[CAY-1940] NullPointerException when try to Prefetch

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.2.M1
• Fix Version/s: 4.0.M3
• Component/s: Core Library, Database integration
• Environment: Ubuntu 14.04lts, Java 1.7, Mysql 5.5.37
• Assignee: Savva Kolbachev
• Reporter: Andrey
• Created: 09/Jul/14 08:20
• Updated: 12/Mar/15 12:55
• Resolved: 12/Mar/15 12:55

Description

Use case description:

Cayenne model:

Tables:
Contact
id -primary key
name - string
Course
id - primary key
name - string
Relation
id - primary key
entityIdentifier - entity name of related object
entityId - id of related object
ruleId - id of rule
Rule
id - primary key
name - string

Classes:
Contact
properties: id, name
relations: List< ContactRuleRelation> ruleRelations

Course
properties: id, name
relations: List< CourseRuleRelation > ruleRelations

RuleRelation
properties: id, entityIdentifier
relations: rule

ContactRuleRelation extends RuleRelation
(entityIdentifier = 'Contact')

CourseRuleRelation extends RuleRelation
(entityIdentifier = 'Course')

Rule
properties: id, name

Data in the database:
Contact: id=1, name=Contact1
Course: id=1, name=Course1
Relation: id=1, objectIdentifier=Course, objectID=1, ruleId=1
Rule: id=1, name=Rule1

SelectQuery:
select Contact by id = 1 and add prefetch relations.rule

As result the exception:

java.lang.NullPointerException
at org.apache.cayenne.access.ResultScanParentAttachmentStrategy.indexParents(ResultScanParentAttachmentStrategy.java:104)
at org.apache.cayenne.access.ResultScanParentAttachmentStrategy.linkToParent(ResultScanParentAttachmentStrategy.java:72)
at org.apache.cayenne.access.HierarchicalObjectResolverNode.objectsFromDataRows(HierarchicalObjectResolverNode.java:70)
at org.apache.cayenne.access.HierarchicalObjectResolver$DisjointProcessor.startDisjointPrefetch(HierarchicalObjectResolver.java:121)
at org.apache.cayenne.query.PrefetchTreeNode.traverse(PrefetchTreeNode.java:206)
at org.apache.cayenne.query.PrefetchTreeNode.traverse(PrefetchTreeNode.java:221)
at org.apache.cayenne.query.PrefetchTreeNode.traverse(PrefetchTreeNode.java:221)
at org.apache.cayenne.access.HierarchicalObjectResolver.resolveObjectTree(HierarchicalObjectResolver.java:96)
at org.apache.cayenne.access.HierarchicalObjectResolver.synchronizedRootResultNodeFromDataRows(HierarchicalObjectResolver.java:78)
at org.apache.cayenne.access.DataDomainQueryAction$ObjectConversionStrategy.toResultsTree(DataDomainQueryAction.java:565)
at org.apache.cayenne.access.DataDomainQueryAction$SingleObjectConversionStrategy.convert(DataDomainQueryAction.java:603)
at org.apache.cayenne.access.DataDomainQueryAction.interceptObjectConversion(DataDomainQueryAction.java:459)
at org.apache.cayenne.access.DataDomainQueryAction.execute(DataDomainQueryAction.java:129)
at org.apache.cayenne.access.DataDomain.onQueryNoFilters(DataDomain.java:605)
at org.apache.cayenne.access.DataDomain$DataDomainQueryFilterChain.onQuery(DataDomain.java:838)

Looks like Cayenne considers only entityId without entityIdentifier when try to load the prefetch.