CSTRequestFGT1.java

/**
Copyright (c) 2007-2013 Alysson Bessani, Eduardo Alchieri, Paulo Sousa, and the authors indicated in the @author tags

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 bftsmart.statemanagement.strategy.durability;

/**
 * This class is used to define the roles in the Collaborative State Transfer protocol.
 * The recovering replica uses this class to define which replicas should send the
 * checkpoint, log of opperations lower and higher portions
 * 
 * @author Marcel Santos
 */
public class CSTRequestFGT1 extends CSTRequest {
	
	private static final long serialVersionUID = 7661647491651173164L;
	
	private int hashesReplica;
	/** number of requests to be processed in the recovering replica before validate the ckp hash */
	private int nbrHashesBeforeCkp;
	
	/** number of messages that should be in the batch
	 * if the replica is the one to send the checkpoint it will correspond to the actual log
	 */
	private int logSize;
	
	public CSTRequestFGT1(int cid) {
		super(cid);
	}
	
	public int getHashesReplica() {
		return hashesReplica;
	}
	public int getNbrHashesBeforeCkp() {
		return nbrHashesBeforeCkp;
	}
	
	public int getLogSize() {
		return logSize;
	}
	
	@Override
	public void defineReplicas(int[] processes, int globalCkpPeriod, int replicaId) {
    	int N = processes.length;
    	int ckpPeriod = globalCkpPeriod / N;
    	int logSize = (cid + 1) % ckpPeriod;
    	
    	// Next replica that performed the checkpoint
    	// The last checkpoint replica plus all replicas minus one to get the imediate replica before the
    	// checkpoint
    	int indexCkpReplica = (((getCID() - ckpPeriod) % globalCkpPeriod) / ckpPeriod) % N;
    	this.hashesReplica = processes[indexCkpReplica];
    	this.checkpointReplica = processes[(indexCkpReplica + (N - 1)) % N];
    	this.nbrHashesBeforeCkp = ckpPeriod;
		logSize += ckpPeriod;
    	if(this.checkpointReplica == replicaId) { // me
        	this.checkpointReplica = processes[(indexCkpReplica + (N - 2)) % N];
        	this.nbrHashesBeforeCkp = 2 * ckpPeriod;
    		logSize += ckpPeriod;
    	} else if(this.hashesReplica == replicaId) {
    		this.hashesReplica = processes[(indexCkpReplica + (N - 1)) % N];
    		this.checkpointReplica = processes[(indexCkpReplica + (N - 2)) % N];
    		logSize += ckpPeriod;
    	}
    	this.logSize = logSize;
    }
}