Module java.desktop
Package javax.swing.text

# Class FlowView.FlowStrategy

java.lang.Object
javax.swing.text.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

## Constructor Summary

Constructors
Constructor
Description
`FlowStrategy()`
Constructs a `FlowStrategy`.

## Method Summary

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`

## Constructor Details

### FlowStrategy

public FlowStrategy()
Constructs a `FlowStrategy`.

## Method Details

### 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