使用 Hazelcast SQL 查询 IMap 数据：一种轻量级任务管理方案

import java.io.Serializable;
import java.util.Date;

public class DelayedTask implements Serializable {
    private Long id;
    private String type;
    private String action;
    private Integer retries;
    private String params;
    private Boolean actionRequired;
    private Boolean isCurrentlyRunning;
    private Date penaltyDate;
    private Date insertDate;

    // 省略 getter 和 setter 方法

    public DelayedTask(Long id, String type, String action, Integer retries, String params, Boolean actionRequired, Boolean isCurrentlyRunning, Date penaltyDate, Date insertDate) {
        this.id = id;
        this.type = type;
        this.action = action;
        this.retries = retries;
        this.params = params;
        this.actionRequired = actionRequired;
        this.isCurrentlyRunning = isCurrentlyRunning;
        this.penaltyDate = penaltyDate;
        this.insertDate = insertDate;
    }

    public DelayedTask() {

    }
}

import com.hazelcast.core.Hazelcast;
import com.hazelcast.core.HazelcastInstance;
import com.hazelcast.map.IMap;

public class HazelcastClient {

    public static void main(String[] args) {
        HazelcastInstance hazelcastInstance = Hazelcast.newHazelcastInstance();
        IMap<Long, DelayedTask> delayedTasksMap = hazelcastInstance.getMap("delayed_tasks");

        // 添加一些示例数据
        delayedTasksMap.put(1L, new DelayedTask(1L, "type1", "action1", 0, "params1", true, false, null, new Date()));
        delayedTasksMap.put(2L, new DelayedTask(2L, "type2", "action2", 1, "params2", true, false, null, new Date()));
        delayedTasksMap.put(3L, new DelayedTask(3L, "type3", "action3", 2, "params3", false, false, null, new Date()));

        // 关闭 Hazelcast 实例
        //hazelcastInstance.shutdown();
    }
}

import com.hazelcast.core.Hazelcast;
import com.hazelcast.core.HazelcastInstance;
import com.hazelcast.map.IMap;
import com.hazelcast.sql.SqlResult;
import com.hazelcast.sql.SqlRow;
import com.hazelcast.sql.SqlService;

import java.util.Date;

public class HazelcastSQLClient {

    public static void main(String[] args) {
        HazelcastInstance hazelcastInstance = Hazelcast.newHazelcastInstance();
        SqlService sqlService = hazelcastInstance.getSql();

        String sql = "SELECT __key, id, type, action, retries, params FROM delayed_tasks WHERE actionRequired = true and isCurrentlyRunning = false and (penaltyDate IS NULL or penaltyDate < NOW()) ORDER BY insertDate ASC LIMIT 1";

        try (SqlResult result = sqlService.execute(sql)) {
            for (SqlRow row : result) {
                Long key = row.getObject("__key");
                Long id = row.getObject("id");
                String type = row.getObject("type");
                String action = row.getObject("action");
                Integer retries = row.getObject("retries");
                String params = row.getObject("params");

                System.out.println("Key: " + key + ", ID: " + id + ", Type: " + type + ", Action: " + action + ", Retries: " + retries + ", Params: " + params);
            }
        }

        // 关闭 Hazelcast 实例
        //hazelcastInstance.shutdown();
    }
}