TaskContext.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.job.context;

import com.google.common.base.Function;
import com.google.common.base.Joiner;
import com.google.common.base.Preconditions;
import com.google.common.base.Splitter;
import com.google.common.collect.Lists;
import lombok.EqualsAndHashCode;
import lombok.Getter;
import lombok.RequiredArgsConstructor;
import lombok.Setter;
import lombok.ToString;

import java.util.Collections;
import java.util.List;
import java.util.UUID;

/**
 * 任务运行时上下文.
 *
 * @author zhangliang
 * @author caohao
 */
@Getter
@EqualsAndHashCode(of = "id")
@ToString(of = "id")
public final class TaskContext {
    
    private static final String DELIMITER = "@-@";
    
    private static final String UNASSIGNED_SLAVE_ID = "unassigned-slave";
    
    private String id;
    
    private final MetaInfo metaInfo;
    
    private final ExecutionType type;
    
    private String slaveId;
    
    @Setter
    private boolean idle;
    
    public TaskContext(final String jobName, final List<Integer> shardingItem, final ExecutionType type) {
        this(jobName, shardingItem, type, UNASSIGNED_SLAVE_ID);
    }
    
    public TaskContext(final String jobName, final List<Integer> shardingItem, final ExecutionType type, final String slaveId) {
        metaInfo = new MetaInfo(jobName, shardingItem);
        this.type = type;
        this.slaveId = slaveId;
        id = Joiner.on(DELIMITER).join(metaInfo, type, slaveId, UUID.randomUUID().toString());
    }
    
    private TaskContext(final String id, final MetaInfo metaInfo, final ExecutionType type, final String slaveId) {
        this.id = id;
        this.metaInfo = metaInfo;
        this.type = type;
        this.slaveId = slaveId;
    }
    
    /**
     * 根据任务主键获取任务上下文.
     *
     * @param id 任务主键
     * @return 任务上下文
     */
    public static TaskContext from(final String id) {
        String[] result = id.split(DELIMITER);
        Preconditions.checkState(5 == result.length);
        return new TaskContext(id, MetaInfo.from(result[0] + DELIMITER + result[1]), ExecutionType.valueOf(result[2]), result[3]);
    }
    
    /**
     * 获取未分配执行服务器前的任务主键.
     *
     * @param id 任务主键
     * @return 未分配执行服务器前的任务主键
     */
    public static String getIdForUnassignedSlave(final String id) {
        return id.replaceAll(TaskContext.from(id).getSlaveId(), UNASSIGNED_SLAVE_ID);
    }
    
    /**
     * 设置任务执行服务器主键.
     * 
     * @param slaveId 任务执行服务器主键
     */
    public void setSlaveId(final String slaveId) {
        id = id.replaceAll(this.slaveId, slaveId);
        this.slaveId = slaveId;
    }
    
    /**
     * 获取任务名称.
     *
     * @return 任务名称
     */
    public String getTaskName() {
        return Joiner.on(DELIMITER).join(metaInfo, type, slaveId);
    }
    
    /**
     * 获取任务执行器主键.
     * 
     * @param appName 应用名称
     * @return 任务执行器主键
     */
    public String getExecutorId(final String appName) {
        return Joiner.on(DELIMITER).join(appName, slaveId);
    }
    
    /**
     * 任务元信息.
     */
    @RequiredArgsConstructor
    @Getter
    @EqualsAndHashCode
    public static class MetaInfo {
        
        private final String jobName;
        
        private final List<Integer> shardingItems;
        
        /**
         * 根据任务元信息字符串获取元信息对象.
         *
         * @param value 任务元信息字符串
         * @return 元信息对象
         */
        public static MetaInfo from(final String value) {
            String[] result = value.split(DELIMITER);
            Preconditions.checkState(1 == result.length || 2 == result.length || 5 == result.length);
            return new MetaInfo(result[0], 1 == result.length || "".equals(result[1]) ? Collections.<Integer>emptyList() : Lists.transform(Splitter.on(",").splitToList(result[1]), 
                    new Function<String, Integer>() {
                        
                        @Override
                        public Integer apply(final String input) {
                            return Integer.parseInt(input);
                        }
                    }));
        }
        
        @Override
        public String toString() {
            return Joiner.on(DELIMITER).join(jobName, Joiner.on(",").join(shardingItems));
        }
    }
}