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https://issues.apache.org/jira/browse/CAY-2880?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17922401#comment-17922401
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Nikita Timofeev commented on CAY-2880:
--------------------------------------
Hi [~soliax]. Unfortunately you are struggling with a bit complicated API.
Much more convenient way to add prefetches to the query is via
{{query.prefetch(String path, int semantics)}} method:
{code:java}
query.prefetch("example.test", PrefetchTreeNode.JOINT_PREFETCH_SEMANTICS)
.prefetch("example.test2",
PrefetchTreeNode.DISJOINT_PREFETCH_SEMANTICS);{code}
Alternatively, if you need to initialize all prefetches beforehand (like you
are using some generic helper methods), you could do it like this:
{code:java}
PrefetchTreeNode root = new PrefetchTreeNode();
PrefetchTreeNode prefetchTreeNode = root.addPath("example.test");
prefetchTreeNode.setSemantics(PrefetchTreeNode.JOINT_PREFETCH_SEMANTICS);
prefetchTreeNode.setPhantom(false);
prefetchTreeNode = root.addPath("example.test2");
prefetchTreeNode.setSemantics(PrefetchTreeNode.DISJOINT_PREFETCH_SEMANTICS);
prefetchTreeNode.setPhantom(false);
query.prefetch(root); {code}
Hope this helps!
> Unable to Set Name for Child Nodes in PrefetchTreeNode
> ------------------------------------------------------
>
> Key: CAY-2880
> URL: https://issues.apache.org/jira/browse/CAY-2880
> Project: Cayenne
> Issue Type: Bug
> Components: Core Library
> Affects Versions: 4.2.1
> Environment: Windows 11 Java 17
> Reporter: lallemand
> Priority: Major
> Fix For: 4.2.2
>
>
> *Description:*
> It is currently impossible to use child nodes for {{PrefetchTreeNode}}
> because the {{name}} variable cannot be set. This leads to an error when
> calling {{{}addChild(){}}}, making the intended functionality unusable.
> *Affected Code:*
> {code:java}
> PrefetchTreeNode prefetchTreeNode = new PrefetchTreeNode();
> // Prefetch 1
> PrefetchTreeNode childPrefetchTreeNode = new PrefetchTreeNode();
> childPrefetchTreeNode.addPath("example.test");
> childPrefetchTreeNode.setSemantics(PrefetchTreeNode.JOINT_PREFETCH_SEMANTICS);
> prefetchTreeNode.addChild(childPrefetchTreeNode);
> // Prefetch 2
> childPrefetchTreeNode = new PrefetchTreeNode();
> childPrefetchTreeNode.addPath("example.test2");
> childPrefetchTreeNode.setSemantics(PrefetchTreeNode.DISJOINT_PREFETCH_SEMANTICS);
> prefetchTreeNode.addChild(childPrefetchTreeNode);
> query.prefetch(prefetchTreeNode);
> ObjectContext context = BaseContext.getThreadObjectContext();
> List<?> items = context.performQuery(query); {code}
> *Cayenne* {{*addChild*}} *Function:*
> {code:java}
> public void addChild(PrefetchTreeNode child) {
> if (Util.isEmptyString(child.getName())) {
> throw new IllegalArgumentException("Child has no segmentPath: " +
> child);
> } else {
> if (child.getParent() != this) {
> child.getParent().removeChild(child.getName());
> child.parent = this;
> }
> if (this.children == null) {
> this.children = new ArrayList(4);
> }
> this.children.add(child);
> }
> } {code}
> *Issue:*
> The {{addChild}} function requires the child node to have a name. However:
> * The {{PrefetchTreeNode}} constructor that accepts a {{name}} is protected.
> * The {{name}} variable itself is protected and cannot be accessed
> externally.
> * There is no public setter method for {{{}name{}}}.
> As a result, it is impossible to set the name of a child node, making the
> {{addChild()}} method non-functional for child nodes.
> *Workaround:*
> None available at this time.
> *Suggested Fix:*
> * Provide a public constructor that allows setting the {{{}name{}}}.
> * Alternatively, add a public setter method for {{name}} to enable proper
> initialization of child nodes.
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