content: /**
   * Copyright 1999-2011 Alibaba Group
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
   package com.alibaba.cobar.client.router.rules;
  
  import com.alibaba.cobar.client.router.ICobarRouter;
  
  /**
   * a rule acts in a "when-then" behavior, in our case, when the fact
   * {@link #isDefinedAt(Object)} or matches, then we will return action result.
   * the {@link ICobarRouter} will decide how to use these action result.
   * 
   * @author fujohnwang
   * @since 1.0
   */
  public interface IRoutingRule<F, T> {
      /**
       * @param <F>, the type of the routing fact
       * @param routeFact, the fact to check against
       * @return
       */
      boolean isDefinedAt(F routingFact);
  
      /**
       * if a update or delete will involve multiple data sources, we have to
       * return a group of data sources to use.<br>
       * for rules the matches only one data source, return a set with size==1.<br>
       * 
       * @return
       */
      T action();
  }
  