package ejava.examples.orm.inheritance.annotated;
   
   import javax.persistence.*;
   
   /**
    * This class provides an example base class in a single table inheritance
    * strategy. In this case, a single table is defined to hold the properties of
    * all sub-classes. A discriminator field is necessary to denote the type
    * of each row in the table. Note that the primary key is being generated 
   * here since this class definition is shared among the sub-classes.
   */
  @Entity @Table(name="ORMINH_PRODUCT")
  @Inheritance(strategy=InheritanceType.SINGLE_TABLE)
  @DiscriminatorColumn(name="PTYPE", //column in root table indicating type
      discriminatorType=DiscriminatorType.STRING,//data type of column
      length=32) //length of discriminator string
  public abstract class Product {
      @Id @GeneratedValue
      private long id;
      private double cost;
      
      protected Product() {}
      protected Product(long id) { this.id=id; }
      public long getId() { return id; }
  
      public double getCost() {
          return cost;
      }
      public void setCost(double cost) {
          this.cost = cost;
      }
      
      @Transient
      public abstract String getName();
      
      public String toString() {
          StringBuilder text = new StringBuilder(super.toString());
          text.append(", id=" + id);
          text.append(", cost=" + cost);
          return text.toString();
      }
  }