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设计模式--简单工厂模式代码详解

设计模式--简单工厂模式代码详解

作者: 进击的三文鱼 | 来源:发表于2019-05-17 16:05 被阅读5次

    项目中要实现一个功能,功能具体为,选择不同的邮件名称,产生不同的邮件模板。
    功能图例


    image.png

    实现思路上,想到了通过简单工厂模式,简单工厂模式只关心产出的产品不关心实现过程,只需要传入一个类型吗,就能得到想要的结果,十分符合开闭原则。

    下面是该功能的UML类图


    image.png

    首先,定义一个抽象的父类 IShMessageEmailService
    然后定义实现类 ShMessageEmailEtaService 及 ShMessageEmailEtdService
    最后定义工厂类 ShipMessageEmailFactory 工厂类接受一个类型码参数,用来判定产生哪个产品。

    代码如下

    public interface IShMessageEmailService {
        public String getMessageText(ShDynamic dynamic, SailingSchedule sailingSchedule, String messageType);
    }
    
    
    @Service
    public class ShMessageEmailEtaService extends BusinessService implements IShMessageEmailService {
    
        @Autowired
        private ShManifestCargoService shManifestCargoService;
        @Autowired
        private ShipPortService shipPortService;
    
        @Override
        public String getMessageText(ShDynamic dynamic, SailingSchedule sailingSchedule, String messageType) {
            ShManifestCargo shManifestCargo = shManifestCargoService.findImpCargoAndBlNo(sailingSchedule.getId());
            String loadPortCode = "";
            String loadPortName = "";
            String dischargePortCode = "";
            String dischargePortName = "";
            String loadPortCnName = "";
            String dischargePortCnName = "";
            String cargoDesc = "";
            String blNo = "";
            BigDecimal grossWeight = new BigDecimal(0);
            if (shManifestCargo != null) {
                if (shManifestCargo.getCargoDesc() != null) {
                    cargoDesc = shManifestCargo.getCargoDesc();
                }
            }
            //装货港
            if (shManifestCargo != null) {
                blNo = shManifestCargo.getBlNo();
                if (shManifestCargo.getGrossWeight() != null) {
                    grossWeight = shManifestCargo.getGrossWeight();
                }
                loadPortCode = shManifestCargo.getLoadPortCode();
                dischargePortCode = shManifestCargo.getDischargePortCode();
                if (loadPortCode != null) {
                    ShipPort shipPort = shipPortService.findByPortCode(loadPortCode);
                    loadPortName = shipPort.getName();
                    if (shipPort.getCountryCode() != null) {
                        loadPortCnName = shipPort.getCountryCode();
                    }
                }
                if (dischargePortCode != null) {
                    ShipPort shipPort = shipPortService.findByPortCode(dischargePortCode);
                    dischargePortName = shipPort.getName();
                    if (shipPort.getCountryCode() != null) {
                        dischargePortCnName = shipPort.getCountryCode();
                    }
                }
            }
            StringBuilder sb = new StringBuilder();
            sb.append("Dear " + (sailingSchedule.getFirstClientName() == null ? "" : sailingSchedule.getFirstClientName()) + "\n");
            sb.append("\n");
            sb.append("Mt. Morning Calm " + sailingSchedule.getShipEnName() + "\n");
            sb.append("=== Cargo: " + cargoDesc + "=== \n");
    
            if ("".equals(loadPortCode) || "".equals(loadPortCnName)) {
                sb.append("Port of Loading: " + loadPortName + loadPortCnName + "\n");
            } else {
                sb.append("Port of Loading: " + loadPortName + "," + loadPortCnName + "\n");
            }
            if ("".equals(dischargePortCode) || "".equals(dischargePortCnName)) {
                sb.append("Port of Discharging: " + dischargePortName + dischargePortCnName + "\n");
            } else {
                sb.append("Port of Discharging: " + dischargePortName + "," + dischargePortCnName + "\n");
            }
            if ("".equals(blNo)) {
                if (grossWeight.compareTo(new BigDecimal(0)) == 0) {
                    sb.append("B/L Quantity: \n");
    
