com.redismq.rebalance.AllocateMessageQueueAveragely Maven / Gradle / Ivy
package com.redismq.rebalance;
import java.util.ArrayList;
import java.util.List;
/**
* Average Hashing queue algorithm
*/
public class AllocateMessageQueueAveragely implements AllocateMessageQueueStrategy {
@Override
public List allocate(String currentCID, List mqAll,
List cidAll) {
if (currentCID == null || currentCID.length() < 1) {
throw new IllegalArgumentException("currentCID is empty");
}
if (mqAll == null || mqAll.isEmpty()) {
throw new IllegalArgumentException("mqAll is null or mqAll empty");
}
if (cidAll == null || cidAll.isEmpty()) {
throw new IllegalArgumentException("cidAll is null or cidAll empty");
}
List result = new ArrayList<>();
if (!cidAll.contains(currentCID)) {
return result;
}
int index = cidAll.indexOf(currentCID);
int mod = mqAll.size() % cidAll.size();
int averageSize =
mqAll.size() <= cidAll.size() ? 1 : (mod > 0 && index < mod ? mqAll.size() / cidAll.size()
+ 1 : mqAll.size() / cidAll.size());
int startIndex = (mod > 0 && index < mod) ? index * averageSize : index * averageSize + mod;
int range = Math.min(averageSize, mqAll.size() - startIndex);
for (int i = 0; i < range; i++) {
result.add(mqAll.get((startIndex + i) % mqAll.size()));
}
return result;
}
@Override
public String getName() {
return "AVG";
}
}