Script units accessing Virtual Entities

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Contents 1 Retrieving data from Virtual Entities 2 Deleting data from Virtual Entities 3 Adding data to Virtual Entities 4 VirtualEntityTable class 5 Download the example

Retrieving data from Virtual Entities

The Script Unit has multiple usages: transform input in output, access database and access virtual entities. Consider the article Script units accessing database and reproduce the same situation but using two virtual entities: VCategory and VProduct and the 1:N relationship VProduct_VCategory

As in the database example, suppose we want to know how many products belong to the category of the selected product, in addition to the selected one. We use an XMLOut unit in order to export the data stored in the database and an Adapter unit in order to create the right XML that is used to populate the virtual tables through the XMLIn unit. Your site view can appear as in the image below.

The script code to retrieve the number of products is:

#input int categoryOID

import com.webratio.rtx.core.BeanHelper
import org.apache.commons.lang.math.NumberUtils
import com.webratio.rtx.vdb.VirtualEntityTable
import com.webratio.webapp.VCategory

def count = 0
def entityId = "ent10"

/* obtains the model service */
def ms = rtx.getModelService()

/* creates an instance of VirtualEntityTable using the VCategory entity id */
def table = new VirtualEntityTable(entityId, sessionContext, service)

/* extracts the entity key attributes ids */
def attrId = ms.getKeyAttributeIds(entityId)[0]

/* obtains the field name of the key attribute */
def fieldName = ms.getAttributeFieldName(attrId)
   
/* creates the keys map */
def keyMap = [:]
keyMap[fieldName] = categoryOID

/* obtains the category object finding it by key */
VCategory category = (VCategory) table.findByKey(keyMap)

/* navigates the Category to Product role to obtain the category's products */	
def products = category.getVCategory2VProduct()
count = products.size()
if (count != 0) {
 	count--
}
return count

Note that the method getVCategory2VProduct() is a method of the generated class VCategory that you can find in <pathToApplication>/WEB-INF/classes/com/webratio/webapp folder where all classes and hibernate config files are stored. If the name of the entity or of the roles are changed the script must be updated using the same names.

Deleting data from Virtual Entities

As an example, suppose now that we want to add the functionality to delete a product using a Script Unit (even though we can easily use the Delete Unit). Refer to the following model:

The "delete product" functionality can be accomplished by the following script:

#input int productOID

import com.webratio.rtx.core.BeanHelper
import org.apache.commons.lang.math.NumberUtils
import com.webratio.rtx.vdb.VirtualEntityTable
import com.webratio.webapp.VProduct

def count = 0
def entityId = "ent9"

/* obtains the model service */
def ms = rtx.getModelService()

/* creates an instance of VirtualEntityTable using the VProducts entity id */
def table = new VirtualEntityTable(entityId, sessionContext, service)

/* extracts the entity key attributes ids */
def attrId = ms.getKeyAttributeIds(entityId)[0]

/* obtains the field name of the key attribute */
def fieldName = ms.getAttributeFieldName(attrId)
   
/* creates the keys map */
def keyMap = [:]
keyMap[fieldName] = productOID

/* obtains the product object finding it by key */
VProduct product = (VProduct) table.findByKey(keyMap)

/* disconnects the product from all the entity outgoing role */
table.disconnectBeforeDelete(product)

/* creates a list of Objects for the delete method */
def objectsToDelete = []
objectsToDelete.add(product)

/* deletes from the VProducts table the product received in input */
table.delete(objectsToDelete)

In the following model we are adding the possibility for the user to delete a category and all the products related to it using a Script Unit:

The script that realizes this functionality is as follow:

#input int categoryOID

import com.webratio.rtx.core.BeanHelper
import org.apache.commons.lang.math.NumberUtils
import com.webratio.rtx.vdb.VirtualEntityTable
import com.webratio.webapp.VCategory

def count = 0
def categoryEntityId = "ent10"
def productEntityId = "ent9"

/* obtains the model service */
def ms = rtx.getModelService()

/* creates an instance of VirtualEntityTable using the VCategory entity id */
def categoryTable = new VirtualEntityTable(categoryEntityId, sessionContext, service)
def productTable = new VirtualEntityTable(productEntityId, sessionContext, service)

/* extracts the entity key attributes ids */
def attrId = ms.getKeyAttributeIds(categoryEntityId)[0]

