package org.jpwh.model.advanced;

 import java.io.Serializable;

 import java.math.BigDecimal;

 import java.util.Currency;

 /*

    This value-typed class should be <code>java.io.Serializable</code>: When Hibernate stores entity

    instance data in the shared second-level cache (see <a href="#Caching"/>), it <em>disassembles</em>

    the entity's state. If an entity has a <code>MonetaryAmount</code> property, the serialized

    representation of the property value will be stored in the second-level cache region. When entity

    data is retrieved from the cache region, the property value will be deserialized and reassembled.

  */

 public class MonetaryAmount implements Serializable {

     /*

  The class does not need a special constructor, you can make it immutable, even with

         <code>final</code> fields, as your code will be the only place an instance is created.

      */

     protected final BigDecimal value;

     protected final Currency currency;

     public MonetaryAmount(BigDecimal value, Currency currency) {

         this.value = value;

         this.currency = currency;

     }

     public BigDecimal getValue() {

         return value;

     }

     public Currency getCurrency() {

         return currency;

     }

     /*

  You should implement the <code>equals()</code> and <code>hashCode()</code>

         methods, and compare monetary amounts "by value".

      */

     public boolean equals(Object o) {

         if (this == o) return true;

         if (!(o instanceof MonetaryAmount)) return false;

         final MonetaryAmount monetaryAmount = (MonetaryAmount) o;

         if (!value.equals(monetaryAmount.value)) return false;

         if (!currency.equals(monetaryAmount.currency)) return false;

         return true;

     }

     public int hashCode() {

         int result;

         result = value.hashCode();

         result = 29 * result + currency.hashCode();

         return result;

     }

     /*

  You will need a <code>String</code> representation of a monetary

         amount. Implement the <code>toString()</code> method and a static method to

         create an instance from a <code>String</code>.

      */

     public String toString() {

         return getValue() + " " + getCurrency();

     }

     public static MonetaryAmount fromString(String s) {

         String[] split = s.split(" ");

         return new MonetaryAmount(

             new BigDecimal(split[0]),

             Currency.getInstance(split[1])

         );

     }

 }

 package org.jpwh.converter;

 import org.jpwh.model.advanced.MonetaryAmount;

 import javax.persistence.AttributeConverter;

 import javax.persistence.Converter;

 @Converter(autoApply = true) // Default for MonetaryAmount properties

 public class MonetaryAmountConverter

     implements AttributeConverter<MonetaryAmount, String> {

     @Override

     public String convertToDatabaseColumn(MonetaryAmount monetaryAmount) {

         return monetaryAmount.toString();

     }

     @Override

     public MonetaryAmount convertToEntityAttribute(String s) {

         return MonetaryAmount.fromString(s);

     }

 }

 package org.jpwh.model.advanced.converter;

 import org.jpwh.converter.MonetaryAmountConverter;

 import org.jpwh.model.advanced.MonetaryAmount;

 import javax.persistence.Column;

 import javax.persistence.Convert;

 import javax.persistence.Entity;

 import javax.persistence.GeneratedValue;

 import javax.persistence.Id;

 import javax.validation.constraints.NotNull;

 import java.util.Date;

 @Entity

 public class Item {

     @Id

     @GeneratedValue(generator = "ID_GENERATOR")

     protected Long id;

     @NotNull

     protected String name;

     @NotNull

     @Convert( // Optional, autoApply is enabled

         converter = MonetaryAmountConverter.class,

         disableConversion = false)

     @Column(name = "PRICE", length = 63)

     protected MonetaryAmount buyNowPrice;

     @NotNull

     protected Date createdOn = new Date();

     public Long getId() {

         return id;

     }

     public String getName() {

         return name;

     }

     public void setName(String name) {

         this.name = name;

     }

     public MonetaryAmount getBuyNowPrice() {

         return buyNowPrice;

     }

     public void setBuyNowPrice(MonetaryAmount buyNowPrice) {

         this.buyNowPrice = buyNowPrice;

     }

     // ...

