权重轮询调度算法(Weighted Round-Robin Scheduling)--java版本
由于每台服务器的配置、安装的业务应用等不同，其处理能力会不一样。所以，我们根据服务器的不同处理能力，给每个服务器分配不同的权值，使其能够接受相应权值数的服务请求。
2个java源文件,如下所示：
public interface IProduceStrategy {
public int getPartitionIdForTopic();
}
public class WeightFactorProduceStrategy implements IProduceStrategy {
private int i = -1; //表示上一次选择的服务器
private int cw = 0; //表示当前调度的权值
private int gcd = 0; //当前所有权重的最大公约数 比如 2，4，8 的最大公约数为：2
private int maxWeight;
private List<Integer> weights = null; //作用计算最大公约数
private PartitionWeightRRParameter weightRRParametersDns[] = null;
/**
* 按照轮询调研权重配置，格式如下:partition1:weight,partition2:weight
* @param partConfig
*/
public WeightFactorProduceStrategy(String partConfig) {
validate(partConfig);
this.initWeigthParam(Tools.parseCsvMap(partConfig));
}
private Pattern pattern = Pattern.compile("([\\d+\\:\\d+],?){1,}");
private void validate(String partConfig) {
if (partConfig.length() <= 0)
throw new InvalidPartitonConfigException("partition config is incorrect :" + partConfig);
else if (partConfig.equals(".") || partConfig.equals(".."))
throw new InvalidPartitonConfigException("partition config is incorrect :" + partConfig);
Matcher matcher = pattern.matcher(partConfig);
if(matcher.find()) {
String rexStr = matcher.group();
if (!rexStr.equals(partConfig))
throw new InvalidPartitonConfigException("partition config is incorrect :" + partConfig);
} else {
throw new InvalidPartitonConfigException("partition config is incorrect :" + partConfig);
}
}
/**
* 格式如下:partition1:weight,partition2:weight
* @param csvMap
*/
private void initWeigthParam(Map<String, String> csvMap) {
weightRRParametersDns = new PartitionWeightRRParameter[csvMap.size()];
int numPart = 0;
weights = new ArrayList<Integer>(csvMap.size());
Set<Map.Entry<String, String>> entrySet = csvMap.entrySet();
for(Iterator<Map.Entry<String, String>> its = entrySet.iterator(); its.hasNext(); ) {
Map.Entry<String, String> entry = its.next();
weights.add(Integer.valueOf(entry.getValue()));
weightRRParametersDns[numPart++] = new PartitionWeightRRParameter(Integer.valueOf(entry.getKey()), Integer.valueOf(entry.getValue()));
}
gcd = getGcdByList(weights);
maxWeight = getMaxWeight();
}
/**
* 计算最大公约数
* @param weight_m 权重数
* @param weight_n 权重数
* @return
*/
private int GCD(int weight_m,int weight_n)
{
int temp;
while(weight_n != 0){
if(weight_m < weight_n){
temp = weight_m;
weight_m = weight_n;
weight_n = temp;
}
temp = weight_m - weight_n;
weight_m = weight_n;
weight_n = temp;
}
return weight_m;
}
/**
*
* @param weights 权重列表
* @param startIndex list索引值,起始位置。
* @param nextGcd 传入最大公约数
* @return
*/
private int getGcdByList(List<Integer> weights, int startIndex, int nextGcd) {
if ( weights.size() < 2) {
throw new IllegalArgumentException("At least a number of parameters for 2");
}
if (weights.size() == 2 && startIndex == 0) {
return this.GCD(weights.get(startIndex), weights.get(startIndex + 1));
}
if (startIndex + 1 > weights.size() -1 )
return nextGcd;
int curGcd = nextGcd > 0 ? nextGcd : weights.get(startIndex);
int nextIndex = startIndex + 1;
nextGcd = GCD(curGcd, weights.get(startIndex + 1)); //0,1
return getGcdByList(weights, nextIndex, nextGcd);
}
private int getGcdByList(List<Integer> weights) {
return this.getGcdByList(weights, 0, 0);
}
private int getWeightDns() {
for ( ; ; ) {
i = (i + 1) % weightRRParametersDns.length;
if (i == 0) {
cw = cw - gcd; //表示当前调度的权值
if (cw <= 0) {
cw = maxWeight;
if (cw == 0) {
return 0;
}
}
}
if (weightRRParametersDns[i].getWeight() >= cw ) {
return weightRRParametersDns[i].getPartition();
}
}
}
private int getMaxWeight() {
int max = 0;
for (int i = 0; i< weightRRParametersDns.length;i++) {
if (weightRRParametersDns[i].getWeight() >= max) {
max = weightRRParametersDns[i].getWeight();
}
}
return max;
}
public int getPartitionIdForTopic() {
return this.getWeightDns();
}
/**
* 分区权重参数类
*/
static class PartitionWeightRRParameter {
private int partition;
private int weight;
public PartitionWeightRRParameter(int partition, int weight) {
this.partition = partition;
this.weight = weight;
}
public int getPartition() {
return partition;
}
public int getWeight() {
return weight;
}
}
}
public class WeightFactorProduceStrategyTest {
@Test
public void testGetPartitionIdForTopic() throws Exception {
IProduceStrategy weightFcProStrategy = new WeightFactorProduceStrategy("0:5,1:15,2:20");
for (int i = 0; i < 40; i++) {
// weightFcProStrategy.getPartitionIdForTopic();
System.out.println(weightFcProStrategy.getPartitionIdForTopic());
}
}
}
测试结果如下:
2
2
1
2
1
2
1
0
2
2
1
2
1
2
1
0
2
2
1
2
1
2
1
0
2
2
1
2
1
2
1
0
2
2
1
2
1
2
1
0