= Visit module and entity

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Our domain model now consists of the `PetOwner` and `Pet` entities (along with the `PetSpecies`  enum).
In this section we'll add in the `Visit` entity:

include::partial$domain.adoc[]

Also, note that the `Visit` entity is in its own module.
We'll look at the important topic of modularity in later exercises.


[#exercise-5-1-the-visits-module]
== Ex 5.1: The visits module

In this exercise we'll just create an empty visits module.

=== Solution

[source,bash]
----
git checkout tags/05-01-visit-module
mvn clean install
mvn -pl spring-boot:run
----


=== Tasks

Just check out the tag above and inspect the changes:

* A new `petclinic-module-visits` maven module has been created

* its `pom.xml` declares a dependency on the `petclinic-module-pets` maven module

* the top-level pom.xml declares the new Maven module and references it

* the `VisitsModule` class is a Spring `@Configuration` bean that resides in the root of the visits module, and declares an app dependency on the pets module that mirrors the maven dependency:
+
[source,java]
.VisitsModule.java
----
@Configuration
@ComponentScan
@Import(PetsModule.class)
@EnableJpaRepositories
@EntityScan(basePackageClasses = {VisitsModule.class})
public class VisitsModule implements ModuleWithFixtures {

    @Override
    public FixtureScript getTeardownFixture() {
        return new FixtureScript() {
            @Override
            protected void execute(ExecutionContext executionContext) {
                // nothing to do
            }
        };
    }
}
----

* the webapp Maven module now depends on the new visits maven module, and the top-level `ApplicationModule` Spring `@Configuration` bean now depends upon `VisitsModule` rather than `PetsModule`
+
It still depends upon `PetsModule`, but now as a transitive dependency.


[#exercise-5-2-visit-entitys-key-properties]
== Ex 5.2: Visit entity's key properties

Now we have a visits module, we can now add in the `Visit` entity.
We'll start just with the key properties.


[source,bash]
----
git checkout tags/05-02-visit-entity-key-properties
mvn clean install
mvn -pl spring-boot:run
----


=== Tasks

* add a `Visit` entity, declaring the `pet` and `visitedAt` key properties:
+
[source,java]
.Visit.java
----
@Entity
@Table(
    schema="visits",        // <.>
    name = "Visit",
    uniqueConstraints = {
        @UniqueConstraint(name = "Visit__pet_visitAt__UNQ", columnNames = {"owner_id", "name"})
    }
)
@EntityListeners(IsisEntityListener.class)
@DomainObject(logicalTypeName = "visits.Visit", entityChangePublishing = Publishing.ENABLED)
@DomainObjectLayout()
@NoArgsConstructor(access = AccessLevel.PUBLIC)
@XmlJavaTypeAdapter(PersistentEntityAdapter.class)
@ToString(onlyExplicitlyIncluded = true)
public class Visit implements Comparable<Visit> {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id", nullable = false)
    @Getter @Setter
    @PropertyLayout(fieldSetId = "metadata", sequence = "1")
    private Long id;

    @Version
    @Column(name = "version", nullable = false)
    @PropertyLayout(fieldSetId = "metadata", sequence = "999")
    @Getter @Setter
    private long version;


    Visit(Pet pet, LocalDateTime visitAt) {
        this.pet = pet;
        this.visitAt = visitAt;
    }


    public String title() {
        return titleService.titleOf(getPet()) + " @ " + getVisitAt().format(DateTimeFormatter.ofPattern("dd-MM-yyyy HH:mm"));
    }

    @ManyToOne(optional = false)
    @JoinColumn(name = "pet_id")
    @PropertyLayout(fieldSetId = "name", sequence = "1")
    @Getter @Setter
    private Pet pet;

    @Column(name = "visitAt", nullable = false)
    @Getter @Setter
    @PropertyLayout(fieldSetId = "name", sequence = "2")
    private LocalDateTime visitAt;


    private final static Comparator<Visit> comparator =
            Comparator.comparing(Visit::getPet).thenComparing(Visit::getVisitAt);

    @Override
    public int compareTo(final Visit other) {
        return comparator.compare(this, other);
    }

    @Inject @Transient TitleService titleService;
}
----
<.> in the "visits" schema.
Modules are vertical, cutting through the layers.
Therefore the database schemas echo the Spring ``@Configuration``s and maven modules.
+
Run the application, and confirm that the table is created correctly using menu:Prototyping[H2 Console].


