code: public void checkCompositeFields(String[] names) {
          if (!Lang.isEmptyArray(names) && names.length > 1) {
              for (String name : names) {
                  if (byJava.containsKey(name) && byJava.get(name).isCompositePk())
                      theComposites.add(byJava.get(name));
                  else
                      throw Lang.makeThrow("Fail to find comosite field '%s' in class '%s'!",
                                           name,
                                           type.getName());
              }
              this.pkType = PkType.COMPOSITE;
          } else if (null != this.theId) {
              this.pkType = PkType.ID;
          } else if (null != this.theName) {
              this.pkType = PkType.NAME;
          }
      }
docs: 当所有字段增加完成，这个方法必须被调用，用来搜索复合主键
  
  @param names
  复合主键的 Java 字段名数组