HostNameIdGenerator.java

/*
 * Copyright 1999-2015 dangdang.com.
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * </p>
 */

package com.dangdang.ddframe.rdb.sharding.id.generator.self;

import com.dangdang.ddframe.rdb.sharding.id.generator.IdGenerator;

import java.net.InetAddress;
import java.net.UnknownHostException;

/**
 * 根据机器名最后的数字编号获取工作进程Id.如果线上机器命名有统一规范,建议使用此种方式.
 * 列如机器的HostName为:dangdang-db-sharding-dev-01(公司名-部门名-服务名-环境名-编号)
 * ,会截取HostName最后的编号01作为workerId.
 *
 * @author DonneyYoung
 **/
public class HostNameIdGenerator implements IdGenerator {

    private final CommonSelfIdGenerator commonSelfIdGenerator = new CommonSelfIdGenerator();

    static {
        initWorkerId();
    }

    static void initWorkerId() {
        InetAddress address;
        Long workerId;
        try {
            address = InetAddress.getLocalHost();
        } catch (final UnknownHostException e) {
            throw new IllegalStateException("Cannot get LocalHost InetAddress, please check your network!");
        }
        String hostName = address.getHostName();
        try {
            workerId = Long.valueOf(hostName.replace(hostName.replaceAll("\\d+$", ""), ""));
        } catch (final NumberFormatException e) {
            throw new IllegalArgumentException(String.format("Wrong hostname:%s, hostname must be end with number!", hostName));
        }
        CommonSelfIdGenerator.setWorkerId(workerId);
    }

    @Override
    public Number generateId() {
        return commonSelfIdGenerator.generateId();
    }
}