Adds the domain entities

This commit includes the complete code for the domain entities.

domain/src/main/java/es/uvigo/esei/xcs/domain/entities/AnimalType.java

+package es.uvigo.esei.xcs.domain.entities;
+
+/**
+ * The type of animal.
+ * 
+ * @author Miguel Reboiro-Jato
+ *
+ */
+public enum AnimalType {
+	DOG, CAT, BIRD;
+}

domain/src/main/java/es/uvigo/esei/xcs/domain/entities/Owner.java

+package es.uvigo.esei.xcs.domain.entities;
+
+import static java.util.Arrays.stream;
+import static java.util.Collections.unmodifiableCollection;
+import static java.util.Objects.requireNonNull;
+import static org.apache.commons.lang3.Validate.inclusiveBetween;
+import static org.apache.commons.lang3.Validate.matchesPattern;
+
+import java.io.Serializable;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.util.ArrayList;
+import java.util.Collection;
+
+import javax.persistence.CascadeType;
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.OneToMany;
+import javax.xml.bind.annotation.adapters.HexBinaryAdapter;
+
+/**
+ * A pet owner.
+ * 
+ * @author Miguel Reboiro-Jato
+ */
+@Entity
+public class Owner implements Serializable {
+	private static final long serialVersionUID = 1L;
+
+	@Id
+	@Column(length = 100, nullable = false)
+	private String login;
+	
+	@Column(length = 32, nullable = false)
+	private String password;
+	
+	@OneToMany(mappedBy = "owner", cascade = CascadeType.ALL, orphanRemoval = true)
+	private Collection<Pet> pets;
+	
+	// Required for JPA
+	Owner() {}
+	
+	/**
+	 * Creates a new instance of {@code Owner} without pets.
+	 * 
+	 * @param login the login that identifies the user. This parameter must be a
+	 * non empty and non {@code null} string with a maximum length of 100 chars.
+	 * @param password the raw password of the user. This parameter must be a
+	 * non {@code null} string with a minimum length of 6 chars.
+	 * 
+	 * @throws NullPointerException if a {@code null} value is passed as the
+	 * value for any parameter.
+	 * @throws IllegalArgumentException if value provided for any parameter is
+	 * not valid according to its description.
+	 */
+	public Owner(String login, String password) {
+		this.setLogin(login);
+		this.changePassword(password);
+		this.pets = new ArrayList<>();
+	}
+	
+	/**
+	 * Creates a new instance of {@code Owner} with pets.
+	 * 
+	 * @param login the login that identifies the user. This parameter must be a
+	 * non empty and non {@code null} string with a maximum length of 100 chars.
+	 * @param password the raw password of the user. This parameter must be a
+	 * non {@code null} string with a minimum length of 4 chars.
+	 * @param pets the pets that belong to this owner. The list of pets can be
+	 * empty. {@code null} values are not supported.
+	 * 
+	 * @throws NullPointerException if a {@code null} value is passed as the
+	 * value for any parameter.
+	 * @throws IllegalArgumentException if value provided for any parameter is
+	 * not valid according to its description.
+	 */
+	public Owner(String login, String password, Pet ... pets) {
+		this.setLogin(login);
+		this.changePassword(password);
+		this.pets = new ArrayList<>();
+		
+		stream(pets).forEach(this::addPet);
+	}
+
+	/**
+	 * Returns the login of this owner.
+	 * 
+	 * @return the login of this owner.
+	 */
+	public String getLogin() {
+		return login;
+	}
+	
+	/**
+	 * Sets the login of this owner.
+	 * 
+	 * @param login the login that identifies the owner. This parameter must be
+	 * a non empty and non {@code null} string with a maximum length of 100 
+	 * chars.
+	 * @throws NullPointerException if {@code null} is passed as parameter.
+	 * @throws IllegalArgumentException if the length of the string passed is
+	 * not valid.
+	 */
+	public void setLogin(String login) {
+		requireNonNull(login, "login can't be null");
+		inclusiveBetween(1, 100, login.length(), "login must have a length between 1 and 100");
+		
+		this.login = login;
+	}
+	
+	/**
+	 * Returns the MD5 of the owner's password. Capital letters are used in the
+	 * returned string.
+	 * 
+	 * @return the MD5 of the owner's password. Capital letters are used in the
+	 * returned string.
+	 */
+	public String getPassword() {
