As the SQL repository parses the XML repository definition file, it creates an instance of your RepositoryPropertyDescriptor class and stores it directly in the SQL repository’s list of property descriptors for each item descriptor. The SQL repository calls the setItemDescriptor method to associate your property with the item descriptor to which it belongs. You typically do not need to be aware of that. Then, the SQL repository calls one or more methods corresponding to the property’s type:
RepositoryPropertyDescriptor.setPropertyType()
GSAPropertyDescriptor.setComponentPropertyType()
RepositoryPropertyDescriptor.setPropertyItemDescriptor()
If this property refers to another item’s type, this method sets the item descriptor for that type.
RepositoryPropertyDescriptor.setComponentItemDescriptor()
depending on which attributes are set in the <property> tag (data-type, item-type, component-data-type, or component-item-type). They define the property’s Java class, the component’s property class (if the property is a multi-valued property), the RepositoryItemDescriptor for either a scalar or a multi-valued property which refers to other item types.
If your property type can accept any of these values, you do not need to override these methods. If your property is constrained in what data types it supports (which is generally the case), you should put error checking logic into these methods to throw errors if an invalid type is specified. Your property descriptor should throw the unchecked IllegalArgumentException to provide details about what type is required. If your property type is very restrictive, you can implement these methods to return the appropriate values:
This will prevent developers of repository definitions from having to set the data-type, component-data-type, item-type, and component-item-type attributes. You may still want to put error checking in these methods to signal errors if they do provide invalid values.
When you attempt to get or set one of these property values, your getPropertyValue or setPropertyValue method is called. The SQL repository provides the RepositoryItemImpl class as an argument to these methods so that you can call the methods setPropertyValue and getPropertyValue of the underlying item. If you call these methods with the same name as your property (this is available in the getName() method on your RepositoryPropertyDescriptor class), it will result in an infinite loop, so be careful.
The getPropertyValue method receives an extra Object pValue argument. This is set to any value we’ve found in the cache for this property name, if any, or null if no value is in the cache. In your setPropertyValue method, you can call setPropertyValueInCache(this, yourvalue) if you’d like to cache this property value for subsequent method calls.
If your property is not set, you may choose to return the value of the getDefault() method on the RepositoryPropertyDescriptor. This will allow the user to set the default value for this property using the default attribute in the XML tag. This method calls setDefaultValueString, which converts the default value based on the class returned by getPropertyType, which then calls setDefaultValue. You may choose to modify this behavior by overriding these methods though typically this functionality is sufficient.
Note that user defined properties must be serializable. The getPropertyValue and setPropertyValue methods do not need to work on an unserialized version, but the getPropertyType, getComponentType, getPropertyItemDescriptor, and getComponentItemDescriptor methods in particular do need to work. This is important so that the ATG Control Center can understand the type of property it is editing.
To make your user-defined property queryable, it should represent a database column. Unless your user-defined property extends GSAPropertyDescriptor, then the property is not queryable and you should implement the method isQueryable to return false. If you want your user-defined property to be queryable, make sure it extends GSAPropertyDescriptor. You may also override the methods isWritable and isReadable to turn off write access or read access to your property respectively. Other methods such as isHidden, isExpert can also be overridden if you want to set additional Bean attributes. The method setValue(String pName, Object pValue) is called if any feature descriptor attributes are supplied with this property.
