Package org.dellroad.stuff.vaadin24.grid

Class GridColumnScanner<T>

java.lang.Object

org.dellroad.stuff.vaadin24.grid.GridColumnScanner<T>

Type Parameters:

T - Java class to be introspected

public class GridColumnScanner<T>
extends Object

Scans a Java class hierarchy for @GridColumn annotated getter methods, allowing for declarative auto-generation of Grid.Columns.

See @GridColumn for an example of usage.

See Also:

• @GridColumn

Constructor Summary

Constructors

Constructor	Description
GridColumnScanner(Class<T> type)	Scan the given type and all super-types for @GridColumn annotations.
GridColumnScanner(GridColumnScanner<T> original)	Static information copy constructor.

Method Summary

Modifier and Type	Method	Description
static <T> Grid.Column<T>	addColumn(Grid<T> grid, String key, GridColumn annotation, String description, ValueProvider<T,?> valueProvider, boolean selfRendering)	Add and configure a single column to the given Grid.
void	addColumnsTo(Grid<?> grid)	Augment the given Grid with columns auto-generated from @GridColumn annotations.
boolean	addVisbilityMenuItems(Grid<?> grid, HasMenuItems menu)	Add menu items that enable/disable the visibility of individual columns for for which visibilityMenu() was true to the given menu.
Grid<T>	buildGrid()	Create a new Grid with columns generated from @GridColumn annotations.
static Grid<?>	currentGrid()	Obtain the Grid being configured in the current thread.
protected String	determineColumnKey(MethodAnnotationScanner<T,GridColumn>.MethodInfo methodInfo)	Determine the column key from the annotation.
Map<String,MethodAnnotationScanner<T,GridColumn>.MethodInfo>	getColumnMap()	Get the annotations found through introspection indexed by column key.
Class<T>	getType()	Get the type associated with this instance.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

GridColumnScanner

public GridColumnScanner(Class<T> type)

Scan the given type and all super-types for @GridColumn annotations.

Parameters:

type - Java type to be introspected for annotations

Throws:

IllegalArgumentException - if type is null

IllegalArgumentException - if a bean property name cannot be inferred from the name of a method that is annotated with no explicit column key

IllegalArgumentException - if type has multiple @GridColumn-annotated methods specifying the same column key

GridColumnScanner

public GridColumnScanner(GridColumnScanner<T> original)

Static information copy constructor.

Using this constructor is more efficient than repeatedly scanning the same classes for the same annotations.

Any modifications made to the Map returned from getColumnMap() are included.

Parameters:

original - original instance

Throws:

IllegalArgumentException - if original is null

Method Details

getType

public Class<T> getType()

Get the type associated with this instance.

Returns:

backing object type

getColumnMap

public Map<String,MethodAnnotationScanner<T,GridColumn>.MethodInfo> getColumnMap()

Get the annotations found through introspection indexed by column key.

This represents static information gathered by this instance by scanning the class hierarchy during construction.

The returned map is mutable, e.g., if you delete unwanted entries then buildGrid() will skip them.

Returns:

annotations keyed by column key, and sorted based on GridColumn.order(), then key

buildGrid

public Grid<T> buildGrid()

Create a new Grid with columns generated from @GridColumn annotations.

No columns are included for bean properties that are not annotated.

During the execution of this method, in particular when any custom Renderer, ValueProvider, etc., classes are being instantiated, the Grid being configured is available via currentGrid().

Returns:

newly built Grid with auto-generated columns

addColumnsTo

public void addColumnsTo(Grid<?> grid)

Augment the given Grid with columns auto-generated from @GridColumn annotations.

This method applies to target Grids with any model type and gracefully handles mismatches: annotated methods declared in Java types that are not supertype of grid's model type always "return" null.

This allows populating a Grid with columns even when only some subtypes of the model type can actually provide values for those columns.

Any existing columns with conflicting column keys will be replaced.

During the execution of this method, in particular when any custom Renderer, ValueProvider, etc., classes are being instantiated, the supplied grid is available via currentGrid().

Parameters:

grid - target grid

Throws:

IllegalArgumentException - if grid is null

addVisbilityMenuItems

public boolean addVisbilityMenuItems(Grid<?> grid,
 HasMenuItems menu)

Add menu items that enable/disable the visibility of individual columns for for which visibilityMenu() was true to the given menu.

This method adds menu items for all columns in the given grid for which visibilityMenu() was true, according to the most recent call to buildGrid() or addColumnsTo().

The menu item labels come from header(), if any, otherwise key() via SharedUtil.camelCaseToHumanFriendly().

To use the menu, the caller will need to assign it to some target, e.g., via ContextMenuBase.setTarget(com.vaadin.flow.component.Component).

Parameters:

grid - grid containing previously scanned columns

menu - the menu to add visibility items to

Returns:

true if any menu items were added, otherwise false

Throws:

IllegalArgumentException - if either parameter is null

addColumn

public static <T> Grid.Column<T> addColumn(Grid<T> grid,
 String key,
 GridColumn annotation,
 String description,
 ValueProvider<T,?> valueProvider,
 boolean selfRendering)

Add and configure a single column to the given Grid.

During the execution of this method, in particular when any custom Renderer, ValueProvider, etc., classes are being instantiated, the supplied grid is available via currentGrid().

Type Parameters:

T - underlying bean type

Parameters:

grid - target Grid

key - the column's unique column key

annotation - @GridColumn annotation

description - description of what we're configuring (for debug purposes)

valueProvider - ValueProvider providing the return value from the annotated method, or null if ther annotated method returns or Void

selfRendering - true if the annotated method (and therefore valueProvider) returns a Component

Returns:

newly added column

Throws:

IllegalArgumentException - if any parameter is null

currentGrid

public static Grid<?> currentGrid()

Obtain the Grid being configured in the current thread.

This method only works when the current thread is executing in buildGrid(), addColumn(), or addColumnsTo().

Returns:

current Grid being configured

Throws:

IllegalStateException - if no Grid is currently being configured by this class

determineColumnKey

protected String determineColumnKey(MethodAnnotationScanner<T,GridColumn>.MethodInfo methodInfo)

Determine the column key from the annotation.

Parameters:

methodInfo - method info

Returns:

property name