Represents a view navigator. A view navigator provides access to all or a subset of the entries in a view.

Syntax

public class ViewNavigator extends Base

Containment

Contained by: View

Contains: ViewEntry

Properties

CacheSize through getCacheSize and setCacheSize

Count through getCount

MaxLevel through getMaxLevel and setMaxLevel

ParentView through getParentView

Methods

getChild

getCurrent

getFirst

getFirstDocument

getLast

getLastDocument

getNext

getNextCategory

getNextDocument

getNextSibling

getNth

getParent

getPos

getPrev

getPrevCategory

getPrevDocument

getPrevSibling

gotoChild

gotoEntry

gotoFirst

gotoFirstDocument

gotoLast

gotoLastDocument

gotoNext

gotoNextCategory

gotoNextDocument

gotoNextSibling

gotoParent

gotoPos

gotoPrev

gotoPrevCategory

gotoPrevDocument

gotoPrevSibling

markAllRead

markAllUnread

recycle

Creation

You create a view navigator through the following View methods:

• createViewNav
• createViewNavFrom
• createViewNavFromAllUnread
• createViewNavFromCategory
• createViewNavFromChildren
• createViewNavFromDescendants
• createViewNavMaxLevel

Usage

The ViewNavigator methods let you:

• Access categories and totals as well as documents.
• Access information specific to the view such as the number of siblings of a view entry.
• Subset the view.

A goto method is favored over a get method for navigation-only purposes because a goto method does not create a ViewEntry object.

In a categorized view, documents are children of categories.

If a view has totals, the grand total is considered a category entry, and getLast returns that entry. Subtotals are available in the columnValues of category entries.

A view navigator remains associated with the parent view. A refresh of the parent view affects the view navigator. However, if a view navigator is empty upon creation, it remains empty and refreshing the parent view has no effect.

For remote (IIOP) operations, ViewNavigator caches entries. Methods that navigate using the current pointer take advantage of the cache while methods that navigate relative to a specified entry do not take advantage of the cache. Refreshing the parent view causes a cache update. The cache is turned off if AutoUpdate is true for the parent view; caching is resumed if AutoUpdate is set to false. You can set the cache size and should set it to try to minimize server access.

Automatic updates: avoid

Avoid automatically updating the parent view by explicitly setting IsAutoUpdate to false. Automatic updates degrade performance and may invalidate entries in the navigator ("Entry not found in index"). You can update the view as needed with refresh.

Example
See Also

Java Classes A-Z
View navigators

Glossary