Module org.apache.sis.util

Package org.apache.sis.util.collection

Interface TreeTable

All Known Implementing Classes:

Default­Tree­Table

public interface TreeTable

Defines the structure (list of columns) of a table and provides the root of the tree containing the data. Tree­Table can be seen as a table in which the first column contains a tree. Every row in this table is a Tree­Table.Node instance, and each node can have an arbitrary number of children nodes.

Below is an example of what a two-columns Tree­Table instance may look like when formatted as a text:

   Citation
     ├─Title…………………………………………………………… Open Geospatial Consortium
     ├─Presentation Forms………………………… document digital
     ├─Cited Responsible Parties
     │   ├─Organisation Name………………… Open Geospatial Consortium
     │   ├─Role…………………………………………………… resource provider
     │   └─Contact Info
     │       └─Online Resource
     │           ├─Linkage……………………… https://www.ogc.org/
     │           └─Function…………………… information
     └─Identifiers
         └─Code…………………………………………………… OGC

In many cases, the columns are known in advance as hard-coded static constants. Those column constants are typically documented close to the class producing the Tree­Table instance. Using directly those static constants provides type safety, as in the following example:

TreeTable table = ...;                   // Put here a TreeTable instance.
TreeTable.Node node = table.getRoot();
CharSequence   name = node.getValue(TableColumn.NAME);
Class<?>       type = node.getValue(TableColumn.TYPE);

In the above example, the type of value returned by the Tree­Table.Node.get­Value(Table­Column) method is determined by the column constant. However, this approach is possible only when the table structure is known in advance. If a method needs to work with arbitrary tables, then that method can get the list of columns by a call to get­Columns(). However this column list does not provide the above type-safety.

Since:

0.3

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	Tree­Table.Node	A node in a tree combined with a row in a table.

Method Summary

Modifier and Type	Method	Description
List<Table­Column<?>>	get­Columns()	Returns the table columns, in the order they shall be rendered by default.
Tree­Table.Node	get­Root()	Returns the root node of the tree.

Method Details

getColumns

List<TableColumn<?>> getColumns()

Returns the table columns, in the order they shall be rendered by default. This method returns the union of all table columns in every nodes of this tree. However, any Tree­Table.Node instance can return null for a particular column if the node doesn't have that column.

Returns:

the union of all table columns in every tree node.

See Also:

• Tree­Table.Node.get­Value(Table­Column)
• Tree­Table.Node.set­Value(Table­Column, Object)

getRoot

TreeTable.Node getRoot()

Returns the root node of the tree.

Returns:

the root node of the tree.