[#exercise-5-3-book-visit-action]
== Ex 5.3: "Book Visit" action

In addition to the key properties, the `Visit` has one further mandatory property, `reason`.
This is required to be specified when a `Visit` is created ("what is the purpose of this visit?")

In this exercise we'll add that additional property and use a mixin to allow ``Visit``s to be created.


[source,bash]
----
git checkout tags/05-03-schedule-visit-action
mvn clean install
mvn -pl spring-boot:run
----


=== Tasks

* add the `@Reason` meta-annotation
+
[source,java]
.Reason.java
----
@Property(maxLength = Reason.MAX_LEN)
@PropertyLayout(named = "Reason")
@Parameter(maxLength = Reason.MAX_LEN)
@ParameterLayout(named = "Reason")
@Target({ ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER, ElementType.ANNOTATION_TYPE })
@Retention(RetentionPolicy.RUNTIME)
public @interface Reason {

    int MAX_LEN = 255;
}
----

* add the `reason` mandatory property:
+
[source,java]
.Visit.java
----
@Reason
@Column(name = "reason", length = FirstName.MAX_LEN, nullable = false)
@Getter @Setter
@PropertyLayout(fieldSetId = "details", sequence = "1")
private String reason;
----


* update constructor (as this is a mandatory property)
+
[source,java]
.Visit.java
----
Visit(Pet pet, LocalDateTime visitAt, String reason) {
    this.pet = pet;
    this.visitAt = visitAt;
    this.reason = reason;
}
----

* create a "visits" mixin collection as a mixin of `Pet`, so we can see the ``Visit``s that have been booked:
+
[source,java]
.Pet_visits.java
----
@Collection
@CollectionLayout(defaultView = "table")
@RequiredArgsConstructor
public class Pet_visits {

    private final Pet pet;

    public List<Visit> coll() {
        return visitRepository.findByPetOrderByVisitAtDesc(pet);
    }

    @Inject VisitRepository visitRepository;
}
----

* create a "bookVisit" mixin action (in the visits module), as a mixin of `Pet`.
+
We can use xref:refguide:applib:index/services/clock/ClockService.adoc[ClockService] to ensure that the date/time specified is in the future, and to set a default date/time for "tomorrow"
+
[source,java]
.Pet_bookVisit.java
----
@Action(
        semantics = SemanticsOf.IDEMPOTENT,
        commandPublishing = Publishing.ENABLED,
        executionPublishing = Publishing.ENABLED
)
@ActionLayout(associateWith = "visits", sequence = "1")
@RequiredArgsConstructor
public class Pet_bookVisit {

    private final Pet pet;

    public Visit act(
            LocalDateTime visitAt,
            @Reason final String reason
            ) {
        return repositoryService.persist(new Visit(pet, visitAt, reason));
    }
    public String validate0Act(LocalDateTime visitAt) {
        return clockService.getClock().nowAsLocalDateTime().isBefore(visitAt)   // <.>
                ? null
                : "Must be in the future";
    }
    public LocalDateTime default0Act() {
        return clockService.getClock().nowAsLocalDateTime()                     // <.>
                .toLocalDate()
                .plusDays(1)
                .atTime(LocalTime.of(9, 0));
    }

    @Inject ClockService clockService;
    @Inject RepositoryService repositoryService;
}
----
<.> ensures that the date/time specified is in the future.
<.> defaults to 9am tomorrow morning.

Also add in the UI files:

* create a `Visit.layout.xml` layout file.

* add a `Visit.png` file

* add a `Pet#visits.columnOrder.txt` file
+
to define which properties of Visit are visible as columns in ``Pet``'s `visits` collection.


=== Optional exercises

NOTE: If you decide to do this optional exercise, make the changes on a git branch so that you can resume with the main flow of exercises later.

. Download a separate `Visit-NN.png` for each of the days of the month (1 to 31), and then use `iconName()` to show a more useful icon based on the `visitAt` date.

. Use choices to provide a set of available date/times, in 15 minutes slots, say.

. Refine the list of slots to filter out any visits that already exist
+
Assume that visits take 15 minutes, and that only on visit can happen at a time.