Class FlowView.FlowStrategy

Enclosing class:
FlowView
public static class FlowView.FlowStrategy
extends Object

Strategy for maintaining the physical form of the flow. The default implementation is completely stateless, and recalculates the entire flow if the layout is invalid on the given FlowView. Alternative strategies can be implemented by subclassing, and might perform incremental repair to the layout or alternative breaking behavior.

Since:
1.3

Constructors

Constructor Description
FlowStrategy()

Methods

Modifier and Type Method Description
protected void adjustRow​(FlowView fv, int rowIndex, int desiredSpan, int x)

Adjusts the given row if possible to fit within the layout span.
void changedUpdate​(FlowView fv, DocumentEvent e, Rectangle alloc)

Gives notification from the document that attributes were changed in a location that this view is responsible for.
protected View createView​(FlowView fv, int startOffset, int spanLeft, int rowIndex)

Creates a view that can be used to represent the current piece of the flow.
protected View getLogicalView​(FlowView fv)

This method gives flow strategies access to the logical view of the FlowView.
void insertUpdate​(FlowView fv, DocumentEvent e, Rectangle alloc)

Gives notification that something was inserted into the document in a location that the given flow view is responsible for.
void layout​(FlowView fv)

Update the flow on the given FlowView.
protected int layoutRow​(FlowView fv, int rowIndex, int pos)

Creates a row of views that will fit within the layout span of the row.
void removeUpdate​(FlowView fv, DocumentEvent e, Rectangle alloc)

Gives notification that something was removed from the document in a location that the given flow view is responsible for.

Methods declared in class java.lang.Object

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

Constructors

FlowStrategy

public FlowStrategy()

Methods

insertUpdate

public void insertUpdate(FlowView fv,
                         DocumentEvent e,
                         Rectangle alloc)

Gives notification that something was inserted into the document in a location that the given flow view is responsible for. The strategy should update the appropriate changed region (which depends upon the strategy used for repair).

Parameters:
fv - the flow view
e - the change information from the associated document
alloc - the current allocation of the view inside of the insets. This value will be null if the view has not yet been displayed.
See Also:
View.insertUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

removeUpdate

public void removeUpdate(FlowView fv,
                         DocumentEvent e,
                         Rectangle alloc)

Gives notification that something was removed from the document in a location that the given flow view is responsible for.

Parameters:
fv - the flow view
e - the change information from the associated document
alloc - the current allocation of the view inside of the insets.
See Also:
View.removeUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

changedUpdate

public void changedUpdate(FlowView fv,
                          DocumentEvent e,
                          Rectangle alloc)

Gives notification from the document that attributes were changed in a location that this view is responsible for.

Parameters:
fv - the FlowView containing the changes
e - the DocumentEvent describing the changes done to the Document
alloc - Bounds of the View
See Also:
View.changedUpdate(javax.swing.event.DocumentEvent, java.awt.Shape, javax.swing.text.ViewFactory)

getLogicalView

protected View getLogicalView(FlowView fv)

This method gives flow strategies access to the logical view of the FlowView.

Parameters:
fv - the FlowView
Returns:
the logical view of the FlowView

layout

public void layout(FlowView fv)

Update the flow on the given FlowView. By default, this causes all of the rows (child views) to be rebuilt to match the given constraints for each row. This is called by a FlowView.layout to update the child views in the flow.

Parameters:
fv - the view to reflow

layoutRow

protected int layoutRow(FlowView fv,
                        int rowIndex,
                        int pos)

Creates a row of views that will fit within the layout span of the row. This is called by the layout method. This is implemented to fill the row by repeatedly calling the createView method until the available span has been exhausted, a forced break was encountered, or the createView method returned null. If the remaining span was exhausted, the adjustRow method will be called to perform adjustments to the row to try and make it fit into the given span.

Parameters:
fv - the flow view
rowIndex - the index of the row to fill in with views. The row is assumed to be empty on entry.
pos - The current position in the children of this views element from which to start.
Returns:
the position to start the next row

adjustRow

protected void adjustRow(FlowView fv,
                         int rowIndex,
                         int desiredSpan,
                         int x)

Adjusts the given row if possible to fit within the layout span. By default this will try to find the highest break weight possible nearest the end of the row. If a forced break is encountered, the break will be positioned there.

Parameters:
fv - the flow view
rowIndex - the row to adjust to the current layout span.
desiredSpan - the current layout span >= 0
x - the location r starts at.

createView

protected View createView(FlowView fv,
                          int startOffset,
                          int spanLeft,
                          int rowIndex)

Creates a view that can be used to represent the current piece of the flow. This can be either an entire view from the logical view, or a fragment of the logical view.

Parameters:
fv - the view holding the flow
startOffset - the start location for the view being created
spanLeft - the about of span left to fill in the row
rowIndex - the row the view will be placed into
Returns:
a view that can be used to represent the current piece of the flow

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https://docs.oracle.com/en/java/javase/11/docs/api/java.desktop/javax/swing/text/FlowView.FlowStrategy.html