遞歸計算公共生效時間範圍

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

/**
 * @author youfyu
 * @date 2020/06/23
 */

public class Main {
    /**
     *
     */
    public static class Contract {
        /**
         * 公司名
         */
        private String companyName;
        /**
         * 全部子
         */
        private List<Contract> contracts;

        /**
         * 生效時間
         */
        private Date startDate;

        /**
         * 失效時間
         */
        private Date endDate;

        public String getCompanyName() {
            return companyName;
        }

        public void setCompanyName(String companyName) {
            this.companyName = companyName;
        }

        public List<Contract> getContracts() {
            return contracts;
        }

        public void setContracts(List<Contract> contracts) {
            this.contracts = contracts;
        }

        public Date getStartDate() {
            return startDate;
        }

        public void setStartDate(Date startDate) {
            this.startDate = startDate;
        }

        public Date getEndDate() {
            return endDate;
        }

        public void setEndDate(Date endDate) {
            this.endDate = endDate;
        }
    }

    public static class EffectiveTimeRange {
        /**
         *
         */
        Date latestStartDate;
        /**
         *
         */
        Date earliestEndDate;

        public Date getLatestStartDate() {
            return latestStartDate;
        }

        public void setLatestStartDate(Date latestStartDate) {
            this.latestStartDate = latestStartDate;
        }

        public Date getEarliestEndDate() {
            return earliestEndDate;
        }

        public void setEarliestEndDate(Date earliestEndDate) {
            this.earliestEndDate = earliestEndDate;
        }
    }
    //測試
    public static void main(String[] args) throws ParseException {
        String d1 = "2019-6-1 1:10:10";
        String d2 = "2020-6-1 1:10:10";
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

        // 調用parse()方法，將字符串轉換爲日期
        Date date1 = sdf.parse(d1);
        Date date2 = sdf.parse(d2);

        List<Contract> list = new ArrayList<>();
        Contract contract = new Contract();
        contract.setCompanyName("a");
        contract.setEndDate(date1);
        contract.setStartDate(date2);
        List<Contract> list1 = new ArrayList<>();
        list.add(contract);

        Contract contract1 = new Contract();
        contract1.setCompanyName("a");
        contract1.setEndDate(date1);
        contract1.setStartDate(date2);
        list1.add(contract1);
        contract.setContracts(list1);
        EffectiveTimeRange effective = getRelatedEffectiveTimeRange(contract, "a");
        if (effective == null) {
            System.out.println("重合時間不存在");
        } else {
            System.out.println("開始時間：" + effective.getEarliestEndDate());
            System.out.println("結束時間：" + effective.getLatestStartDate());
        }
    }

    /**
     * @param contract    主信息
     * @param companyName 公司名
     * @return 獲取時間範圍
     */
    public static EffectiveTimeRange getRelatedEffectiveTimeRange(Contract contract, String companyName) {
        // 待實現邏輯
        try {
            List<Contract> list = contractDisplay(contract);
            List<EffectiveTimeRange> listTime = new ArrayList<>();
            for (int i = 0; i < list.size() - 1; i++) {
                EffectiveTimeRange effective = getTimeRangeMethod(list.get(i), companyName);
                listTime.add(effective);
            }

            Date startTime = null;
            Date endTime = null;
            if (listTime == null) {
                return null;
            }
            if (listTime.size() > 1) {
                for (int j = 0; j < listTime.size() - 1; j++) {
                    if (listTime.get(j).getEarliestEndDate().after(listTime.get(j + 1).getEarliestEndDate())) {
                        startTime = listTime.get(j).getEarliestEndDate();
                    }
                    if (listTime.get(j).getLatestStartDate().before(listTime.get(j + 1).getLatestStartDate())) {
                        endTime = listTime.get(j).getLatestStartDate();
                    }
                }
            } else if (listTime.size() == 1) {
                startTime = listTime.get(0).getEarliestEndDate();
                endTime = listTime.get(0).getLatestStartDate();
            }

            if (startTime.before(endTime)) {
                EffectiveTimeRange eff = new EffectiveTimeRange();
                eff.setLatestStartDate(startTime);
                eff.setEarliestEndDate(endTime);
                return eff;
            }
        } catch (Exception e) {
            System.out.println(e);
        }
        return null;
    }

    //取當前Contract本層中的時間
    public static EffectiveTimeRange getTimeRangeMethod(Contract contract, String companyName) {
        EffectiveTimeRange effectiveTimeRange = new EffectiveTimeRange();
        if (companyName != null && companyName.equals(contract.getCompanyName())) {
            effectiveTimeRange.setEarliestEndDate(contract.getEndDate());
            effectiveTimeRange.setLatestStartDate(contract.getStartDate());
        }
        return effectiveTimeRange;
    }

    // 遞歸取所有合同
    public static List<Contract> contractDisplay(Contract contract) {
        List<Contract> list = new ArrayList<>();
        if (contract != null && contract.getContracts() != null && contract.getContracts().size() > 0) {
            for (int i = 0; i < contract.getContracts().size(); i++) {
                List<Contract> subList = contractDisplay(contract.getContracts().get(i));
                list.addAll(subList);
            }
        }
        list.add(contract);
        return list;
    }

}