--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/flys-backend/src/main/java/org/dive4elements/river/importer/ImportEdge.java	Thu Apr 25 11:53:11 2013 +0200
@@ -0,0 +1,75 @@
+package de.intevation.flys.importer;
+
+import de.intevation.flys.model.Edge;
+
+import org.hibernate.Session;
+import org.hibernate.Query;
+
+import java.util.List;
+
+import java.math.BigDecimal;
+
+public class ImportEdge
+implements   Comparable<ImportEdge>
+{
+    protected BigDecimal top;
+    protected BigDecimal bottom;
+
+    protected Edge peer;
+
+    public ImportEdge() {
+    }
+
+    public ImportEdge(BigDecimal top, BigDecimal bottom) {
+        this.top    = top;
+        this.bottom = bottom;
+    }
+
+    public BigDecimal getTop() {
+        return top;
+    }
+
+    public void setTop(BigDecimal top) {
+        this.top = top;
+    }
+
+    public BigDecimal getBottom() {
+        return bottom;
+    }
+
+    public void setBottom(BigDecimal bottom) {
+        this.bottom = bottom;
+    }
+
+    private static final int compare(BigDecimal a, BigDecimal b) {
+        if (a == null && b != null) return -1;
+        if (a != null && b == null) return +1;
+        if (a == null && b == null) return  0;
+        return a.compareTo(b);
+    }
+
+    public int compareTo(ImportEdge other) {
+        int cmp = compare(top, other.top);
+        return cmp != 0 ? cmp : compare(bottom, other.bottom);
+    }
+
+    public Edge getPeer() {
+        if (peer == null) {
+            Session session = ImporterSession.getInstance().getDatabaseSession();
+            Query query = session.createQuery(
+                "from Edge where top=:top and bottom=:bottom");
+            query.setParameter("top", top);
+            query.setParameter("bottom", bottom);
+            List<Edge> edges = query.list();
+            if (edges.isEmpty()) {
+                peer = new Edge(top, bottom);
+                session.save(peer);
+            }
+            else {
+                peer = edges.get(0);
+            }
+        }
+        return peer;
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :