Package org.kuali.rice.krad.data.util

Class ReferenceLinker

java.lang.Object
org.kuali.rice.krad.data.util.ReferenceLinker
public class ReferenceLinker extends Object
The ReferenceLinker provides functionality that allows for ensuring that relationships and foreign key state are populated and kept in sync as changes are made to a data object.

This may include fetching relationships as keys are changed that would necessitate updating the object graph, and may also ensure that foreign key values are kept in sync in situations where a data object may have more than one field or object that stores the same foreign key.

This class has a single method linkChanges(Object, java.util.Set) which takes a data object and a list of property paths for fields which have been modified. It then uses this information determine how to link up relationships and foreign key fields, recursing through the object graph as needed.

Linking occurs from the bottom up, such that this class will attempt to perform a post-order traversal to visit the modified objects furthest from the root first, and then backtracking and linking back to the root. The linking algorithm handles circular references as well to ensure that the linking process terminates successfully.

The ReferenceLinker requires access to the DataObjectService so it must be injected using the provided setDataObjectService(org.kuali.rice.krad.data.DataObjectService) method.

Author:
Kuali Rice Team (rice.collab@kuali.org)

  • Constructor Details

    • ReferenceLinker

      public ReferenceLinker()

  • Method Details

    • getDataObjectService

      public DataObjectService getDataObjectService()
      Returns the DataObjectService used by this class
      Returns:
      the DataObjectService used by this class

    • setDataObjectService

      public void setDataObjectService(DataObjectService dataObjectService)
      Specify the DataObjectService to be used during linking.

      The linker will use the DataObjectService to fetch relationships and query metadata.

      Parameters:
      dataObjectService - the DataObjectService to inject

    • linkChanges

      public void linkChanges(Object rootObject, Set<String> changedPropertyPaths)
      Performs linking of references and keys for the given root object based on the given set of changed property paths that should be considered during the linking process.

      The root object should be non-null and also a valid data object (such that DataObjectService.supports(Class) returns true for it). If neither of these conditions is true, this method will return immediately.

      See class-level documentation for specifics on how the linking algorithm functions.

      Parameters:
      rootObject - the root object from which to perform the linking
      changedPropertyPaths - the set of property paths relative to the root object that should be considered modified by the linking algorithm

    • linkChangesInternal

      protected void linkChangesInternal(Object object, Map<String,Set<String>> changedPropertyPaths, Set<Object> linked)
      Internal implementation of link changes which is implemented to support recursion through the object graph.
      Parameters:
      object - the object from which to link
      changedPropertyPaths - a decomposed property path map where the key of the map is a direct property path relative to the given object and the values are the remainder of the path relative to the parent path, see decomposePropertyPaths(java.util.Set)
      linked - a set containing objects which have already been linked, used to prevent infinite recursion due to circular references

    • linkRelationshipChanges

      protected void linkRelationshipChanges(DataObjectWrapper<?> wrapped, Map<String,Set<String>> decomposedPaths, Set<Object> linked)
      Link changes for relationships on the given wrapped data object.
      Parameters:
      wrapped - the wrapped data object
      decomposedPaths - the decomposed map of changed property paths
      linked - a set containing objects which have already been linked

    • linkCollectionChanges

      protected void linkCollectionChanges(DataObjectWrapper<?> wrapped, Map<String,Set<String>> decomposedPaths, Set<Object> linked)
      Link changes for collections on the given wrapped data object.
      Parameters:
      wrapped - the wrapped data object
      decomposedPaths - the decomposed map of changed property paths
      linked - a set containing objects which have already been linked

    • linkBiDirectionalCollection

      protected void linkBiDirectionalCollection(DataObjectWrapper<?> parentWrapper, DataObjectWrapper<?> elementWrapper, DataObjectCollection collectionMetadata)
      Performs bi-directional collection linking, ensuring that for bi-directional collection relationships that both sides of the relationship are properly populated.
      Parameters:
      parentWrapper - parent
      elementWrapper - element
      collectionMetadata - collection

    • isPrimaryKeyModified

      protected boolean isPrimaryKeyModified(DataObjectMetadata metadata, Set<String> modifiedPropertyPaths)
      Checks if primary key can be modified.
      Returns:
      whether primary key can be modified.

    • cascadeLinkingAnnotations

      protected void cascadeLinkingAnnotations(DataObjectWrapper<?> wrapped, Map<String,Set<String>> decomposedPaths, Set<Object> linked)
      Gets indexes that have been modified.

      Returns a list of cascade links in the field names that are also in the decomposed paths.

      Parameters:
      wrapped - used to get all field names.
      decomposedPaths - contains field names to be used.
      linked -

    • assembleLinkingPaths

      protected List<String> assembleLinkingPaths(Link link)
      Returns a list of link paths based on provided link.
      Parameters:
      link - used get paths from.
      Returns:
      list of paths

    • decomposePropertyPaths

      protected Map<String,Set<String>> decomposePropertyPaths(Set<String> changedPropertyPaths)
      Returns decomposed property paths based on changedPropertyPaths
      Parameters:
      changedPropertyPaths - changes to property paths
      Returns:
      map decomposed property paths with changedPropertyPaths

    • decomposePropertyPaths

      protected Map<String,Set<String>> decomposePropertyPaths(Set<String> changedPropertyPaths, String prefix)
      Returns decomposed property paths that start with the provide prefix
      Parameters:
      changedPropertyPaths - changes to property paths
      prefix - filter that paths must start with
      Returns:
      map decomposed property paths with changedPropertyPaths