PartitionByFileMap.java

/*
 * Copyright (c) 2013, OpenCloudDB/MyCAT and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software;Designed and Developed mainly by many Chinese
 * opensource volunteers. you can redistribute it and/or modify it under the
 * terms of the GNU General Public License version 2 only, as published by the
 * Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Any questions about this component can be directed to it's project Web address
 * https://code.google.com/p/opencloudb/.
 *
 */
package io.mycat.route.function;


import java.util.HashMap;
import java.util.Map;
import java.util.Set;

/**
 *
 * @author mycat
 */
public class PartitionByFileMap extends AbstractPartitionAlgorithm implements RuleAlgorithm {

	private Map<Object, Integer> app2Partition;
	/**
	 * Map<Object, Integer> app2Partition中key值的类型：默认值为0，0表示Integer，非零表示String
	 */
	private int type;

	/**
	 * 默认节点在map中的key
	 */
	private static final String DEFAULT_NODE = "DEFAULT_NODE";

	/**
	 * 默认节点:小于0表示不设置默认节点，大于等于0表示设置默认节点
	 *
	 * 默认节点的作用：枚举分片时，如果碰到不识别的枚举值，就让它路由到默认节点
	 *                如果不配置默认节点（defaultNode值小于0表示不配置默认节点），碰到
	 *                不识别的枚举值就会报错，
	 *                like this：can't find datanode for sharding column:column_name val:ffffffff
	 */
	private int defaultNode = -1;

	@Override
	public void init() {
		initialize();
	}

	public void setType(int type) {
		this.type = type;
	}
	public void setDefaultNode(int defaultNode) {
		this.defaultNode = defaultNode;
	}
	public int getType() {
		return type;
	}
	public int getDefaultNode() {
		return defaultNode;
	}

	@Override
	public Integer calculate(String columnValue) {
		Object value = columnValue;
		if(type == 0) {
			value = Integer.valueOf(columnValue);
		}
		Integer rst = null;
		Integer pid = app2Partition.get(value);
		if (pid != null) {
			rst = pid;
		} else {
			rst =app2Partition.get(DEFAULT_NODE);
		}
		return rst;
	}

	private void initialize() {
		if (this.getConfig().isEmpty()) {
			throw new RuntimeException("can't find enum config, like <config> <property name=\"10000\">0</property><property name=\"10010\">1</property> </config>");
		}
		Set<String> keys = this.getConfig().keySet();
		app2Partition = new HashMap<Object, Integer>();
		for(String key : keys){
			if(type == 0) {
				app2Partition.put(Integer.valueOf(key), Integer.valueOf(String.valueOf(this.getConfig().get(key))));
			}else {
				app2Partition.put(key, Integer.valueOf((String)this.getConfig().get(key)));
			}
		}
		//设置默认节点
		if(defaultNode >= 0) {
			app2Partition.put(DEFAULT_NODE, defaultNode);
		}
	}
}