                } else {
                    sb.append("B/L Quantity:" + grossWeight + "KGS\n");
                }
            } else {
                if (grossWeight.compareTo(new BigDecimal(0)) == 0) {
                    sb.append("B/L Quantity:" + blNo + "\n");
    
                } else {
                    sb.append("B/L Quantity:" + blNo + "," + grossWeight + "KGS\n");
                }
            }
            sb.append("\n");
            sb.append("--/-/-   Arrived Guishan p/stn\n");
            sb.append("--/-/-   Dropped anchor & NOR tendered\n");
            sb.append("--/-/-   POB\n");
            // 靠泊时间
            sb.append("--/-/-   First line ashored\n");
            // ALL FAST
            sb.append("--/-/-   All line fasted at wharf No.4\n");
            // 开始联检时间
            sb.append("--/-/-   Free pratique granted\n");
            // 开工时间
            sb.append("--/-/-   Estimated time of discharging commence\n");
            // 预计完工时间
            sb.append("--/-/-   Estimated time of discharging complete\n");
            // 预计离泊时间
            sb.append("--/-/-   ETD (Subject to discharging & Main Channel traffic control) \n");
            sb.append("\n");
            sb.append("Arrival conditions:\n");
            // 抵港油水FO DO FW
            BigDecimal arrvFo = dynamic.getArrvFo();
            BigDecimal arrvDo = dynamic.getArrvDo();
            BigDecimal arrvFw = dynamic.getArrvFw();
            sb.append("Bunker - FO:" + (arrvFo == null ? "" : arrvFo) + "MTS/DO:" + (arrvDo == null ? "" : arrvDo) + "MTS/FW:" + (arrvFw == null ? "" : arrvFw) + "MTS \n");
            // 抵港吃水F A
            BigDecimal arrvDraughtf = dynamic.getArrvDraughtf();
            BigDecimal arrvDraughta = dynamic.getArrvDraughta();
            sb.append("Draft -  F:" + (arrvDraughtf == null ? "" : arrvDraughtf) + "M/A:" + (arrvDraughta == null ? "" : arrvDraughta) + "M \n");
            sb.append("\n");
            sb.append("Remark:\n");
            sb.append("1.Vessel can (un)berth at Xiaohu terminal only in daytime.\n");
            sb.append("2.Vessel can (un)berth only against ebb tide.\n");
            sb.append("3.Two tugboats assist berthing. \n");
            sb.append("\n");
            sb.append("Thank you for your kind agency appointment.If any inquries pls be free let me know. \n");
            sb.append("We respectfully remind you to also email the relevant information to the operator in charge of this voyage and do not reply this system email. \n");
            return sb.toString();
        }
    }
    
    @Service
    public class ShMessageEmailEtdService extends BusinessService implements IShMessageEmailService {
    
        @Autowired
        private ShManifestCargoService shManifestCargoService;
        @Autowired
        private ShipPortService shipPortService;
    
        @Override
        public String getMessageText(ShDynamic dynamic, SailingSchedule sailingSchedule, String messageType) {
            ShManifestCargo shManifestCargo = shManifestCargoService.findExpCargoAndBlNo(sailingSchedule.getId());
            String loadPortCode = "";
            String loadPortName = "";
            String dischargePortCode = "";
            String dischargePortName = "";
            String loadPortCnName = "";
            String dischargePortCnName = "";
            String cargoDesc = "";
            String blNo = "";
            BigDecimal grossWeight = new BigDecimal(0);
            if(shManifestCargo!=null){
                if(shManifestCargo.getCargoDesc()!=null){
                    cargoDesc = shManifestCargo.getCargoDesc();
                }
            }
    
