Learning > presentation > hierarchies > Node Artifacts Rule

Node Artifacts Rule

Based on NodeArtifactsRule interface.

Node artifacts rules are used to create and assign artifacts to specific nodes. The artifacts can be accessed when evaluating parent node's hideExpression to decide whether it should be hidden or not.

Typical Use Case

The hierarchy consists of Subject nodes and each Subject may or may not have child Model nodes. There are 2 types of Models: A & B, we want ModelA nodes to be visible and ModelB ones to be hidden. We want Subject node to be visible only if it has a Model (either A or B).

Problem

In this case we can't use hideIfNoChildren flag on Subjects, because a Subject node may only have a related ModelB which means Subject doesn't have children and should be displayed as a leaf node.

Solution

Use NodeArtifacts on the ModelB nodes and a hideExpression on Subject nodes. The expression can access artifacts created by child ModelB nodes: NOT ThisNode.HasChildren AND NOT ThisNode.ChildrenArtifacts.AnyMatches(x => x.IsModelB).

Attributes

Name	Required?	Type	Default	Meaning
Filtering
`requiredSchemas`	No	`RequiredSchemaSpecification[]`	`[]`	Specifications that define schema requirements for the rule to take effect.
`priority`	No	`number`	`1000`	Defines the order in which presentation rules are evaluated.
`onlyIfNotHandled`	No	`boolean`	`false`	Should this rule be ignored if there is already an existing rule with a higher priority.
`condition`	No	ECExpression	`""`	Defines a condition for the rule, which needs to be met in order to execute it.
Artifacts
`items`	No	`{ [key: string]: ECExpression }`		A map of ECExpressions whose evaluation results are used as artifact values

Example

{
  "ruleType": "NodeArtifacts",
  "priority": 999,
  "requiredSchemas": [{ "name": "MySchema", "minVersion": "1.2.3" }],
  "condition": "ThisNode.IsOfClass(\"MyClass\", \"MySchema\")",
  "items": {
    "isSpecialItem": "this.IsSpecial"
  }
}

Additional Notes

Warning: The rule is costly performance-wise and should only be used in very limited amount of specific cases where hidden child nodes need to be used to used to determine parent node's visibility.

Last Updated: 12 June, 2024