
+
+        return (String) element.getValue();
+    }
+
+
+    protected static String getUncachedLocation(String river, double km) {
+        logger.debug("Fetch location from backend.");
+
+        Annotation annotation = AnnotationsFactory.getAnnotation(river, km);
+
+        if (annotation != null) {
+            logger.debug("Found an annotation.");
+            Position pos = annotation.getPosition();
+            return pos.getValue();
+        }
+
+        return "";
+    }
+
+
+    protected static String getLocationHash(String river, double km) {
+        return river + "#" + km;
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :