Examples -> this

Abstract Class Example

This example show how the annotations work on an abstract class. Note that the entity manger creates an instance of the abstract class. This class is the similar to the interface example except that it uses the List<String> return type for getAuthor() and with the addition of a cite() method that produces a cite entry for the book.

Book Class

@Subject( namespace="http://example.com/PA4RDF#" )
public abstract class Book {

    @Predicate
    abstract void setTitle( String title );
    abstract String getTitle();

    @Predicate
    abstract void addAuthor( String author );
    abstract List<String> getAuthor();

    @Predicate
    abstract void setPageCount( Integer int );
    abstract boolean hasPageCount();
    abstract int getPageCount();

    public String cite() {
      StringBuilder sb = new StringBuilder();
      for (String author : getAuthor() )
      {
        sb.append( author ).append( ", " );
      }
      sb.append( getTitle() ).append( "." );
      if (book.hasPageCount())
      {
        sb.append(" pgs: ").append( getPageCount() );
      }
      return sb.toString();
    }
}

Example code setting the Book class

Model model = ModelFactory.createModel();

EntityManager entityManager = EntityManagerFactory.getEntityManager(model);
Resource r = model.createResource( "http://example.com/mylibrary/book1" );

Book book = EntityManager.read( r, Book.class );
book.setTitle( "Java Generics and Collections" );
book.addAuthor( "Maurice Naftalin" );
book.addAuthor( "Philip Wadler" );
book.setPageCount( 286 );

Result of example code

The above code will result in the following graph:

<http://example.com/mylibrary/book1> 
    <http://example.com/PA4RDF#title> "Java Generics and Collections" ;
    <http://example.com/PA4RDF#author> "Maurice Naftalin" ;
    <http://example.com/PA4RDF#author> "Philip Wadler" ;
    <http://example.com/PA4RDF#pageCount> "286"^^<xsd:integer> ;
.

Example code reading the Book class

Assuming the book object has been constructed as in the first example.

System.out.println( "Title: "+book.getTitle() );
for (String author : book.getAuthor() )
{
    System.out.println( "  Author: "+author );
}
if (book.hasPageCount())
{
    System.out.println( "  Pages: "+book.getPageCount() );
}
System.out.println( book.cite() );

This will result in the following output:

Title: Java Generics and Collections
  Author: Maurice Naftalin
  Author: Philip Wadler
  Pages: 286
Maurice Naftalin, Philip Wadler, Java Generics and Collections. pgs: 286