Fixed issue code.google.com/p/google-gson/issues/detail?id=353 by add…

…ing set method in JsonArray

gson/src/main/java/com/google/gson/JsonArray.java

@@ -70,6 +70,18 @@ public void addAll(JsonArray array) {
     elements.addAll(array.elements);
   }
 
+  /**
+   * Replaces the element at the specified position in this array with the specified element.
+   *   Element can be null.
+   * @param index index of the element to replace
+   * @param element element to be stored at the specified position
+   * @return the element previously at the specified position
+   * @throws IndexOutOfBoundsException if the specified index is outside the array bounds
+   */
+  public void set(int index, JsonElement element) {
+    elements.set(index, element);
+  }
+
   /**
    * Removes the first occurrence of the specified element from this array, if it is present.
    * If the array does not contain the element, it is unchanged.

gson/src/test/java/com/google/gson/JsonArrayTest.java

@@ -68,6 +68,23 @@ public void testRemove() {
     assertTrue(array.contains(a));
   }
 
+  public void testSet() {
+    JsonArray array = new JsonArray();
+    try {
+      array.set(0, new JsonPrimitive(1));
+      fail();
+    } catch (IndexOutOfBoundsException expected) {}
+    JsonPrimitive a = new JsonPrimitive("a");
+    array.add(a);
+    array.set(0, new JsonPrimitive("b"));
+    assertEquals("b", array.get(0).getAsString());
+    array.set(0, null);
+    assertNull(array.get(0));
+    array.set(0, new JsonPrimitive("c"));
+    assertEquals("c", array.get(0).getAsString());
+    assertEquals(1, array.size());
+  }
+
   public void testDeepCopy() {
     JsonArray original = new JsonArray();
     JsonArray firstEntry = new JsonArray();