JavaTM 2 Platform
Std. Ed. v1.4.2

javax.swing.text
Class FlowView

java.lang.Object
  extended byjavax.swing.text.View
      extended byjavax.swing.text.CompositeView
          extended byjavax.swing.text.BoxView
              extended byjavax.swing.text.FlowView
All Implemented Interfaces:
SwingConstants
Direct Known Subclasses:
ParagraphView

public abstract class FlowView
extends BoxView

A View that tries to flow it's children into some partially constrained space. This can be used to build things like paragraphs, pages, etc. The flow is made up of the following pieces of functionality.

See Also:
View

Nested Class Summary
static class FlowView.FlowStrategy
          Strategy for maintaining the physical form of the flow.
 
Field Summary
protected  View layoutPool
          These are the views that represent the child elements of the element this view represents (The logical view to translate to a physical view).
protected  int layoutSpan
          Default constraint against which the flow is created against.
protected  FlowView.FlowStrategy strategy
          The behavior for keeping the flow updated.
 
Fields inherited from class javax.swing.text.View
BadBreakWeight, ExcellentBreakWeight, ForcedBreakWeight, GoodBreakWeight, X_AXIS, Y_AXIS
 
Fields inherited from interface javax.swing.SwingConstants
BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST
 
Constructor Summary
FlowView(Element elem, int axis)
          Constructs a FlowView for the given element.
 
Method Summary
protected  SizeRequirements calculateMinorAxisRequirements(int axis, SizeRequirements r)
          Calculate equirements along the minor axis.
 void changedUpdate(DocumentEvent changes, Shape a, ViewFactory f)
          Gives notification from the document that attributes were changed in a location that this view is responsible for.
protected abstract  View createRow()
          Create a View that should be used to hold a a rows worth of children in a flow.
 int getFlowAxis()
          Fetches the axis along which views should be flowed.
 int getFlowSpan(int index)
          Fetch the constraining span to flow against for the given child index.
 int getFlowStart(int index)
          Fetch the location along the flow axis that the flow span will start at.
protected  int getViewIndexAtPosition(int pos)
          Fetches the child view index representing the given position in the model.
 void insertUpdate(DocumentEvent changes, Shape a, ViewFactory f)
          Gives notification that something was inserted into the document in a location that this view is responsible for.
protected  void layout(int width, int height)
          Lays out the children.
protected  void loadChildren(ViewFactory f)
          Loads all of the children to initialize the view.
 void removeUpdate(DocumentEvent changes, Shape a, ViewFactory f)
          Gives notification that something was removed from the document in a location that this view is responsible for.
 
Methods inherited from class javax.swing.text.BoxView
baselineLayout, baselineRequirements, calculateMajorAxisRequirements, childAllocation, flipEastAndWestAtEnds, forwardUpdate, getAlignment, getAxis, getChildAllocation, getHeight, getMaximumSpan, getMinimumSpan, getOffset, getPreferredSpan, getResizeWeight, getSpan, getViewAtPoint, getWidth, isAfter, isAllocationValid, isBefore, isLayoutValid, layoutChanged, layoutMajorAxis, layoutMinorAxis, modelToView, paint, paintChild, preferenceChanged, replace, setAxis, setSize, viewToModel
 
Methods inherited from class javax.swing.text.CompositeView
getBottomInset, getInsideAllocation, getLeftInset, getNextEastWestVisualPositionFrom, getNextNorthSouthVisualPositionFrom, getNextVisualPositionFrom, getRightInset, getTopInset, getView, getViewAtPosition, getViewCount, getViewIndex, modelToView, setInsets, setParagraphInsets, setParent
 
Methods inherited from class javax.swing.text.View
append, breakView, createFragment, forwardUpdateToView, getAttributes, getBreakWeight, getContainer, getDocument, getElement, getEndOffset, getGraphics, getParent, getStartOffset, getToolTipText, getViewFactory, getViewIndex, insert, isVisible, modelToView, remove, removeAll, updateChildren, updateLayout, viewToModel
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

layoutSpan

protected int layoutSpan
Default constraint against which the flow is created against.


layoutPool

protected View layoutPool
These are the views that represent the child elements of the element this view represents (The logical view to translate to a physical view). These are not directly children of this view. These are either placed into the rows directly or used for the purpose of breaking into smaller chunks, to form the physical view.


strategy

protected FlowView.FlowStrategy strategy
The behavior for keeping the flow updated. By default this is a singleton shared by all instances of FlowView (FlowStrategy is stateless). Subclasses can create an alternative strategy, which might keep state.

