com.communote.common.menu

Class SimpleMenuBuilder<C extends MenuEntry,S extends MenuEntry>

java.lang.Object

com.communote.common.menu.SimpleMenuBuilder<C,S>

Type Parameters:

C - type of the categories

S - type of the sub-items

public class SimpleMenuBuilder<C extends MenuEntry,S extends MenuEntry>
extends Object

Builder to create a SimpleMenu with entries that are sorted according to a declarative defined position. This builder also supports a filtering mechanism to dynamically decide whether a certain category or category entry should be included in the menu.

Author:

Communote GmbH - http://www.communote.com/

Constructor Summary

Constructors

Constructor and Description
SimpleMenuBuilder()

Method Summary

Modifier and Type	Method and Description
boolean	addCategory(C item, PositionDescriptor positionDescriptor) Add a new category to the first level of the menu.
void	addCategoryEntryFilter(MenuEntryFilter<S> filter) Add a filter that will be called when the menu is built to decide whether a menu entry should be added to its category.
void	addCategoryFilter(MenuEntryFilter<C> filter) Add a filter that will be called when the menu is built to decide whether a category should be included in the menu.
boolean	addToCategory(String categoryId, S item, PositionDescriptor positionDescriptor) Add a menu item to a category.
SimpleMenu<C,S>	buildMenu() Create the final menu.
protected boolean	filterCategory(C category) Apply the registered category filters to the category and return whether it should be added to the menu
protected boolean	filterEntry(S entry) Apply the registered filters to the entry and return whether it should be added to the category.
C	getCategory(String categoryId) Get a category
S	getCategoryEntry(String categoryId, String entryId) Get a category entry.
protected boolean	isCachable() Denotes whether the built menu can be cached and should only be recreated if the menu content changed.
protected void	menuContentChanged() Is invoked if a category or category entry was added or removed.
boolean	removeCategory(C item) Remove a previously added category.
boolean	removeCategory(String categoryId) Same as removeCategory(C) but removes the category by its ID.
void	removeCategoryEntryFilter(MenuEntryFilter<S> filter) Remove a previously added filter
void	removeCategoryFilter(MenuEntryFilter<C> filter) Remove a previously added filter
S	removeFromCategory(String categoryId, S item) Remove a previously added item from a category.
S	removeFromCategory(String categoryId, String itemId) Same as removeFromCategory(String, S) but searches the item by its ID.

Methods inherited from class java.lang.Object

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

Constructor Detail

SimpleMenuBuilder

public SimpleMenuBuilder()

Method Detail

addCategory

public boolean addCategory(C item,
                           PositionDescriptor positionDescriptor)

Add a new category to the first level of the menu. If there is already a category with that ID the new one is ignored.

If called several times with position type TOP the categories which were added later will be positioned before those added earlier. If called several times with position type BOTTOM or AFTER (and the same menu entry ID to position after), the categories which were added later will be positioned after those added earlier. Entries with position type TOP are always before the BOTTOM positioned categories. Categories with position type AFTER will not appear in the resulting menu if the referenced category does not exist. However, if that referenced category is added later on, the categories to position after that category will than be contained in the menu.

Parameters:

item - the item to add

positionDescriptor - descriptor defining where the item should be added. If null the category will be added to the bottom.

Returns:

whether the category was added or there was already a category with the same ID

addCategoryEntryFilter

public void addCategoryEntryFilter(MenuEntryFilter<S> filter)

Add a filter that will be called when the menu is built to decide whether a menu entry should be added to its category.

Parameters:

filter - the filter to add

addCategoryFilter

public void addCategoryFilter(MenuEntryFilter<C> filter)

Add a filter that will be called when the menu is built to decide whether a category should be included in the menu.

Parameters:

filter - the filter to add

addToCategory

public boolean addToCategory(String categoryId,
                             S item,
                             PositionDescriptor positionDescriptor)

Add a menu item to a category. If the category does not exist the item won't be contained in the menu. But if the category is added later on this item will be added automatically to the category.

If called several times with position type TOP the entries which were added later will be positioned before those added earlier. If called several times with position type BOTTOM or AFTER (and the same menu entry ID to position after), the entries which were added later will be positioned after those added earlier. Entries with position type TOP are always before the BOTTOM positioned entries. Entries with position type AFTER will not appear in the resulting menu if the referenced menu entry does not exist. However, if that referenced entry is added later on, the entries to position after that entry will than be contained in the category.

Parameters:

categoryId - the ID of the category

item - the item to add

positionDescriptor - descriptor defining where the item should be added. If null the item will be added to the bottom

Returns:

whether the entry was added or there was already an entry with the same ID

buildMenu

public SimpleMenu<C,S> buildMenu()

Create the final menu. Should always be called after adding/removing categories or menu items because the children of a category are not directly updated.

Returns:

the created menu

filterCategory

protected boolean filterCategory(C category)

Apply the registered category filters to the category and return whether it should be added to the menu

Parameters:

category - the category to test

Returns:

true if the category should be included false otherwise

filterEntry

protected boolean filterEntry(S entry)

Apply the registered filters to the entry and return whether it should be added to the category.

Parameters:

entry - the entry to test

Returns:

true if the entry should be included false otherwise

getCategory

public C getCategory(String categoryId)

Get a category

Parameters:

categoryId - the ID of the category

Returns:

the category or null if there is no category for the given ID

getCategoryEntry

public S getCategoryEntry(String categoryId,
                          String entryId)

Get a category entry. This will even return an entry if the category of the entry was removed.

Parameters:

categoryId - the ID of the category

entryId - the ID of the entry in the category

Returns:

the entry or null if the entry was not added to a category with the given ID

isCachable

protected boolean isCachable()

Denotes whether the built menu can be cached and should only be recreated if the menu content changed.

This implementation assumes that registered filters lead to a menu that is not cacheable.

Returns:

true if the menu can be cached, false otherwise

menuContentChanged

protected void menuContentChanged()

Is invoked if a category or category entry was added or removed.

This implementation discards the cached menu.

removeCategory

public boolean removeCategory(C item)

Remove a previously added category. The items that were added to that category are not removed but will instead just not be in the resulting menu. If the category is added again the items will also be contained in the menu again.

Parameters:

item - the category to remove

Returns:

whether the category existed and was removed

removeCategory

public boolean removeCategory(String categoryId)

Same as removeCategory(C) but removes the category by its ID.

Parameters:

categoryId - the ID of the category to remove

Returns:

whether the category existed and was removed

removeCategoryEntryFilter

public void removeCategoryEntryFilter(MenuEntryFilter<S> filter)

Remove a previously added filter

Parameters:

filter - the filter to remove

removeCategoryFilter

public void removeCategoryFilter(MenuEntryFilter<C> filter)

Remove a previously added filter

Parameters:

filter - the filter to remove

removeFromCategory

public S removeFromCategory(String categoryId,
                            S item)

Remove a previously added item from a category.

Parameters:

categoryId - the ID of the category from which the entry should be removed

item - the item to remove

Returns:

the removed entry if the entry existed in the category, otherwise null

removeFromCategory

public S removeFromCategory(String categoryId,
                            String itemId)

Same as removeFromCategory(String, S) but searches the item by its ID.

Parameters:

categoryId - the ID of the category from which the entry should be removed

itemId - the ID of the item to remove

Returns:

the removed entry if the entry existed in the category, otherwise null