ome.services.graphs

Class GraphTraversal

java.lang.Object

ome.services.graphs.GraphTraversal

public class GraphTraversal
extends Object

An alternative implementation of model object graph traversal, relying on SELECTing in advance for making decisions, instead of rolling back to savepoints to recover from failed attempts to act.

Since:

5.1.0

Author:

m.t.b.carroll@dundee.ac.uk

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	GraphTraversal.PlanExecutor Executor that allows callers to actually perform the planned action.
static interface	GraphTraversal.Processor Executes the planned operation.

Constructor Summary

Constructors

Constructor and Description
GraphTraversal(org.hibernate.Session session, EventContext eventContext, ACLVoter aclVoter, SystemTypes systemTypes, GraphPathBean graphPathBean, com.google.common.collect.SetMultimap<String,String> unnullable, GraphPolicy policy, GraphTraversal.Processor processor) Construct a new instance of a graph traversal manager.

Method Summary

Modifier and Type	Method and Description
void	assertNoPolicyViolations() Check that there are no policy violations matched by p:error policy rules.
void	assertNoUnlinking() Assert that unlinkTargets(boolean) need not be called.
com.google.common.collect.SetMultimap<String,Long>	getLinkeds(String propertyValueClass, String propertyName, Long id) Get the model objects that are linked to by the given object via the given property.
com.google.common.collect.SetMultimap<String,Long>	getLinkers(String propertyValueClass, String propertyName, Long id) Get the model objects that link to the given object via the given property.
Map.Entry<Collection<IObject>,Collection<IObject>>	planOperation(org.hibernate.Session session, Collection<? extends IObject> objectInstances, boolean include, boolean applyRules) Traverse model object graph to determine steps for the proposed operation.
Map.Entry<com.google.common.collect.SetMultimap<String,Long>,com.google.common.collect.SetMultimap<String,Long>>	planOperation(org.hibernate.Session session, com.google.common.collect.SetMultimap<String,Long> objects, boolean include, boolean applyRules) Traverse model object graph to determine steps for the proposed operation.
GraphTraversal.PlanExecutor	processTargets() Prepare to process the targeted model objects.
GraphTraversal.PlanExecutor	unlinkTargets(boolean isUnlinkIncludeFromExclude) Prepare to remove links between the targeted model objects and the remainder of the model object graph.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

GraphTraversal

public GraphTraversal(org.hibernate.Session session,
                      EventContext eventContext,
                      ACLVoter aclVoter,
                      SystemTypes systemTypes,
                      GraphPathBean graphPathBean,
                      com.google.common.collect.SetMultimap<String,String> unnullable,
                      GraphPolicy policy,
                      GraphTraversal.Processor processor)

Construct a new instance of a graph traversal manager.

Parameters:

session - the Hibernate session

eventContext - the current event context

aclVoter - ACL voter for permissions checking

systemTypes - for identifying the system types

graphPathBean - the graph path bean

unnullable - properties that, while nullable, may not be nulled by a graph traversal operation

policy - how to determine which related objects to include in the operation

processor - how to operate on the resulting target object graph

Method Detail

planOperation

public Map.Entry<com.google.common.collect.SetMultimap<String,Long>,com.google.common.collect.SetMultimap<String,Long>> planOperation(org.hibernate.Session session,
                                                                                                                                      com.google.common.collect.SetMultimap<String,Long> objects,
                                                                                                                                      boolean include,
                                                                                                                                      boolean applyRules)
                                                                                                                               throws GraphException

Traverse model object graph to determine steps for the proposed operation.

Parameters:

session - the Hibernate session to use for HQL queries

objects - the model objects to process

include - if the given model objects are to be included (instead of just deleted)

applyRules - if the given model objects should have the policy rules applied to them

Returns:

the model objects included in the operation, and the deleted objects

Throws:

GraphException - if the model objects were not as expected

planOperation

public Map.Entry<Collection<IObject>,Collection<IObject>> planOperation(org.hibernate.Session session,
                                                                        Collection<? extends IObject> objectInstances,
                                                                        boolean include,
                                                                        boolean applyRules)
                                                                 throws GraphException

Traverse model object graph to determine steps for the proposed operation.

Parameters:

session - the Hibernate session to use for HQL queries

objectInstances - the model objects to process, may be unloaded with ID only

include - if the given model objects are to be included (instead of just deleted)

applyRules - if the given model objects should have the policy rules applied to them

Returns:

the model objects included in the operation, and the deleted objects, may be unloaded with ID only

Throws:

GraphException - if the model objects were not as expected

assertNoPolicyViolations

public void assertNoPolicyViolations()
                              throws GraphException

Check that there are no policy violations matched by p:error policy rules.

Throws:

GraphException - if the policy rules are violated

assertNoUnlinking

public void assertNoUnlinking()
                       throws GraphException

Assert that unlinkTargets(boolean) need not be called.

Throws:

GraphException - if any model objects are to be GraphPolicy.Action.DELETEd

unlinkTargets

public GraphTraversal.PlanExecutor unlinkTargets(boolean isUnlinkIncludeFromExclude)
                                          throws GraphException

Prepare to remove links between the targeted model objects and the remainder of the model object graph.

Parameters:

isUnlinkIncludeFromExclude - if GraphPolicy.Action.EXCLUDE objects must be unlinked from GraphPolicy.Action.INCLUDE objects and vice versa

Returns:

the actual unlinker for the targeted model objects, to be used by the caller

Throws:

GraphException - if the user does not have permission to unlink the targets

processTargets

public GraphTraversal.PlanExecutor processTargets()
                                           throws GraphException

Prepare to process the targeted model objects.

Returns:

the actual processor for the targeted model objects, to be used by the caller

Throws:

GraphException - if the user does not have permission to process the targets or if a cycle is detected in the model object graph

getLinkeds

public com.google.common.collect.SetMultimap<String,Long> getLinkeds(String propertyValueClass,
                                                                     String propertyName,
                                                                     Long id)

Get the model objects that are linked to by the given object via the given property. Provides a window into the model object cache accumulated in planning a graph operation.

Parameters:

propertyValueClass - the full name of the model class that declares the given property

propertyName - a property name, may be nested

id - the ID of the model object doing the linking

Returns:

the class and ID of the model objects that are linked to by the given object, never null

getLinkers

public com.google.common.collect.SetMultimap<String,Long> getLinkers(String propertyValueClass,
                                                                     String propertyName,
                                                                     Long id)

Get the model objects that link to the given object via the given property. Provides a window into the model object cache accumulated in planning a graph operation.

Parameters:

propertyValueClass - the full name of the model class that declares the given property

propertyName - a property name, may be nested

id - the ID of the model object being linked to

Returns:

the class and ID of the model objects that link to the given object, never null