Added basic outline

src/main/java/de/rwu/easydrop/api/client/DataSource.java

@@ -0,0 +1,23 @@
+package de.rwu.easydrop.api.client;
+
+import de.rwu.easydrop.api.dto.ProductDTO;
+
+/**
+ * Universal interface to implement concrete APIs on.
+ */
+public interface DataSource {
+    /**
+     * Retrieves product info from the data source.
+     *
+     * @param productId Identifier
+     * @return ProductDTO
+     */
+    ProductDTO getProductById(String productId);
+
+    /**
+     * Breaks the connection after specified time.
+     *
+     * @param timeoutSeconds Seconds to time out after
+     */
+    void setConnectionTimeout(int timeoutSeconds);
+}

src/main/java/de/rwu/easydrop/api/client/package-info.java

@@ -0,0 +1,6 @@
+/**
+ * API client connectors for interaction with external data sources.
+ *
+ * @since 0.1.0
+ */
+package de.rwu.easydrop.api.client;