Add support for expansion of @param lists (OpenFeign#403)

dsyer · adriancole · commit d536ca9ee53d · 2016-07-02T17:41:31.000+08:00
* Add support for expansion of @param lists The existing support for expanders in method parameters is limited to converting a single value. The change applies the expander individually to each item in a collection or array, thus making it useful for multi-valued query parameters, for instance. The old behaviour is preserved because no existing expanders would have been converting collections to strings (probably). * Change Collection to Iterable and add tests * Add test for null conversion to empty string as well * Remove array handling and null handling
diff --git a/core/src/main/java/feign/ReflectiveFeign.java b/core/src/main/java/feign/ReflectiveFeign.java
@@ -202,7 +202,7 @@ public RequestTemplate create(Object[] argv) {
         Object value = argv[entry.getKey()];
         if (value != null) { // Null values are skipped.
           if (indexToExpander.containsKey(i)) {
-            value = indexToExpander.get(i).expand(value);
+            value = expandElements(indexToExpander.get(i), value);
           }
           for (String name : entry.getValue()) {
             varBuilder.put(name, value);
@@ -224,6 +224,23 @@ public RequestTemplate create(Object[] argv) {
       return template;
     }
 
+    private Object expandElements(Expander expander, Object value) {
+      if (value instanceof Iterable) {
+        return expandIterable(expander, (Iterable) value);
+      }
+      return expander.expand(value);
+    }
+
+    private List<String> expandIterable(Expander expander, Iterable value) {
+      List<String> values = new ArrayList<String>();
+      for (Object element : (Iterable) value) {
+        if (element!=null) {
+          values.add(expander.expand(element));
+        }
+      }
+      return values;
+    }
+
     @SuppressWarnings("unchecked")
     private RequestTemplate addHeaderMapHeaders(Object[] argv, RequestTemplate mutable) {
       Map<Object, Object> headerMap = (Map<Object, Object>) argv[metadata.headerMapIndex()];
diff --git a/core/src/test/java/feign/FeignTest.java b/core/src/test/java/feign/FeignTest.java
@@ -217,6 +217,30 @@ public void customExpander() throws Exception {
         .hasPath("/?date=1234");
   }
 
+  @Test
+  public void customExpanderListParam() throws Exception {
+    server.enqueue(new MockResponse());
+
+    TestInterface api = new TestInterfaceBuilder().target("http://localhost:" + server.getPort());
+
+    api.expandList(Arrays.asList(new Date(1234l), new Date(12345l)));
+
+    assertThat(server.takeRequest())
+        .hasPath("/?date=1234&date=12345");
+  }
+
+  @Test
+  public void customExpanderNullParam() throws Exception {
+    server.enqueue(new MockResponse());
+
+    TestInterface api = new TestInterfaceBuilder().target("http://localhost:" + server.getPort());
+
+    api.expandList(Arrays.asList(new Date(1234l), null));
+
+    assertThat(server.takeRequest())
+        .hasPath("/?date=1234");
+  }
+
   @Test
   public void headerMap() throws Exception {
     server.enqueue(new MockResponse());
@@ -656,6 +680,12 @@ void form(
     @RequestLine("POST /?date={date}")
     void expand(@Param(value = "date", expander = DateToMillis.class) Date date);
 
+    @RequestLine("GET /?date={date}")
+    void expandList(@Param(value = "date", expander = DateToMillis.class) List<Date> dates);
+
+    @RequestLine("GET /?date={date}")
+    void expandArray(@Param(value = "date", expander = DateToMillis.class) Date[] dates);
+
     @RequestLine("GET /")
     void headerMap(@HeaderMap Map<String, Object> headerMap);
 
