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Version: Java (Groovy)

tree

The Deephaven tree method creates a tree table from a source table given an ID column name and parent column name.

Syntax​

resultNoOrphans = source.tree(idColumn, parentColumn)
resultWithOrphans = TreeTable.promoteOrphans(source, idColumn, parentColumn).tree(idColumn, parentColumn)

Parameters​

ParameterTypeDescription
idColumn>String

The name of the ID column.

parentColumnString

The name of the parent column.

Methods​

Static​

The TreeTable interface has the following static methods:

Instance​

The following methods can be called on an instance of TreeTable:

  • getIdentifierColumn - Get the name of the identifier column used to create the tree table.
  • getNodeDefinition - Get the TableDefinition that should be exposed to node table consumers.
  • getParentIdentifierColumn - Get the name of the parent identifier column used to create the tree table.
  • makeNodeOperationsRecorder - Create a TreeNodeOperationsRecorder, which records node-level operations when capturing snapshots.
  • withFilters(filters...) - Create a new TreeTable with the specified Filters applied.
  • withNodeFilterColumns(ColumnNames...) - Create a new TreeTable with the specified ColumnNames... designated for node-level filtering.
  • withNodeOperations(nodeOperations) - Create a new TreeTable that will apply the recorded operations to nodes when gathering snapshots.

Returns​

A tree table.

Examples​

The following example creates a tree table from a static table.

source = emptyTable(100).updateView("ID = i", "Parent = i == 0 ? NULL_INT : (int)(i / 4)")

result = source.tree("ID", "Parent")

The following example creates a tree table from a real-time table.

t1 = emptyTable(10_000).updateView("ID = i", "Parent = i == 0 ? NULL_INT : (int)(i / 10)")
t2 = timeTable("PT00:00:00.01").updateView("I = i % 10_000").lastBy("I")

source = t1.join(t2, "ID = I")

result = source.tree("ID", "Parent")

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The following example contains orphan nodes. Two tree tables are created. The first omits orphan nodes, while the second promotes them such that they appear in the tree table.

import io.deephaven.engine.table.hierarchical.TreeTable

source = emptyTable(100).updateView("ID = i + 2", "Parent = i == 0 ? NULL_INT : i % 100")

resultNoOrphans = source.tree("ID", "Parent")
resultWithOrphans = TreeTable.promoteOrphans(source, "ID", "Parent").tree("ID", "Parent")