#39 Added basic implementation

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

@@ -0,0 +1,121 @@
+package de.rwu.easydrop.api.client;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+import org.json.JSONException;
+import org.json.JSONObject;
+
+import de.rwu.easydrop.api.dto.ProductDTO;
+
+/**
+ * Interface to an Amazon data source.
+ *
+ * @since 0.1.0
+ */
+public final class AmazonProductDataSource implements DataSource {
+    /**
+     * Name of this data source.
+     */
+    private static final String DATA_ORIGIN = "Amazon";
+    /**
+     * Base URL to the Amazon data source.
+     */
+    private String baseUrl;
+    /**
+     * Credential key to authorize acccess.
+     */
+    private String apiKey;
+    /**
+     * Product region parameter required for data access.
+     */
+    private static final String PRODUCT_REGION = "DE";
+    /**
+     * Locale parameter required for data access.
+     */
+    private static final String LOCALE = "de_DE";
+
+    /**
+     * Sets up instance with Base URL and API Key.
+     *
+     * @param newBaseUrl
+     * @param newApiKey
+     */
+    public AmazonProductDataSource(final String newBaseUrl, final String newApiKey) {
+        this.baseUrl = newBaseUrl;
+        this.apiKey = newApiKey;
+    }
+
+    @Override
+    public ProductDTO getProductDTOById(final String productId) {
+        JSONObject offer = null;
+        ProductDTO product = new ProductDTO(productId, DATA_ORIGIN);
+
+        try {
+            URL apiUrl = new URL(
+                    baseUrl
+                            + "/products/2020-08-26/products/"
+                            + productId
+                            + "/offers?productRegion="
+                            + PRODUCT_REGION
+                            + "&locale="
+                            + LOCALE);
+
+            HttpURLConnection connection = (HttpURLConnection) apiUrl.openConnection();
+            connection.setRequestMethod("GET");
+            connection.setRequestProperty("Credential", apiKey);
+
+            int responseCode = connection.getResponseCode();
+            BufferedReader reader;
+            if (responseCode == HttpURLConnection.HTTP_OK) {
+                reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
+            } else {
+                return product;
+            }
+
+            String line;
+            StringBuilder response = new StringBuilder();
+            while ((line = reader.readLine()) != null) {
+                response.append(line);
+            }
+            reader.close();
+
+            offer = new JSONObject(response.toString());
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+        if (offer == null) {
+            return product;
+        }
+
+        try {
+            offer = offer.getJSONObject("featuredOffer");
+
+            product.setDataOrigin(DATA_ORIGIN);
+            product.setAvailable(offer
+                    .getString("availability")
+                    .equals("available"));
+            product.setCurrentPrice(offer
+                    .getJSONObject("price")
+                    .getJSONObject("value")
+                    .getDouble("amount"));
+            product.setDeliveryPrice(offer
+                    .getJSONArray("shippingOptions")
+                    .getJSONObject(0)
+                    .getJSONObject("shippingCost")
+                    .getJSONObject("value")
+                    .getDouble("amount"));
+            product.setMerchant(offer
+                    .getJSONObject("merchant")
+                    .getString("name"));
+        } catch (JSONException e) {
+            return product;
+        }
+
+        return product;
+    }
+}

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

@@ -12,12 +12,5 @@ public interface DataSource {
      * @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);
+    ProductDTO getProductDTOById(String productId);
 }