Using custom properties in your own data models


In the object class you wish to extend with dynamic properties, add the following

1. Imports 

  import com.k_int.svc.custprops.datamodel.*

2. Implement..

In order to use the static helper methods, your class must implement the
following interface:

public interface DynamicPropertyObject {
  public Map<PropertyDefinitionHDO,PropertyValueHDO> getProperties();
}

found in the datamodel package.

3. A map to contain the dynamic properties

  protected Map<PropertyDefinitionHDO,PropertyValueHDO> properties = new HashMap<PropertyDefinitionHDO,PropertyValueHDO>();
  protected Set<TagHDO> tags = new Set<TagHDO>();

4. getters and setters

4.1. For dynamic properties

  @ManyToMany(cascade = CascadeType.ALL)
  @Cascade({org.hibernate.annotations.CascadeType.SAVE_UPDATE, org.hibernate.annotations.CascadeType.DELETE_ORPHAN})
  @JoinColumn(name="MY_CLASS_FK")
  @JoinTable(name="MY_CLASS_PROP_VALUE")
  public Map<PropertyDefinitionHDO,PropertyValueHDO> getProperties() {
    return properties;
  }

  public void setProperties(Map<PropertyDefinitionHDO,PropertyValueHDO> properties) {
    this.properties = properties;
  }

4.2. For being able to tag objects

  @ManyToMany(cascade = CascadeType.ALL)
  @Cascade({org.hibernate.annotations.CascadeType.SAVE_UPDATE,
  org.hibernate.annotations.CascadeType.DELETE_ORPHAN})
  @JoinColumn(name="MY_CLASS_FK")
  @JoinTable(name="MY_CLASS_TAG")
  public Set<TagHDO> getTags() {
    return tags;
  }

  public void setTags(Set<TagHDO> tags) {
    this.tags = tags;
  }

** use a JoinTable name MY_CLASS_PROP_VALUE specific to your source class. This table will contain only custom properties for the
** specified class.

5. Hibernate annotated classes: Add the following to the spring definitions

        <value>com.k_int.svc.custprops.datamodel.PropertyDefinitionHDO</value>
        <value>com.k_int.svc.custprops.datamodel.PropertyValueHDO</value>
        <value>com.k_int.svc.custprops.datamodel.LocalisedStringValueHDO</value>
        <value>com.k_int.svc.custprops.datamodel.SimpleStringValueHDO</value>
        <value>com.k_int.svc.custprops.datamodel.IdentifierValueHDO</value>
        <value>com.k_int.svc.custprops.datamodel.TagHDO</value>


6. Programatically Adding and removing properties...

Supposing we have a class called Resource containing only an identifieri (And
implementing the DynamicPropertyObject interface, and
using the steps above we have added a properties map to that resource. In
order to set the dynamic simple property dublin core title to "Test Widget" we would
need to do something like

public static String DC_TITLE_PROP_URI = "";

Resource my_res = xxx;
DynamicPropertyHelper.setSimpleProperty(session,my_res,DC_TITLE_PROP_URI,"Test Widget");

to Set a dynamic localised property (What a DC Title really should be);

DynamicPropertyHelper.setLocalisedStringProperty(session,my_res,DC_TITLE_PROP_URI,java.util.Locale.UK,"Test Widget");
DynamicPropertyHelper.setLocalisedStringProperty(session,my_res,DC_TITLE_PROP_URI,java.util.Locale.FRANCE,"Le Widget du Test");


7. Hibernate searching against dynamic properties

8. Future directions

8.1 Alternatives.. Currently, a resource may only have one value of a
property, for example one DC.title, althoug it may have many language
variants. We will need to add "Alternates" at some point for lists of values
etc.


9. Using schemas to manage collections of dynamic factories

@ManyToMany(cascade = CascadeType.ALL)
@Cascade({org.hibernate.annotations.CascadeType.SAVE_UPDATE, org.hibernate.annotations.CascadeType.DELETE_ORPHAN})
@JoinColumn(name="MY_CLASS_FK")
@JoinTable(name="MY_CLASS_SCHEMA")
public Set<SchemaDefinitionHDO> getSchemas() {
  return schemas;
}

public void setSchemas(Set<SchemaDefinitionHDO> schemas) {
    this.schemas = schemas;
}