/*

  * Licensed to the Apache Software Foundation (ASF) under one

  * or more contributor license agreements.  See the NOTICE file

  * distributed with this work for additional information

  * regarding copyright ownership.  The ASF licenses this file

  * to you 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 org.apache.giraph.block_app.framework.api;

 import static com.google.common.base.Preconditions.checkNotNull;

 /**

  * Class that contains references to Block Api objects.

  *

  * One general use-case for this is for applications to indirectly get a handle

  * on the Block Api objects and  implement operations that (i) depend on the

  * Block Api interfaces, (ii) are not in the context of a Piece when defined,

  * and (iii) are in the context of a Piece when executed.

  *

  * To do this, as opposed to defining an application as a

  * {@link org.apache.giraph.block_app.framework.block.Block}, define

  * your application as a

  * {@link org.apache.giraph.block_app.framework.block.BlockWithApiHandle}.

  *

  * NOTE: Depending on the context in which this class is used, some of the

  * handles may not be set. For instance, the {@link masterApi} is not set when

  * this is in the context of a worker. Trying to get access to a handle when

  * it is not set will result in a runtime exception. Instead, you should first

  * use methods like the {@link #isMasterApiSet()} to check.

  *

  * The *Api fields are transient as we do not need/want to serialize them. They

  * will be set at the appropriate time by the framework.

  */

 public class BlockApiHandle {

   private transient BlockMasterApi masterApi;

   private transient BlockWorkerReceiveApi workerReceiveApi;

   private transient BlockWorkerSendApi workerSendApi;

   private transient BlockWorkerContextReceiveApi workerContextReceiveApi;

   private transient BlockWorkerContextSendApi workerContextSendApi;

   public void setMasterApi(BlockMasterApi api) {

     this.masterApi = api;

   }

   public void setWorkerReceiveApi(BlockWorkerReceiveApi api) {

     this.workerReceiveApi = api;

   }

   public void setWorkerSendApi(BlockWorkerSendApi api) {

     this.workerSendApi = api;

   }

   public void setWorkerContextReceiveApi(BlockWorkerContextReceiveApi api) {

     this.workerContextReceiveApi = api;

   }

   public void setWorkerContextSendApi(BlockWorkerContextSendApi api) {

     this.workerContextSendApi = api;

   }

   public boolean isMasterApiSet() {

     return masterApi != null;

   }

   public boolean isWorkerReceiveApiSet() {

     return workerReceiveApi != null;

   }

   public boolean isWorkerSendApiSet() {

     return workerSendApi != null;

   }

   public boolean isWorkerContextReceiveApiSet() {

     return workerContextReceiveApi != null;

   }

   public boolean isWorkerContextSendApiSet() {

     return workerContextSendApi != null;

   }

   public BlockMasterApi getMasterApi() {

     checkNotNull(masterApi,

       "BlockMasterApi not valid in this context.");

     return masterApi;

   }

   public BlockWorkerReceiveApi getWorkerReceiveApi() {

     checkNotNull(workerReceiveApi,

       "BlockWorkerReceiveApi not valid in this context.");

     return workerReceiveApi;

   }

   public BlockWorkerSendApi getWorkerSendApi() {

     checkNotNull(workerSendApi,

       "BlockWorkerSendApi not valid in this context.");

     return workerSendApi;

   }

   public BlockWorkerContextReceiveApi getWorkerContextReceiveApi() {

     checkNotNull(workerContextReceiveApi,

       "BlockWorkerContextReceiveApi not valid in this context");

     return workerContextReceiveApi;

   }

   public BlockWorkerContextSendApi getWorkerContextSendApi() {

     checkNotNull(workerContextSendApi,

       "BlockWorkerContextSendApi not valid in this context");

     return workerContextSendApi;

   }

 }