javax.swing.text.ZoneView
ZoneView is a View implementation that creates zones for which the child views are not created or stored until they are needed for display or model/view translations. This enables a substantial reduction in memory consumption for situations where the model being represented is very large, by building view objects only for the region being actively viewed/edited. The size of the children can be estimated in some way, or calculated asynchronously with only the result being saved.
ZoneView extends BoxView to provide a box that implements zones for its children. The zones are special View implementations (the children of an instance of this class) that represent only a portion of the model that an instance of ZoneView is responsible for. The zones don't create child views until an attempt is made to display them. A box shaped view is well suited to this because:
Boxes are a heavily used view, and having a box that provides this behavior gives substantial opportunity to plug the behavior into a view hierarchy from the view factory.
Boxes are tiled in one direction, so it is easy to divide them into zones in a reliable way.
Boxes typically have a simple relationship to the model (i.e. they create child views that directly represent the child elements).
Boxes are easier to estimate the size of than some other shapes.
The default behavior is controlled by two properties, maxZoneSize and maxZonesLoaded. Setting maxZoneSize to Integer.MAX_VALUE would have the effect of causing only one zone to be created. This would effectively turn the view into an implementation of the decorator pattern. Setting maxZonesLoaded to a value of Integer.MAX_VALUE would cause zones to never be unloaded. For simplicity, zones are created on boundaries represented by the child elements of the element the view is responsible for. The zones can be any View implementation, but the default implementation is based upon AsyncBoxView which supports fairly large zones efficiently.
ZoneView is a View implementation that creates zones for which the child views are not created or stored until they are needed for display or model/view translations. This enables a substantial reduction in memory consumption for situations where the model being represented is very large, by building view objects only for the region being actively viewed/edited. The size of the children can be estimated in some way, or calculated asynchronously with only the result being saved. ZoneView extends BoxView to provide a box that implements zones for its children. The zones are special View implementations (the children of an instance of this class) that represent only a portion of the model that an instance of ZoneView is responsible for. The zones don't create child views until an attempt is made to display them. A box shaped view is well suited to this because: Boxes are a heavily used view, and having a box that provides this behavior gives substantial opportunity to plug the behavior into a view hierarchy from the view factory. Boxes are tiled in one direction, so it is easy to divide them into zones in a reliable way. Boxes typically have a simple relationship to the model (i.e. they create child views that directly represent the child elements). Boxes are easier to estimate the size of than some other shapes. The default behavior is controlled by two properties, maxZoneSize and maxZonesLoaded. Setting maxZoneSize to Integer.MAX_VALUE would have the effect of causing only one zone to be created. This would effectively turn the view into an implementation of the decorator pattern. Setting maxZonesLoaded to a value of Integer.MAX_VALUE would cause zones to never be unloaded. For simplicity, zones are created on boundaries represented by the child elements of the element the view is responsible for. The zones can be any View implementation, but the default implementation is based upon AsyncBoxView which supports fairly large zones efficiently.
->zone-viewclj
(->zone-view elem axis)Constructor.
Constructs a ZoneView.
elem - the element this view is responsible for - javax.swing.text.Element
axis - either View.X_AXIS or View.Y_AXIS - int
Constructor. Constructs a ZoneView. elem - the element this view is responsible for - `javax.swing.text.Element` axis - either View.X_AXIS or View.Y_AXIS - `int`
get-max-zones-loadedclj
(get-max-zones-loaded this)Get the current setting of the number of zones allowed to be loaded at the same time.
returns: int
Get the current setting of the number of zones allowed to be loaded at the same time. returns: `int`
get-maximum-zone-sizeclj
(get-maximum-zone-size this)Get the current maximum zone size.
returns: int
Get the current maximum zone size. returns: `int`
insert-updateclj
(insert-update this changes a f)Gives notification that something was inserted into the document in a location that this view is responsible for. This is largely delegated to the superclass, but is reimplemented to update the relevant zone (i.e. determine if a zone needs to be split into a set of 2 or more zones).
changes - the change information from the associated document - javax.swing.event.DocumentEvent
a - the current allocation of the view - java.awt.Shape
f - the factory to use to rebuild if the view has children - javax.swing.text.ViewFactory
Gives notification that something was inserted into the document in a location that this view is responsible for. This is largely delegated to the superclass, but is reimplemented to update the relevant zone (i.e. determine if a zone needs to be split into a set of 2 or more zones). changes - the change information from the associated document - `javax.swing.event.DocumentEvent` a - the current allocation of the view - `java.awt.Shape` f - the factory to use to rebuild if the view has children - `javax.swing.text.ViewFactory`
remove-updateclj
(remove-update this changes a f)Gives notification that something was removed from the document in a location that this view is responsible for. This is largely delegated to the superclass, but is reimplemented to update the relevant zones (i.e. determine if zones need to be removed or joined with another zone).
changes - the change information from the associated document - javax.swing.event.DocumentEvent
a - the current allocation of the view - java.awt.Shape
f - the factory to use to rebuild if the view has children - javax.swing.text.ViewFactory
Gives notification that something was removed from the document in a location that this view is responsible for. This is largely delegated to the superclass, but is reimplemented to update the relevant zones (i.e. determine if zones need to be removed or joined with another zone). changes - the change information from the associated document - `javax.swing.event.DocumentEvent` a - the current allocation of the view - `java.awt.Shape` f - the factory to use to rebuild if the view has children - `javax.swing.text.ViewFactory`
set-max-zones-loadedclj
(set-max-zones-loaded this mzl)Sets the current setting of the number of zones allowed to be loaded at the same time. This will throw an IllegalArgumentException if mzl is less than 1.
mzl - the desired maximum number of zones to be actively loaded, must be greater than 0 - int
throws: java.lang.IllegalArgumentException - if mzl is < 1
Sets the current setting of the number of zones allowed to be loaded at the same time. This will throw an IllegalArgumentException if mzl is less than 1. mzl - the desired maximum number of zones to be actively loaded, must be greater than 0 - `int` throws: java.lang.IllegalArgumentException - if mzl is < 1
set-maximum-zone-sizeclj
(set-maximum-zone-size this size)Set the desired maximum zone size. A zone may get larger than this size if a single child view is larger than this size since zones are formed on child view boundaries.
size - the number of characters the zone may represent before attempting to break the zone into a smaller size. - int
Set the desired maximum zone size. A zone may get larger than this size if a single child view is larger than this size since zones are formed on child view boundaries. size - the number of characters the zone may represent before attempting to break the zone into a smaller size. - `int`
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