JarCastingOO-Data
Tool for generating data-like interfaces with basic structural subtyping support.
Quick start
- Add Maven dependency:
<dependency>
<groupId>com.pragmaticobjects.oo.data</groupId>
<artifactId>data-alltogether</artifactId>
<version>0.0.0-SNAPSHOT</version>
</dependency>
- Describe your data by annotating
package-info.java:
@Scalar(value = "UserName", type = String.class)
@Scalar(value = "UserAvatar", type = URI.class)
@Scalar(value = "UserLocation", type = String.class)
@Structure(value = "UserVisualInfo", has = {"UserName", "UserAvatar"})
@Structure(value = "UserContactInfo", has = {"UserName", "UserLocation"})
@Structure(value = "UserFullInfo", has = {"UserName", "UserAvatar", "UserLocation"})
package your.package.name;
- Build the project. OO-Data processes annotations on build phase and generates:
- interfaces for your data:
UserName,UserAvatar,UserLocation,UserVisualInfo,UserContactInfo,UserFullInfo - value objects:
UserNameValue,UserAvatarValue, etc. - composite objects:
UserVisualInfoComposite,UserContactInfoComposite, etc.
- Have fun
What sort of fun?
- Structures are always subtypes from scalars they have inside:
UserVisualInfo userInfo = ...;
UserName name = userInfo; // correct
UserAvatar avatar = userInfo; // correct
UserLocation loc = userInfo; // incorrect! Location is not visual information.
- You can substitute larger structures in places where smaller ones are required:
UserFullInfo userFullInfo = ...;
UserContactInfo info = userFullInfo; // full information includes contact information, it's okay
- You can compose structures from scalars and other structures:
// from separate scalars...
UserFullInfo info = new UserFullInfoComposite(
new UserNameValue("Sergey Kapralov"),
new UserAvatarValue(url),
new UserLocation("Nizhniy Novgorod, Russia")
);
// Or even from other structures
UserVisualInfo visualInfo = new UserVisualInfoValue("Sergey Kapralov", avatarUrl);
UserContactInfo contactInfo = new UserContactInfo("Sergey Kapralov", "Nizhniy Novgorod, Russia");
UserFullInfo fullInfo = new UserFullInfoComposite(
new UserNameValue("Kapralov Sergey"),
visualInfo, // avatar will be taken from visualInfo
contactInfo // location - from contactInfo
);
- More tricks to come later...
