--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gwt-client/src/main/java/org/dive4elements/river/client/server/RiverServiceImpl.java	Thu Apr 25 15:23:37 2013 +0200
@@ -0,0 +1,104 @@
+package org.dive4elements.river.client.server;
+
+import org.dive4elements.artifacts.common.ArtifactNamespaceContext;
+import org.dive4elements.artifacts.common.utils.XMLUtils;
+import org.dive4elements.artifacts.httpclient.exceptions.ConnectionException;
+import org.dive4elements.artifacts.httpclient.http.HttpClient;
+import org.dive4elements.artifacts.httpclient.http.HttpClientImpl;
+import org.dive4elements.river.client.client.services.RiverService;
+import org.dive4elements.river.client.server.auth.User;
+import org.dive4elements.river.client.shared.exceptions.ServerException;
+import org.dive4elements.river.client.shared.model.DefaultRiver;
+import org.dive4elements.river.client.shared.model.River;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import javax.xml.xpath.XPathConstants;
+
+import org.apache.log4j.Logger;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.w3c.dom.NodeList;
+
+
+/**
+ * This interface provides a method to list the supported rivers of the artifact
+ * server.
+ *
+ * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
+ */
+public class RiverServiceImpl
+extends      RemoteServiceServlet
+implements   RiverService
+{
+    /** Private logger. */
+    private static final Logger logger =
+        Logger.getLogger(RiverServiceImpl.class);
+
+    /** The XPath string that points to the rivers in the resulting document.*/
+    public static final String XPATH_RIVERS = "/art:rivers/art:river";
+
+    /** The error message key that is thrown if an error occured while reading
+     * the supported rivers from server.*/
+    public static final String ERROR_NO_RIVERS_FOUND = "error_no_rivers_found";
+
+
+    /** Get river list. */
+    @Override
+    public River[] list(String locale)
+    throws ServerException
+    {
+        String url = getServletContext().getInitParameter("server-url");
+
+        Document doc = XMLUtils.newDocument();
+
+        XMLUtils.ElementCreator ec = new XMLUtils.ElementCreator(
+            doc,
+            ArtifactNamespaceContext.NAMESPACE_URI,
+            ArtifactNamespaceContext.NAMESPACE_PREFIX);
+
+        doc.appendChild(ec.create("action"));
+
+        HttpClient client = new HttpClientImpl(url, locale);
+
+        try {
+            Document res = client.callService(url, "rivers", doc);
+
+            NodeList rivers = (NodeList) XMLUtils.xpath(
+                res,
+                XPATH_RIVERS,
+                XPathConstants.NODESET,
+                ArtifactNamespaceContext.INSTANCE);
+
+            if (rivers == null || rivers.getLength() == 0) {
+                throw new ServerException(ERROR_NO_RIVERS_FOUND);
+            }
+
+            int count = rivers.getLength();
+
+            List<River> theRivers = new ArrayList<River>(count);
+            User user = this.getUser();
+
+            for (int i = 0; i < count; i++) {
+                Element tmp = (Element)rivers.item(i);
+
+                String name = tmp.getAttributeNS(
+                    ArtifactNamespaceContext.NAMESPACE_URI, "name");
+
+                if (name.length() > 0
+                && (user == null || user.canUseFeature("river:" + name))) {
+                    theRivers.add(new DefaultRiver(name));
+                }
+            }
+
+            return theRivers.toArray(new River[theRivers.size()]);
+        }
+        catch (ConnectionException ce) {
+            logger.error(ce, ce);
+        }
+
+        throw new ServerException(ERROR_NO_RIVERS_FOUND);
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :