--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/artifacts/src/main/java/de/intevation/artifacts/DataProvider.java	Wed Nov 30 08:20:15 2011 +0000
@@ -0,0 +1,23 @@
+package de.intevation.artifacts;
+
+import de.intevation.artifacts.CallContext;
+
+/**
+ * DataProviders register on a Blackboard with a key (basically shouting
+ * "I can or know X!").
+ *
+ * Consumers look at the blackboard and then consume data from these
+ * DataProvider, passing them (optional) parameterization and the blackboard
+ * itself.
+ *
+ * Through the blackboard-passing-when-consuming, also recursive patterns can
+ * be modelled (but take care, there is no in-built cycle detection).
+ */
+public interface DataProvider {
+    /** Register this DataProvider on a blackboard under a key. */
+    public void register(CallContext blackboard);
+
+    /** Provide data, given parameterization and a "blackboard". */
+    public Object provideData(Object key, Object param, CallContext context);
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :