FlowView.FlowStrategy (Java Platform SE 8 )
Keywords: javax.swing.text.FlowView.FlowStrategy class
Date: 2026-06-25

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 and Description
    `FlowStrategy()`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and 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 inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### FlowStrategy

          public FlowStrategy()

  - ### Method Detail

    - #### 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:
        `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:
        `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.

    - #### 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:
        `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:
        `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

Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Copyright © 1993, 2026, Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.