Implement responseFields (#183)

* Query: Implement responseFields

* QueryTest: unit-test responseFields

Author: PLNech

algoliasearch/src/main/java/com/algolia/search/saas/Query.java

@@ -1168,7 +1168,25 @@ public AlternativesAsExact[] getAlternativesAsExact()
         return alternatives;
     }
 
+    private static final String KEY_RESPONSE_FIELDS = "responseFields";
 
+    /**
+     * Choose which fields the response will contain. Applies to search and browse queries.
+     * <p>
+     * By default, all fields are returned. If this parameter is specified, only the fields explicitly listed will be returned, unless * is used, in which case all fields are returned. Specifying an empty list or unknown field names is an error.
+     */
+    public
+    @NonNull
+    Query setResponseFields(String... attributes) {
+        return set(KEY_RESPONSE_FIELDS, buildJSONArray(attributes));
+    }
+
+    /**
+     * Get the fields the response will contain. If unspecified, all fields are returned.
+     */
+    public String[] getResponseFields() {
+        return parseArray(get(KEY_RESPONSE_FIELDS));
+    }
     // ----------------------------------------------------------------------
     // Parsing/serialization
     // ----------------------------------------------------------------------

algoliasearch/src/test/java/com/algolia/search/saas/QueryTest.java

@@ -27,6 +27,8 @@
 import org.json.JSONException;
 import org.junit.Test;
 
+import java.io.UnsupportedEncodingException;
+import java.net.URLEncoder;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -745,4 +747,27 @@ public void test_aroundRadius_all() {
         Query query2 = Query.parse(query.build());
         assertEquals(query2.getAroundRadius(), query.getAroundRadius());
     }
+
+    @Test
+    public void responseFields() throws UnsupportedEncodingException {
+        Query query = new Query();
+        assertNull("A new query should have a null responseFields.", query.getResponseFields());
+        String queryStr = query.build();
+        assertFalse("The built query should not contain responseFields: \"" + queryStr + "\".", queryStr.contains("responseFields"));
+
+        query.setResponseFields("*");
+        assertEquals("After setting its responseFields to \"*\", getResponseFields should contain one element.", 1, query.getResponseFields().length);
+        assertEquals("After setting its responseFields to \"*\", getResponseFields should contain \"*\".", "*", query.getResponseFields()[0]);
+        queryStr = query.build();
+        String expected = "responseFields=" + URLEncoder.encode("[\"*\"]", "UTF-8");
+        assertTrue("The built query should contain \"" + expected + "\", but contains _" + queryStr + "_.", queryStr.contains(expected));
+
+        query.setResponseFields("hits", "page");
+        assertEquals("After setting its responseFields to [\"hits\",\"page\"], getResponseFields should contain two elements.", 2, query.getResponseFields().length);
+        assertEquals("After setting its responseFields to [\"hits\",\"page\"], getResponseFields should contain \"hits\".", "hits", query.getResponseFields()[0]);
+        assertEquals("After setting its responseFields to [\"hits\",\"page\"], getResponseFields should contain \"page\".", "page", query.getResponseFields()[1]);
+        queryStr = query.build();
+        expected = "responseFields=" + URLEncoder.encode("[\"hits\",\"page\"]", "UTF-8");
+        assertTrue("The built query should contain \"" + expected + "\", but contains _" + queryStr + "_.", queryStr.contains(expected));
+    }
 }