This project has retired. For details please refer to its Attic page.
SendResumeRequest xref
View Javadoc

1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  
19  package org.apache.giraph.comm.requests;
20  
21  import org.apache.giraph.comm.ServerData;
22  import org.apache.giraph.comm.flow_control.CreditBasedFlowControl;
23  import org.apache.giraph.comm.flow_control.FlowControl;
24  
25  import java.io.DataInput;
26  import java.io.DataOutput;
27  import java.io.IOException;
28  
29  import static com.google.common.base.Preconditions.checkState;
30  
31  /**
32   * Send to a worker a signal to resume sending messages to sender worker. This
33   * type of request is used in adaptive credit-based flow control, where a
34   * worker (W) may assign credit value of 0 to some worker (U), so that U would
35   * stop sending messages to W. Later on, W may want to notify U to continue
36   * sending messages to W. Along with the resume signal, W also announces a new
37   * credit value to U.
38   */
39  public class SendResumeRequest extends WritableRequest
40      implements WorkerRequest {
41    /** credit value */
42    private short credit;
43  
44    /** Constructor used for reflection only */
45    public SendResumeRequest() { }
46  
47    /**
48     * Constructor
49     *
50     * @param credit credit value
51     */
52    public SendResumeRequest(short credit) {
53      checkState(credit > 0);
54      this.credit = credit;
55    }
56  
57    @Override
58    public void doRequest(ServerData serverData) {
59      FlowControl flowControl =
60          serverData.getServiceWorker().getWorkerClient().getFlowControl();
61      checkState(flowControl != null);
62      ((CreditBasedFlowControl) flowControl).processResumeSignal(getClientId(),
63          credit, getRequestId());
64    }
65  
66    @Override
67    public RequestType getType() {
68      return RequestType.SEND_RESUME_REQUEST;
69    }
70  
71    @Override
72    void readFieldsRequest(DataInput input) throws IOException {
73      credit = input.readShort();
74    }
75  
76    @Override
77    void writeRequest(DataOutput output) throws IOException {
78      output.writeShort(credit);
79    }
80  }