Spring OrderComparator

  1.     private int doCompare(@Nullable Object o1, @Nullable Object o2, @Nullable OrderSourceProvider sourceProvider) {
  2.         boolean p1 = (o1 instanceof PriorityOrdered);
  3.         boolean p2 = (o2 instanceof PriorityOrdered);
  4.         if (p1 && !p2) {
  5.             return -1;
  6.         } else if (p2 && !p1) {
  7.             return 1;
  8.         }
  10.         int i1 = getOrder(o1, sourceProvider);
  11.         int i2 = getOrder(o2, sourceProvider);
  12.         // 对比两个Order值得大小返回
  13.         return Integer.compare(i1, i2);
  14.     }
  1.     private int getOrder(@Nullable Object obj, @Nullable OrderSourceProvider sourceProvider) {
  2.         Integer order = null;
  3.         if (obj != null && sourceProvider != null) {
  4.             // 获取Order
  5.             Object orderSource = sourceProvider.getOrderSource(obj);
  6.             if (orderSource != null) {
  7.                 if (orderSource.getClass().isArray()) {
  8.                     // 获取 OrderSourceProvider 的值
  9.                     Object[] sources = ObjectUtils.toObjectArray(orderSource);
  10.                     for (Object source : sources) {
  11.                         // 找 order 返回
  12.                         order = findOrder(source);
  13.                         if (order != null) {
  14.                             break;
  15.                         }
  16.                     }
  17.                 } else {
  18.                     // 寻找 order
  19.                     order = findOrder(orderSource);
  20.                 }
  21.             }
  22.         }
  23.         return (order != null ? order : getOrder(obj));
  24.     }
  • 测试用例
  1.     @Test
  2.     public void compareWithSourceProviderArray() {
  3.         Comparator<Object> customComparator = this.comparator.withSourceProvider(
  4.                 new TestSourceProvider(5L, new Object[]{new StubOrdered(10), new StubOrdered(-25)}));
  5.         assertEquals(-1, customComparator.compare(5L, new Object()));
  6.     }

image-20200116141838601

  1.     @Nullable
  2.     protected Integer findOrder(Object obj) {
  3.         // 获取Ordered实现类
  4.         return (obj instanceof Ordered ? ((Ordered) obj).getOrder() : null);
  5.     }
  1.     private static final class StubOrdered implements Ordered {
  3.         private final int order;
  6.         public StubOrdered(int order) {
  7.             this.order = order;
  8.         }
  10.         @Override
  11.         public int getOrder() {
  12.             return this.order;
  13.         }
  14.     }

image-20200116141932486

最终Integer.compare(i1, i2)比较返回 OK !