com.vaadin.data.


Interface Container.Hierarchical

All Superinterfaces:

Container, Serializable

All Known Subinterfaces:

Collapsible

All Known Implementing Classes:

ContainerHierarchicalWrapper, FilesystemContainer, HierarchicalContainer, HierarchicalContainerOrderedWrapper, Tree, TreeTable

Enclosing interface:

Container

public static interface Container.Hierarchical
extends Container

Interface for Container classes whose Items can be arranged hierarchically. This means that the Items in the container belong in a tree-like structure, with the following quirks:

  • The Item structure may have more than one root elements
  • The Items in the hierarchy can be declared explicitly to be able or unable to have children.

Nested Class Summary
 
Nested classes/interfaces inherited from interface com.vaadin.data.Container
Container.Editor, Container.Filter, Container.Filterable, Container.Hierarchical, Container.Indexed, Container.ItemSetChangeEvent, Container.ItemSetChangeListener, Container.ItemSetChangeNotifier, Container.Ordered, Container.PropertySetChangeEvent, Container.PropertySetChangeListener, Container.PropertySetChangeNotifier, Container.SimpleFilterable, Container.Sortable, Container.Viewer
 
Method Summary
 boolean areChildrenAllowed(Object itemId)
          Tests if the Item with given ID can have children.
 Collection<?> getChildren(Object itemId)
          Gets the IDs of all Items that are children of the specified Item.
 Object getParent(Object itemId)
          Gets the ID of the parent Item of the specified Item.
 boolean hasChildren(Object itemId)
           Tests if the Item specified with itemId has child Items or if it is a leaf.
 boolean isRoot(Object itemId)
          Tests if the Item specified with itemId is a root Item.
 boolean removeItem(Object itemId)
           Removes the Item identified by ItemId from the Container.
 Collection<?> rootItemIds()
          Gets the IDs of all Items in the container that don't have a parent.
 boolean setChildrenAllowed(Object itemId, boolean areChildrenAllowed)
           Sets the given Item's capability to have children.
 boolean setParent(Object itemId, Object newParentId)
           Sets the parent of an Item.
 
Methods inherited from interface com.vaadin.data.Container
addContainerProperty, addItem, addItem, containsId, getContainerProperty, getContainerPropertyIds, getItem, getItemIds, getType, removeAllItems, removeContainerProperty, size
 

Method Detail

getChildren

Collection<?> getChildren(Object itemId)

Gets the IDs of all Items that are children of the specified Item. The returned collection is unmodifiable.

Parameters:
itemId - ID of the Item whose children the caller is interested in
Returns:
An unmodifiable collection containing the IDs of all other Items that are children in the container hierarchy

getParent

Object getParent(Object itemId)

Gets the ID of the parent Item of the specified Item.

Parameters:
itemId - ID of the Item whose parent the caller wishes to find out.
Returns:
the ID of the parent Item. Will be null if the specified Item is a root element.

rootItemIds

Collection<?> rootItemIds()

Gets the IDs of all Items in the container that don't have a parent. Such items are called root Items. The returned collection is unmodifiable.

Returns:
An unmodifiable collection containing IDs of all root elements of the container

setParent

boolean setParent(Object itemId,
                  Object newParentId)
                  throws UnsupportedOperationException

Sets the parent of an Item. The new parent item must exist and be able to have children. ( areChildrenAllowed(Object) == true ). It is also possible to detach a node from the hierarchy (and thus make it root) by setting the parent null.

This operation is optional.

Parameters:
itemId - ID of the item to be set as the child of the Item identified with newParentId
newParentId - ID of the Item that's to be the new parent of the Item identified with itemId
Returns:
true if the operation succeeded, false if not
Throws:
UnsupportedOperationException

areChildrenAllowed

boolean areChildrenAllowed(Object itemId)

Tests if the Item with given ID can have children.

Parameters:
itemId - ID of the Item in the container whose child capability is to be tested
Returns:
true if the specified Item exists in the Container and it can have children, false if it's not found from the container or it can't have children.

setChildrenAllowed

boolean setChildrenAllowed(Object itemId,
                           boolean areChildrenAllowed)
                           throws UnsupportedOperationException

Sets the given Item's capability to have children. If the Item identified with itemId already has children and areChildrenAllowed(Object) is false this method fails and false is returned.

The children must be first explicitly removed with setParent(Object itemId, Object newParentId)or Container.removeItem(Object itemId).

This operation is optional. If it is not implemented, the method always returns false.

Parameters:
itemId - ID of the Item in the container whose child capability is to be set
areChildrenAllowed - boolean value specifying if the Item can have children or not
Returns:
true if the operation succeeded, false if not
Throws:
UnsupportedOperationException

isRoot

boolean isRoot(Object itemId)

Tests if the Item specified with itemId is a root Item. The hierarchical container can have more than one root and must have at least one unless it is empty. The getParent(Object itemId) method always returns null for root Items.

Parameters:
itemId - ID of the Item whose root status is to be tested
Returns:
true if the specified Item is a root, false if not

hasChildren

boolean hasChildren(Object itemId)

Tests if the Item specified with itemId has child Items or if it is a leaf. The getChildren(Object itemId) method always returns null for leaf Items.

Note that being a leaf does not imply whether or not an Item is allowed to have children.

.

Parameters:
itemId - ID of the Item to be tested
Returns:
true if the specified Item has children, false if not (is a leaf)

removeItem

boolean removeItem(Object itemId)
                   throws UnsupportedOperationException

Removes the Item identified by ItemId from the Container.

Note that this does not remove any children the item might have.

Specified by:
removeItem in interface Container

Parameters:
itemId - ID of the Item to remove
Returns:
true if the operation succeeded, false if not
Throws:
UnsupportedOperationException - if the container does not support removing individual items