+		return password;
+	}
+	
+	/**
+	 * Sets the MD5 password of the owner. The MD5 string is stored with capital
+	 * letters.
+	 * 
+	 * @param password the MD5 password of the user. This parameter must be a
+	 * non {@code null} MD5 string.
+	 * @throws NullPointerException if {@code null} is passed as parameter.
+	 * @throws IllegalArgumentException if the string passed is not a valid MD5
+	 * string.
+	 */
+	public void setPassword(String password) {
+		requireNonNull(password, "password can't be null");
+		matchesPattern(password, "[a-zA-Z0-9]{32}", "password must be a valid uppercase MD5 string");
+		
+		this.password = password.toUpperCase();
+	}
+	
+	/**
+	 * Changes the password of the owner. This method receives the raw value of
+	 * the password and stores it in MD5 format.
+	 * 
+	 * @param password the raw password of the user. This parameter must be a
+	 * non {@code null} string with a minimum length of 6 chars.
+	 * 
+	 * @throws NullPointerException if the {@code password} is {@code null}.
+	 * @throws IllegalArgumentException if the length of the string passed is
+	 * not valid.
+	 */
+	public void changePassword(String password) {
+		requireNonNull(password, "password can't be null");
+		if (password.length() < 6)
+			throw new IllegalArgumentException("password can't be shorter than 6");
+		
+		try {
+			final MessageDigest digester = MessageDigest.getInstance("MD5");
+			final HexBinaryAdapter adapter = new HexBinaryAdapter();
+
+			this.password = adapter.marshal(digester.digest(password.getBytes()));
+		} catch (NoSuchAlgorithmException e) {
+			throw new RuntimeException("MD5 algorithm not found", e);
+		}
+	}
+	
+	/**
+	 * Returns the pets that belongs to this owner. The collection returned is
+	 * unmodifiable and no order are guaranteed.
+	 * If the pet already belongs to this owner, no action will be done.
+	 * 
+	 * @return the pets that belongs to this owner. 
+	 */
+	public Collection<Pet> getPets() {
+		return unmodifiableCollection(pets);
+	}
+	
+	/**
+	 * Adds a pet to this owner. The pet's owner will be set to this instance.
+	 * 
+	 * @param pet the pet to add to this owner. {@code null} values not
+	 * supported.
+	 * @throws NullPointerException if the {@code pet} is {@code null}.
+	 */
+	public void addPet(Pet pet) {
+		requireNonNull(pet, "pet can't be null");
+		
+		if (!this.ownsPet(pet)) {
+			pet.setOwner(this);
+		}
+	}
+	
+	/**
+	 * Removes a pet from this owner. The pet's owner will be set to
+	 * {@code null}.
+	 * 
+	 * @param pet the pet to remove from this owner. {@code null} values not
+	 * supported.
+	 * @throws NullPointerException if the {@code pet} is {@code null}.
+	 * @throws IllegalArgumentException if the {@code pet} does not belong to
+	 * this owner.
+	 */
+	public void removePet(Pet pet) {
+		requireNonNull(pet, "pet can't be null");
+		
+		if (this.ownsPet(pet)) {
+			pet.setOwner(null);
+		} else {
+			throw new IllegalArgumentException("pet doesn't belong to this owner");
+		}
+	}
+	
+	/**
+	 * Checks if a pet belongs to this owner.
+	 * 
+	 * @param pet the pet whose property will be checked.
+	 * @return {@code true} if the pet belongs to this owner. {@code false}
+	 * otherwise.
+	 */
+	public boolean ownsPet(Pet pet) {
+		return this.pets.contains(pet);
+	}
+	
+	/**
+	 * Adds a pet directly to the pets collection of this owner if the pet does
+	 * not already belongs to this owner. The pet's owner will not be updated.
+	 * 
+	 * @param pet the pet to add to this owner. {@code null} values not
+	 * supported.
+	 * @throws NullPointerException if the {@code pet} is {@code null}.
+	 */
+	void internalAddPet(Pet pet) {
+		requireNonNull(pet, "pet can't be null");
+		
+		if (!this.ownsPet(pet))
+			this.pets.add(pet);
+	}
+	
+	/**
+	 * Removes a pet directly from the pets collection of this owner. The pet's
+	 * owner will not be updated.
+	 * 
+	 * @param pet the pet to remove from this owner. {@code null} values not
+	 * supported.
+	 * @throws NullPointerException if the {@code pet} is {@code null}.
+	 */
+	void internalRemovePet(Pet pet) {
+		requireNonNull(pet, "pet can't be null");
+		
+		this.pets.remove(pet);
+	}
+}