            //装货港
            if (shManifestCargo!=null) {
                blNo = shManifestCargo.getBlNo();
                if(shManifestCargo.getGrossWeight()!=null){
                    grossWeight = shManifestCargo.getGrossWeight();
                }
                loadPortCode = shManifestCargo.getLoadPortCode();
                dischargePortCode = shManifestCargo.getDischargePortCode();
                if (loadPortCode != null) {
                    ShipPort shipPort = shipPortService.findByPortCode(loadPortCode);
                    loadPortName = shipPort.getName();
                    if(shipPort.getCountryCode()!=null){
                        loadPortCnName = shipPort.getCountryCode();
                    }
                }
                if (dischargePortCode != null) {
                    ShipPort shipPort = shipPortService.findByPortCode(dischargePortCode);
                    dischargePortName = shipPort.getName();
                    if(shipPort.getCountryCode()!=null){
                        dischargePortCnName = shipPort.getCountryCode();
                    }
                }
            }
            StringBuilder sb = new StringBuilder();
            sb.append("Dear " + (sailingSchedule.getFirstClientName() == null ? "" : sailingSchedule.getFirstClientName()) + "\n");
            sb.append("\n");
            sb.append("Mt. Morning Calm " + sailingSchedule.getShipEnName() + "\n");
            sb.append("=== Cargo: " + cargoDesc + "=== \n");
    
            if ("".equals(loadPortCode) || "".equals(loadPortCnName)) {
                sb.append("Port of Loading: " + loadPortName + loadPortCnName + "\n");
            } else {
                sb.append("Port of Loading: " + loadPortName + "," + loadPortCnName + "\n");
            }
            if ("".equals(dischargePortCode) || "".equals(dischargePortCnName)) {
                sb.append("Port of Discharging: " + dischargePortName + dischargePortCnName + "\n");
            } else {
                sb.append("Port of Discharging: " + dischargePortName + "," + dischargePortCnName + "\n");
            }
    //        sb.append("Pls B Advd Abv Vsl's Arriving Conditon Asfs:\n");
            if ("".equals(blNo)) {
                if(grossWeight.compareTo(new BigDecimal(0))==0) {
                    sb.append("B/L Quantity: \n");
    
                }else{
                    sb.append("B/L Quantity:"+ grossWeight + "KGS\n");
                }
            }else{
                if(grossWeight.compareTo(new BigDecimal(0))==0) {
                    sb.append("B/L Quantity:" + blNo + "\n");
    
                }else{
                    sb.append("B/L Quantity:" + blNo + "," + grossWeight + "KGS\n");
                }
            }
            sb.append("\n");
            sb.append("--/-/-   Arrived Guishan p/stn\n");
            sb.append("--/-/-   Dropped anchor & NOR tendered\n");
            sb.append("--/-/-   POB\n");
            // 靠泊时间
            sb.append("--/-/-   First line ashored\n");
            // ALL FAST
            sb.append("--/-/-   All line fasted\n");
            // 开始联检时间
            sb.append("--/-/-   Free pratique granted\n");
            // 开工时间
            sb.append("--/-/-   Hose on\n");
            // 预计完工时间
            sb.append("--/-/-   Discharging commenced\n");
            // 预计离泊时间
            sb.append("--/-/-   Discharging completed \n");
            sb.append("--/-/-   Vapour pushing completed \n");
            sb.append("--/-/-   Hose off \n");
            sb.append("--/-/-   Outbound pilot on board \n");
            sb.append("--/-/-   Sailed from Nansha \n");
            sb.append("--/-/-   ETA Tokuyama \n");
            sb.append("\n");
            sb.append("Arrival conditions:\n");
            // 抵港油水FO DO FW
            BigDecimal arrvFo = dynamic.getArrvFo();
            BigDecimal arrvDo = dynamic.getArrvDo();
            BigDecimal arrvFw = dynamic.getArrvFw();
            sb.append("Bunker - FO:" + (arrvFo == null ? "" : arrvFo) + "MTS/DO:" + (arrvDo == null ? "" : arrvDo) + "MTS/FW:" + (arrvFw == null ? "" : arrvFw) + "MTS\n");
            // 抵港吃水F A
            BigDecimal arrvDraughtf = dynamic.getArrvDraughtf();
            BigDecimal arrvDraughta = dynamic.getArrvDraughta();
            sb.append("Draft -  F:" + (arrvDraughtf == null ? "" : arrvDraughtf) + "M/A:" + (arrvDraughta == null ? "" : arrvDraughta) + "M\n");
            sb.append("\n");
            sb.append("Departure conditions:\n");
    
