上一篇笔记中更新了在集合中的删除，更新，查询等操作。这次尝试一下SequoiaDB的集群操作。包括复制组的创建和删除，复制组的启动和停止，在复制组中添加、删除、启动、停止节点，获取复制组中的主从节点等。 import java.util.ArrayList;import java.util.L

上一篇笔记中更新了在集合中的删除，更新，查询等操作。这次尝试一下SequoiaDB的集群操作。包括复制组的创建和删除，复制组的启动和停止，在复制组中添加、删除、启动、停止节点，获取复制组中的主从节点等。

import java.util.ArrayList;
import java.util.List;

import org.bson.BSONObject;
import org.bson.BasicBSONObject;

import com.sequoiadb.base.Node.NodeStatus;
import com.sequoiadb.base.DBCursor;
import com.sequoiadb.base.Node;
import com.sequoiadb.base.ReplicaGroup;
import com.sequoiadb.base.Sequoiadb;
import com.sequoiadb.exception.BaseException;

public class BlogRG {


	static String rgName = "testRG";
	static String hostName = "sdbserver1";

	public static void main(String[] args) {

	
	//连接数据库
	String host = "192.168.20.46";
	String port = "11810";
	String usr = "admin";
	String password = "admin";

	Sequoiadb sdb = null;

	try {
	sdb = new Sequoiadb(host + ":" + port, usr, password);
	} catch (BaseException e) {
	e.printStackTrace();
	System.exit(1);
	}
	
	//打印有关复制组信息（名称、个数）
	printGroupInfo(sdb);
	
	//清除环境，删掉重复的复制组
	if(isGroupExist(sdb,rgName)){
	System.out.println("Removing the old replica group...");
	sdb.removeReplicaGroup(rgName);
	}
	
	printGroupInfo(sdb);
	
	//添加新复制组
	System.out.println("Adding the new replica group...");
	ReplicaGroup rg = sdb.createReplicaGroup(rgName);
	
	printGroupInfo(sdb);
	
	//打印复制组内节点信息
	System.out.println("Tere are " + rg.getNodeNum(NodeStatus.SDB_NODE_ALL) + " nodes in the group.");
	
	//添加三个新的节点
	Node node1 = addNode(rg,50000);
	Node node2 = addNode(rg,50010);
	Node node3 = addNode(rg,50020);
	
	//打印复制组内节点信息
	System.out.println("Tere are " + rg.getNodeNum(NodeStatus.SDB_NODE_ALL) + " nodes in the group.");

	//获取复制组的主从节点
	Node master = rg.getMaster();
	System.out.println("The master node is " +master.getPort());
	System.out.println("The slave node is " + rg.getSlave().getPort());
	
	//停止主节点
	System.out.println("stoping the master node...");
	master.stop();
	
	//等待主节点停止
	while(rg.getMaster().getPort() == master.getPort()){
	try{
	Thread.sleep(2000);
	} catch (Exception e){
	}
	}

	//查看新选举的主节点
	System.out.println("re-selecting the master node...");
	System.out.println("The master node is " + rg.getMaster().getPort());
	
	

	}
	

	private static void printGroupInfo(Sequoiadb sdb){
	ArrayList names = sdb.getReplicaGroupNames();
	int count = 0;
	System.out.print("The replica groups are ");
	for (Object name : names){
	count++;
	System.out.print((String)name + ", ");
	}
	System.out.println("\nThere are " + count + " replica groups in total.");
	}
	
	private static boolean isGroupExist(Sequoiadb sdb, String rgName){
	ArrayList names = sdb.getReplicaGroupNames();
	for (Object name : names){
	if(rgName.equals((String)name))
	return true;
	}
	return false;
	}
	
	private static Node addNode(ReplicaGroup rg, int port){
	if(rg.getNode(hostName,port)!= null)
	rg.removeNode(hostName, port, null);
	Node node = rg.createNode(hostName,port,"/opt/sequoiadb/database/test/" + port,null);
	System.out.println("starting the node " + port + "...");
	node.start();
	return node;
	}

}

上面的代码在数据库中添加新的复制组，并在新的复制组内添加三个主节点，数据组自动选举出新的主节点，停止主节点后，复制组内重新选举新的主节点。

运行以上代码后的结果是：

The replica groups are SYSCatalogGroup, datagroup, testRG, 
There are 3 replica groups in total.
Removing the old replica group...
The replica groups are SYSCatalogGroup, datagroup, 
There are 2 replica groups in total.
Adding the new replica group...
The replica groups are SYSCatalogGroup, datagroup, testRG, 
There are 3 replica groups in total.
Tere are 0 nodes in the group.
starting the node 50000...
starting the node 50010...
starting the node 50020...
Tere are 3 nodes in the group.
The master node is 50000
The slave node is 50010
stoping the master node...
re-selecting the master node...
The master node is 50020

运行完成后，通过shell控制台查看数据库testRG复制组的详细情况：

>rg.getDetail()
{
 "Group": [
 {
 "HostName": "sdbserver1",
 "dbpath": "/opt/sequoiadb/database/test/50000",
 "Service": [
 {
 "Type": 0,
 "Name": "50000"
 },
 {
 "Type": 1,
 "Name": "50001"
 },
 {
 "Type": 2,
 "Name": "50002"
 }
 ],
 "NodeID": 1053
 },
 {
 "HostName": "sdbserver1",
 "dbpath": "/opt/sequoiadb/database/test/50010",
 "Service": [
 {
 "Type": 0,
 "Name": "50010"
 },
 {
 "Type": 1,
 "Name": "50011"
 },
 {
 "Type": 2,
 "Name": "50012"
 }
 ],
 "NodeID": 1054
 },
 {
 "HostName": "sdbserver1",
 "dbpath": "/opt/sequoiadb/database/test/50020",
 "Service": [
 {
 "Type": 0,
 "Name": "50020"
 },
 {
 "Type": 1,
 "Name": "50021"
 },
 {
 "Type": 2,
 "Name": "50022"
 }
 ],
 "NodeID": 1055
 }
 ],
 "GroupID": 1023,
 "GroupName": "testRG",
 "PrimaryNode": 1055,
 "Role": 0,
 "Status": 0,
 "Version": 4,
 "_id": {
 "$oid": "53d9d38e14a63a88c621edd8"
 }
}
Return 1 row(s).
Takes 0.4716s.