com.github.antelopeframework.mybatis.shard.routing.PartitionRouter Maven / Gradle / Ivy

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package com.github.antelopeframework.mybatis.shard.routing;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;

import lombok.Setter;

/**
 * 数据库分区路由.
 * 
 * @author yangzhi.yzh
 *
 */
public class PartitionRouter implements InitializingBean {
	private Map groupMapping = new HashMap<>();

	@Setter
	@Autowired
	List partitionGroups = new ArrayList<>();
	
	@Override
	public void afterPropertiesSet() throws Exception {
		if (partitionGroups != null) {
			for (PartitionGroup p : partitionGroups) {
				groupMapping.put(p.getName(), p);
			}
		}
	}
	
	/**
	 * 根据pValue (对应 PartitionGroup中的name属性), 获取到最终的分区名称.
	 * 
	 * @param pValue
	 * @return
	 */
	public String getFinalPartitionKey(String pValue) {
		PartitionGroup pGroup = groupMapping.get(pValue);
		if (pGroup == null) {
			throw new IllegalArgumentException("no PartitionGroup with name: " + pValue);
		}
		
		return buildFinalShardKey(pGroup.getName(), 0);
	}
	
	/**
	 * 根据pValue (对应 PartitionGroup中的name属性) 以及 分表参考值, 获取到最终的分区名称. 

	 * 使用的算法为: Math.abs(shardValue.hashCode() % pGroup.size()).
	 * 
	 * @param pValue 
	 * @param shardValue 分表参考值
	 * @return
	 */
	public String getFinalShardKey(String pValue, Object shardValue) {
		PartitionGroup pGroup = groupMapping.get(pValue);
		if (pGroup == null) {
			throw new IllegalArgumentException("no PartitionGroup with name: " + pValue);
		}
		
		return buildFinalShardKey(pGroup.getName(), Math.abs(shardValue.hashCode()) % pGroup.size());
	}
	
	/**
	 * 获取所有的 {@link PartitionGroup}.
	 * 
	 * @return
	 */
	public List getPartitionGroups() {
		return Collections.unmodifiableList(partitionGroups);
	}
	
	/**
	 * 
	 * @param pName {@link PartitionGroup} 的 name 属性.
	 * @param shardIndex 
	 * @return
	 */
	public static String buildFinalShardKey(String pName, int shardIndex) {
		return pName + "::" + shardIndex;
	}

}