            // 离港油水FO DO FW
            BigDecimal deptFo = dynamic.getDeptFo();
            BigDecimal deptDo = dynamic.getDeptDo();
            BigDecimal deptFw = dynamic.getDeptFw();
            sb.append("Bunker - FO:" + (deptFo == null ? "" : deptFo) + "MTS/DO:" + (deptDo == null ? "" : deptDo) + "MTS/FW:" + (deptFw == null ? "" : deptFw) + "MTS \n");
            // 离港吃水F A
            BigDecimal deptDraughtf = dynamic.getDeptDraughtf();
            BigDecimal deptDraughta = dynamic.getDeptDraughta();
            sb.append("Draft -  F:" + (deptDraughtf == null ? "" : deptDraughtf) + "M/A:" + (deptDraughta == null ? "" : deptDraughta) + "M \n");
            sb.append("\n");
            sb.append("Remark:\n");
            sb.append("1.Vessel can (un)berth at Xiaohu terminal only in daytime.\n");
            sb.append("2.Vessel can (un)berth only against ebb tide.\n");
            sb.append("3.Two tugboats assist berthing. \n");
            sb.append("4.One tugboat assist unberthing. \n");
            sb.append("\n");
            sb.append("Thanks again for your kind agency appointment.If any inquries pls be free let me know.\n");
            sb.append("We respectfully remind you to also email the relevant information to the operator in charge of this voyage and do not reply this system email. \n");
            return sb.toString();
        }
    }
    
    
    
    @Service
    public class ShipMessageEmailFactory {
        public static final String ETA_MESSAGE = "etaMessage";
        public static final String ETD_MESSAGE = "etdMessage";
        public static final String PROGRESS_MESSAGE = "progressMessage";
        @Autowired
        private ShMessageEmailEtaService shMessageEmailEtaService;
        @Autowired
        private ShMessageEmailEtdService shMessageEmailEtdService;
    
        public IShMessageEmailService createProduct(String messageType) {
            if (messageType.equals(ETA_MESSAGE)) {
                return shMessageEmailEtaService;
            } else if (messageType.equals(ETD_MESSAGE)) {
                return shMessageEmailEtdService;
            }
            return null;
        }
    }
    
    //调用该方法
       @RequestMapping(value = "query_email_model", method = {RequestMethod.GET})
        public SailingQueryEntity queryEmailModel(@RequestParam("id") String id, @RequestParam("messageType") String messageType) {
            SailingQueryEntity entity = new SailingQueryEntity();
            SailingSchedule sailingSchedule = service.find(SailingSchedule.class, id);
            List<ShDynamic> dynamic = shipDynamicService.findBySailingScheduleId(id);
            ShDynamic dynamicEntity = dynamic.get(0);
            String text = "";
            if(!messageType.equals(shipMessageEmailFactory.PROGRESS_MESSAGE)){
                IShMessageEmailService shMessageEmailService = shipMessageEmailFactory.createProduct(messageType);
                text = shMessageEmailService.getMessageText(dynamicEntity, sailingSchedule, messageType);
            }
            entity.setArrivedText(text);
            return entity;
        }
    

    需要注意的是,一般简单工厂模式的工厂类都是使用static进行修饰,即静态方法。但是我在使用static进行修饰时,却报错,原因是,通过spring管理的service不是静态的,而静态方法,要求返回值必须是静态的才行,将static去掉可以了。简单工厂模式很简单,不属于23中设计模式,但是对于软件的拓展性,确是十分重要。

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