com.amazonaws.services.simpleworkflow.flow.spring.CronInvocationSchedule Maven / Gradle / Ivy

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The Amazon Web Services SDK for Java provides Java APIs for building software on AWS' cost-effective, scalable, and reliable infrastructure products. The AWS Java SDK allows developers to code against APIs for all of Amazon's infrastructure web services (Amazon S3, Amazon EC2, Amazon SQS, Amazon Relational Database Service, Amazon AutoScaling, etc).

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package com.amazonaws.services.simpleworkflow.flow.spring;

import java.util.Date;
import java.util.TimeZone;

import org.springframework.scheduling.support.CronSequenceGenerator;

import com.amazonaws.services.simpleworkflow.flow.common.FlowConstants;
import com.amazonaws.services.simpleworkflow.flow.interceptors.InvocationSchedule;

public class CronInvocationSchedule implements InvocationSchedule {

    protected static final int SECOND = 1000;

    private final CronSequenceGenerator cronSequenceGenerator;

    private final Date expiration;

    public CronInvocationSchedule(String cronExpression, Date expiration, TimeZone timeZone) {
        cronSequenceGenerator = new CronSequenceGenerator(cronExpression, timeZone);
        this.expiration = expiration;
    }

    @Override
    public long nextInvocationDelaySeconds(Date currentTime, Date startTime, Date lastInvocationTime, int pastInvocatonsCount) {
        Date nextInvocationTime;
        if (lastInvocationTime == null) {
            nextInvocationTime = cronSequenceGenerator.next(startTime);
        }
        else {
            nextInvocationTime = cronSequenceGenerator.next(lastInvocationTime);
        }
        long resultMilliseconds = nextInvocationTime.getTime() - currentTime.getTime();
        if (resultMilliseconds < 0) {
            resultMilliseconds = 0;
        }
        if (currentTime.getTime() + resultMilliseconds >= expiration.getTime()) {
            return FlowConstants.NONE;
        }
        return resultMilliseconds / SECOND;
    }

}