net.java.html.json

Annotation Type Model

@Retention(value=SOURCE)
 @Target(value=TYPE)
public @interface Model

Defines a model class that represents a single JSON-like object named className(). The generated class contains getters and setters for properties defined via properties() and getters for other, derived properties defined by annotating methods of this class by ComputedProperty. Each property can be of primitive type, an enum type or (in order to create nested JSON structure) of another class generated by @Model annotation. Each property can either represent a single value or be an array of its values.

The generated class's toString method converts the state of the object into JSON format. One can use Models.parse(net.java.html.BrwsrCtx, java.lang.Class, java.io.InputStream) method to read the JSON text stored in a file or other stream back into the Java model. One can also use @OnReceive annotation to read the model asynchronously from a URL.

An example where one defines class Person with four properties (firstName, lastName, array of addresses and fullName) follows:

 @Model(className="Person", properties={
   @Property(name = "firstName", type=String.class),
   @Property(name = "lastName", type=String.class)
   @Property(name = "addresses", type=Address.class, array = true)
 })
 static class PersonModel {
   @ComputedProperty
   static String fullName(String firstName, String lastName) {
     return firstName + " " + lastName;
   }
 
   @ComputedProperty
   static String mainAddress(List<Address> addresses) {
     for (Address a : addresses) {
       return a.getStreet() + " " + a.getTown();
     }
     return "No address";
   }
 
   @Model(className="Address", properties={
     @Property(name = "street", type=String.class),
     @Property(name = "town", type=String.class)
   })
   static class AddressModel {
   }
 }
 

The generated model class has a default constructor, and also quick instantiation constructor that accepts all non-array properties (in the order used in the properties() attribute) and vararg list for the first array property (if any). One can thus use following code to create an instance of the Person and Address classes:

 Person p = new Person("Jaroslav", "Tulach",
   new Address("Markoušovice", "Úpice"),
   new Address("V Parku", "Praha")
 );
 // p.toString() then returns equivalent of following JSON object
 {
   "firstName" : "Jaroslav",
   "lastName" : "Tulach",
   "addresses" : [
     { "street" : "Markoušovice", "town" : "Úpice" },
     { "street" : "V Parku", "town" : "Praha" },
   ]
 }
 

In case you are using Knockout technology for Java then you can associate such model object with surrounding HTML page by calling: p.applyBindings();. The page can then use regular Knockout bindings to reference your model and create dynamic connection between your model in Java and live DOM structure in the browser:

 Name: <span data-bind="text: fullName">
 <div data-bind="foreach: addresses">
   Lives in <span data-bind="text: town"/>
 </div>
 

Visit an on-line demo to see a histogram driven by the Model annotation or try a little math test.

Author:

Jaroslav Tulach

Required Element Summary

Required Elements

Modifier and Type	Required Element and Description
String	className Name of the model class.
Property[]	properties List of properties in the model.

Element Detail

className

public abstract String className

Name of the model class.

Returns:

valid Java identifier to use as a name of the model class

properties

public abstract Property[] properties

List of properties in the model.

Returns:

array of property definitions