Constructor Detail

FlowView

public FlowView(Element elem,
                int axis)
Constructs a FlowView for the given element.

Parameters:
elem - the element that this view is responsible for
axis - may be either View.X_AXIS or View.Y_AXIS
Method Detail

getFlowAxis

public int getFlowAxis()
Fetches the axis along which views should be flowed. By default, this will be the axis orthogonal to the axis along which the flow rows are tiled (the axis of the default flow rows themselves). This is typically used by the FlowStrategy.


getFlowSpan

public int getFlowSpan(int index)
Fetch the constraining span to flow against for the given child index. This is called by the FlowStrategy while it is updating the flow. A flow can be shaped by providing different values for the row constraints. By default, the entire span inside of the insets along the flow axis is returned.

Parameters:
index - the index of the row being updated. This should be a value >= 0 and < getViewCount().
See Also:
getFlowStart(int)

getFlowStart

public int getFlowStart(int index)
Fetch the location along the flow axis that the flow span will start at. This is called by the FlowStrategy while it is updating the flow. A flow can be shaped by providing different values for the row constraints.

Parameters:
index - the index of the row being updated. This should be a value >= 0 and < getViewCount().
See Also:
getFlowSpan(int)

createRow

protected abstract View createRow()
Create a View that should be used to hold a a rows worth of children in a flow. This is called by the FlowStrategy when new children are added or removed (i.e. rows are added or removed) in the process of updating the flow.


loadChildren

protected void loadChildren(ViewFactory f)
Loads all of the children to initialize the view. This is called by the setParent method. This is reimplemented to not load any children directly (as they are created in the process of formatting). If the layoutPool variable is null, an instance of LogicalView is created to represent the logical view that is used in the process of formatting.

Overrides:
loadChildren in class CompositeView
Parameters:
f - the view factory
See Also:
CompositeView.setParent(javax.swing.text.View)

getViewIndexAtPosition

protected int getViewIndexAtPosition(int pos)
Fetches the child view index representing the given position in the model.

Overrides:
getViewIndexAtPosition in class CompositeView
Parameters:
pos - the position >= 0
Returns:
index of the view representing the given position, or -1 if no view represents that position

layout

protected void layout(int width,
                      int height)
Lays out the children. If the span along the flow axis has changed, layout is marked as invalid which which will cause the superclass behavior to recalculate the layout along the box axis. The FlowStrategy.layout method will be called to rebuild the flow rows as appropriate. If the height of this view changes (determined by the perferred size along the box axis), a preferenceChanged is called. Following all of that, the normal box layout of the superclass is performed.

Overrides:
layout in class BoxView
Parameters:
width - the width to lay out against >= 0. This is the width inside of the inset area.
height - the height to lay out against >= 0 This is the height inside of the inset area.

calculateMinorAxisRequirements

protected SizeRequirements calculateMinorAxisRequirements(int axis,
                                                          SizeRequirements r)
Calculate equirements along the minor axis. This is implemented to forward the request to the logical view by calling getMinimumSpan, getPreferredSpan, and getMaximumSpan on it.

Overrides:
calculateMinorAxisRequirements in class BoxView
Parameters:
axis - the axis being studied
r - the SizeRequirements object; if null one will be created
Returns:
the newly initialized SizeRequirements object
See Also:
SizeRequirements

insertUpdate

public void insertUpdate(DocumentEvent changes,
                         Shape a,
                         ViewFactory f)
Gives notification that something was inserted into the document in a location that this view is responsible for.

Overrides:
insertUpdate in class View
Parameters:
changes - the change information from the associated document
a - the current allocation of the view
f - the factory to use to rebuild if the view has children
See Also:
View.insertUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

removeUpdate

public void removeUpdate(DocumentEvent changes,
                         Shape a,
                         ViewFactory f)
Gives notification that something was removed from the document in a location that this view is responsible for.

Overrides:
removeUpdate in class View
Parameters:
changes - the change information from the associated document
a - the current allocation of the view
f - the factory to use to rebuild if the view has children
See Also:
View.removeUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

changedUpdate

public void changedUpdate(DocumentEvent changes,
                          Shape a,
                          ViewFactory f)
Gives notification from the document that attributes were changed in a location that this view is responsible for.

Overrides:
changedUpdate in class View
Parameters:
changes - the change information from the associated document
a - the current allocation of the view
f - the factory to use to rebuild if the view has children
See Also:
View.changedUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

JavaTM 2 Platform
Std. Ed. v1.4.2

Submit a bug or feature
For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2003 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.


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