/* obtains the field name of the key attribute */
def fieldName = ms.getAttributeFieldName(attrId)
   
/* creates the keys map */
def keyMap = [:]
keyMap[fieldName] = categoryOID

/* obtains the category object finding it by key */
VCategory category = (VCategory) categoryTable.findByKey(keyMap)

/* navigates the Category to Product role to obtain the category's products */	
def products = category.getVCategory2VProduct()

/* disconnects the category from all the entity outgoing role */
categoryTable.disconnectBeforeDelete(category)

/* creates a list of Objects for the delete method */
def objectsToDelete = []
objectsToDelete.add(category)

/* delete the category */
categoryTable.delete(objectsToDelete)

/* delete all the category's products */
productTable.delete(products)

Adding data to Virtual Entities

Now we want to give to the user the possibility to add a new product. Refer to the following model:

The script that implements this functionality is the following:

#input String categoryName

import com.webratio.rtx.core.BeanHelper
import org.apache.commons.lang.math.NumberUtils
import com.webratio.rtx.vdb.VirtualEntityTable
import com.webratio.webapp.VCategory

def count = 0
def entityId = "ent10"

/* obtains the model service */
def ms = rtx.getModelService()

/* creates an instance of VirtualEntityTable using the VCategory entity id */
def table = new VirtualEntityTable(entityId, sessionContext, service)

/* creating the new VCategory */
VCategory category = new VCategory()
category.setCategory(categoryName)

/* saving the new category */
table.save(category)

Note that it's not necessary to define the value of the oid since it's auto-generated.

VirtualEntityTable class

The VirtualEntityTable class provides some methods that can be used in scripts to retrieve the necessary information from virtual entities. The table below indexes these methods.

Constructor
VirtualEntityTable(String entity, Map sessionCtx, RTXService service) Constructs a new wrapper.	Parameters: entity - the identifier of an entity. sessionCtx - the session context. service - the runtime service. Throws: RTXException

Method Summary
void	connect(Object object, Object targetObject, String roleId) Connects the given object to the target object depending on the role id.	Parameters: object - the object to connect targetObject - the object to which connect the given object roleId - the role to be used for the connection Throws: RTXException
boolean	contains(Object object) Returns true if the given object is already present into this virtual table.	Parameters: object - the volatile object Returns: true if the given object is already present into this virtual table
void	delete(Collection objects) Deletes all the given objects.	Parameters: objects - the collection of objects to be deleted
void	disconnect(Object object, Object targetObject, String roleId) Disconnects the given object from the target object depending on the role id.	Parameters: object - the object to disconnect targetObject - the object from which disconnect the given object roleId - the role to be used for the disconnection Throws: RTXException
void	disconnectBeforeDelete(Object object) Disconnects the given object from all the entity outgoing roles.	Parameters: objects - the volatile object instance Throws: RTXException
List	findByFields(Map fieldMap) Returns all objects depending on the given field values.	Parameters: fieldMap - the map containing all field values by field name Returns: the list of objects depending on the given field values. Throws: RTXException
Object	findByKey(Map key) Finds and returns the object instance by the given key attributes values.	Parameters: key - the map containing the key attribute values by field name Returns: the object instance. Throws: RTXException
Set	getConnectedObjects(Object object, String roleId) Retrieves all the connected objects depending on the role id.	Parameters: object - the volatile object instance roleId - the role to be used to retrieve connected objects Returns: the set of connected objects depending on the role id. Throws: RTXException
String	getEntityId() Gets the entity identifier.	Returns: the entity id.
Map	getKeyMap(Object object) Computes and returns the key attributes map of the given volatile object.	Parameters: object - the volatile object instance Returns: the key attributes map of the given volatile object Throws: RTXException
Object	getRow(index) Returns the object instance at the specified index.	Parameters: index - the index of the row. Returns: the object instance at the specified index.
List	getRows() Retrieves the list of beans, creating a new list (and storing it in the session context) if not found.	Returns: the list of entity beans.
void	save(Object object) Saves a new object in the virtual database. If the associated entity is not a top level entity, the instance is also saved in the list of ancestor entity instances.	Parameters: object - the new object to save. Throws: RTXException
int	size() Gets the size of the virtual table.	Returns: the number of rows.

Download the example

Click on the following link to download a sample project containing all the resources to test this article.

Acme - Accessing Virtual Entities Project

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