= Title Cache

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The _Titlecache_ extension module provides a simple way to cache titles of entities for a configurable duration.
This can speed up the rendering time of data-heavy objects.

The current implementation uses the link:https://github.com/ben-manes/caffeine[Caffeine] caching library.

== Dependency Management

[source,xml,subs="attributes+"]
.pom.xml
----
<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.apache.causeway.extensions</groupId>
            <artifactId>causeway-extensions-titlecache</artifactId>
            <scope>import</scope>
            <type>pom</type>
            <version>{page-causewayprevv3}</version>
        </dependency>
    </dependencies>
</dependencyManagement>
----

[#dependencies]
=== Dependencies

For the module of every entity whose title you want to cache, add the following dependency:

[source,xml,subs="attributes+"]
.pom.xml
----
<dependencies>
    <dependency>
        <groupId>org.apache.causeway.extensions</groupId>
        <artifactId>causeway-extensions-titlecache-applib</artifactId>
    </dependency>
</dependencies>
----

And, in the webapp module of your application, add the following dependency:

[source,xml,subs="attributes+"]
.pom.xml
----
<dependencies>
    <dependency>
        <groupId>org.apache.causeway.extensions</groupId>
        <artifactId>causeway-extensions-titlecache-caffeine</artifactId>
    </dependency>
</dependencies>
----

[#appmanifest]
=== AppManifest

In your application's `AppManifest` (top-level Spring `@Configuration` used to bootstrap the app), import the `CausewayModuleExtTitlecacheCaffeine` module.

[source,java]
.AppManifest.java
----
@Configuration
@Import({
        ...
        CausewayModuleExtTitlecacheCaffeine.class,
        ...
})
public class AppManifest {
}
----


== Usage

For each entity class whose title is to be cached, create a subclass of xref:refguide:applib:index/events/ui/TitleUiEvent.adoc[] that also implements the xref:refguide:extensions:index/titlecache/applib/event/Cached.adoc[Cached] marker interface, and mark it as the event class fpr xref:refguide:applib:index/annotation/DomainObjectLayout.adoc#titleUiEvent[@DomainObjectLayout#titleUiEvent]:

[source,java]
----
@DomainObject
@DomainObjectLayout(
    titleUiEvent = Customer.TitleUiEvent.class
)
public class Customer /*...*/ {

    public static class TitleUiEvent extends CausewayModuleApplib.TitleUiEvent<Customer> implements Cached { }

    // ...
}
----

The titles of these entities will be cached according to the default xref:#configuration[configuration].

Or, for more control on an given entity, implement the xref:refguide:extensions:index/titlecache/applib/event/CachedWithCacheSettings.adoc[] interface:

[source,java]
----
@DomainObject
@DomainObjectLayout(
    titleUiEvent = Customer.TitleUiEvent.class
)
public class Customer /*...*/ {

    public static class TitleUiEvent extends CausewayModuleApplib.TitleUiEvent<Customer> implements CachedWithCacheSettings {
        @Override public int expiryDurationInMinutes() { return 1;}
        @Override public int maxSizeInEntries() {return 50;}
    }

    // ...
}
----



[#configuration]
== Configuration

Two configuration properties can be set:

* xref:refguide:config:sections/causeway.extensions.adoc#causeway.extensions.titlecache.caffeine.expiry-duration-in-minutes[causeway.extensions.titlecache.caffeine.expiry-duration-in-minutes]
* xref:refguide:config:sections/causeway.extensions.adoc#causeway.extensions.titlecache.caffeine.max-size-in-entries[causeway.extensions.titlecache.caffeine.max-size-in-entries]