domain/src/main/java/es/uvigo/esei/xcs/domain/entities/Pet.java

+package es.uvigo.esei.xcs.domain.entities;
+
+import static java.util.Objects.requireNonNull;
+import static org.apache.commons.lang3.Validate.inclusiveBetween;
+
+import java.io.Serializable;
+import java.util.Date;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.EnumType;
+import javax.persistence.Enumerated;
+import javax.persistence.GeneratedValue;
+import javax.persistence.Id;
+import javax.persistence.JoinColumn;
+import javax.persistence.ManyToOne;
+import javax.persistence.Temporal;
+import javax.persistence.TemporalType;
+
+/**
+ * A pet.
+ * 
+ * @author Miguel Reboiro-Jato
+ */
+@Entity
+public class Pet implements Serializable {
+	private static final long serialVersionUID = 1L;
+	
+	@Id
+	@GeneratedValue
+	private int id;
+	
+	@Column(length = 100, nullable = false)
+	private String name;
+	
+	@Column(nullable = false, length = 4)
+	@Enumerated(EnumType.STRING)
+	private AnimalType animal;
+	
+	@Column(nullable = false)
+	@Temporal(TemporalType.TIMESTAMP)
+	private Date birth;
+	
+	@ManyToOne
+	@JoinColumn(name = "owner")
+	private Owner owner;
+	
+	// Required for JPA
+	Pet() {}
+	
+	/**
+	 * Creates a new instance of {@code Pet} without owner.
+	 * 
+	 * @param name the name of the pet. This parameter must be a non empty and
+	 * non {@code null} string with a maximum length of 100 chars.
+	 * @param animal the type of animal. This parameter can not be {@code null}.
+	 * @param birth the date of birth of this pet. This parameter can not be
+	 * {@code null} and the date can not be after the current date.
+	 * 
+	 * @throws NullPointerException if a {@code null} value is passed as the
+	 * value for any parameter.
+	 * @throws IllegalArgumentException if value provided for any parameter is
+	 * not valid according to its description.
+	 */
+	public Pet(String name, AnimalType animal, Date birth) {
+		this(name, animal, birth, null);
+	}
+	
+	/**
+	 * Creates a new instance of {@code Pet} with owner.
+	 * 
+	 * @param name the name of the pet. This parameter must be a non empty and
+	 * non {@code null} string with a maximum length of 100 chars.
+	 * @param animal the type of animal. This parameter can not be {@code null}.
+	 * @param birth the date of birth of this pet. This parameter can not be
+	 * {@code null} and the date can not be after the current date.
+	 * @param owner the owner of the pet. {@code null} value is valid,
+	 * meaning that the pet has no owner.
+	 * 
+	 * @throws NullPointerException if a {@code null} value is passed as the
+	 * value for any parameter except for {@code owner}.
+	 * @throws IllegalArgumentException if value provided for any parameter is
+	 * not valid according to its description.
+	 */
+	public Pet(String name, AnimalType animal, Date birth, Owner owner) {
+		this.setName(name);
+		this.setAnimal(animal);
+		this.setBirth(birth);
+		this.setOwner(owner);
+	}
+
+	/**
+	 * Returns the name of the pet.
+	 * 
+	 * @return the name of the pet.
+	 */
+	public String getName() {
+		return name;
+	}
+
+	/**
+	 * Sets the name of the pet.
+	 * 
+	 * @param name the new name of the pet. This parameter must be a non empty
+	 * and non {@code null} string with a maximum length of 100 chars.
+	 * 
+	 * @throws NullPointerException if a {@code null} value is passed.
+	 * @throws IllegalArgumentException if the length of the string passed is
+	 * not valid.
+	 */
+	public void setName(String name) {
+		requireNonNull(name, "name can't be null");
+		inclusiveBetween(1, 100, name.length(), "name must have a length between 1 and 100");
+		
+		this.name = name;
+	}
+
+	/**
+	 * Returns the type of animal of this pet.
+	 * 
+	 * @return the type of animal of this pet.
+	 */
+	public AnimalType getAnimal() {
+		return animal;
+	}
+
+	/**
+	 * Sets the animal type of this pet.
+	 * 
+	 * @param animal the new animal type for this pet. This parameter can not be
+	 * {@code null}.
+	 * 
+	 * @throws NullPointerException if a {@code null} value is passed.
+	 */
+	public void setAnimal(AnimalType animal) {
+		requireNonNull(animal, "animal can't be null");
+		
+		this.animal = animal;
+	}
+
+	/**
+	 * Returns the date of birth of this pet.
+	 * 
+	 * @return the date of birth of this pet.
+	 */
+	public Date getBirth() {
+		return birth;
+	}
+
+	/**
+	 * Sets the date of birth of this pet.
+	 * 
+	 * @param birth the new date of birth for this pet. This parameter can not
+	 * be {@code null} and the date can not be previous to the current date.
+	 * 
+	 * @throws NullPointerException if a {@code null} value is passed.
+	 * @throws IllegalArgumentException if the value provided is after the
+	 * current date.
+	 */
+	public void setBirth(Date birth) {
+		requireNonNull(birth, "birth can't be null");
+		inclusiveBetween(new Date(0), new Date(), birth,
+			"birth must be previous to the current time"
+		);
+		
+		this.birth = birth;
+	}
+
+	/**
+	 * Returns the owner of this pet. The value returned can be {@code null},
+	 * meaning that the pet has no owner.
+	 * 
+	 * @return the owner of this pet.
+	 */
+	public Owner getOwner() {
+		return owner;
+	}
+
+	/**
+	 * Sets the owner of this pet. The new owner can be {@code null}, meaining
+	 * that the pet has no owner.
+	 * 
+	 * @param owner the new owner of the pet. {@code null} value is valid,
+	 * meaning that the pet has no owner.
+	 */
+	public void setOwner(Owner owner) {
+		if (this.owner != null)
+			this.owner.internalRemovePet(this);
+		
+		this.owner = owner;
+		
+		if (this.owner != null)
+			this.owner.internalAddPet(this);
+	}
+}