 }

 package org.jpwh.model.advanced.converter;

 abstract public class Zipcode {

     protected String value;

     public Zipcode(String value) {

         this.value = value;

     }

     public String getValue() {

         return value;

     }

     @Override

     public boolean equals(Object o) {

         if (this == o) return true;

         if (o == null || getClass() != o.getClass()) return false;

         Zipcode zipcode = (Zipcode) o;

         return value.equals(zipcode.value);

     }

     @Override

     public int hashCode() {

         return value.hashCode();

     }

 }

 package org.jpwh.converter;

 import org.jpwh.model.advanced.converter.GermanZipcode;

 import org.jpwh.model.advanced.converter.SwissZipcode;

 import org.jpwh.model.advanced.converter.Zipcode;

 import javax.persistence.AttributeConverter;

 import javax.persistence.Converter;

 @Converter

 public class ZipcodeConverter

     implements AttributeConverter<Zipcode, String> {

     @Override

     public String convertToDatabaseColumn(Zipcode attribute) {

         return attribute.getValue();

     }

     @Override

     public Zipcode convertToEntityAttribute(String s) {

         if (s.length() == 5)

             return new GermanZipcode(s);

         else if (s.length() == 4)

             return new SwissZipcode(s);

         // If you get to this point, you should consider

         // cleaning up your database... or you can create

         // an InvalidZipCode subclass and return it here.

         throw new IllegalArgumentException(

             "Unsupported zipcode in database: " + s

         );

     }

 }

 package org.jpwh.model.advanced.converter;

 public class GermanZipcode extends Zipcode {

     public GermanZipcode(String value) {

         super(value);

     }

 }

 package org.jpwh.model.advanced.converter;

 public class SwissZipcode extends Zipcode {

     public SwissZipcode(String value) {

         super(value);

     }

 }

 package org.jpwh.model.advanced.converter;

 import org.jpwh.converter.ZipcodeConverter;

 import org.jpwh.model.Constants;

 import javax.persistence.Convert;

 import javax.persistence.Entity;

 import javax.persistence.GeneratedValue;

 import javax.persistence.Id;

 import javax.persistence.Table;

 import javax.validation.constraints.NotNull;

 import java.io.Serializable;

 @Entity

 @Table(name = "USERS")

 public class User implements Serializable {

     @Id

     @GeneratedValue(generator = Constants.ID_GENERATOR)

     protected Long id;

     @NotNull

     protected String username;

     // Group multiple attribute conversions with @Converts

     @Convert(

         converter = ZipcodeConverter.class,

         attributeName = "zipcode" // Or "city.zipcode" for nested embeddables

     )

     protected Address homeAddress;

     public Long getId() {

         return id;

     }

     public String getUsername() {

         return username;

     }

     public void setUsername(String username) {

         this.username = username;

     }

     public Address getHomeAddress() {

         return homeAddress;

     }

     public void setHomeAddress(Address homeAddress) {

         this.homeAddress = homeAddress;

     }

     // ...

 }

 package org.jpwh.model.advanced.converter;

 import javax.persistence.Column;

 import javax.persistence.Embeddable;

 import javax.validation.constraints.NotNull;

 @Embeddable

 public class Address {

     @NotNull

     @Column(nullable = false)

     protected String street;

     @NotNull

     @Column(nullable = false, length = 5)

     protected Zipcode zipcode;

     @NotNull

     @Column(nullable = false)

     protected String city;

     protected Address() {

     }

     public Address(String street, Zipcode zipcode, String city) {

         this.street = street;

         this.zipcode = zipcode;

         this.city = city;

     }

     public String getStreet() {

         return street;

     }

     public void setStreet(String street) {

         this.street = street;

     }

     public Zipcode getZipcode() {

         return zipcode;

     }

     public void setZipcode(Zipcode zipcode) {

         this.zipcode = zipcode;

     }

     public String getCity() {

         return city;

     }

     public void setCity(String city) {

         this.city = city;

     }

 }