AsyncBoxView.ChildState (Java Platform SE 8 )
Keywords: javax.swing.text.AsyncBoxView.ChildState class
Date: 2016-04-24

javax.swing.text

## Class AsyncBoxView.ChildState

- java.lang.Object
- - javax.swing.text.AsyncBoxView.ChildState

- All Implemented Interfaces:
    Runnable
  Enclosing class:
    AsyncBoxView

      public class AsyncBoxView.ChildState
      extends Object
      implements Runnable

  A record representing the layout state of a child view. It is runnable as a task on another thread. All access to the child view that is based upon a read-lock on the model should synchronize on this object (i.e. The layout thread and the GUI thread can both have a read lock on the model at the same time and are not protected from each other). Access to a child view hierarchy is serialized via synchronization on the ChildState instance.
  Since:
    1.3

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `ChildState(View v)` Construct a child status.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `View` | `getChildView()` Fetch the child view this record represents
    `float` | `getMajorOffset()` Get the offset along the major axis
    `float` | `getMajorSpan()` What is the span along the major axis.
    `float` | `getMinorOffset()` What is the offset along the minor axis
    `float` | `getMinorSpan()` What is the span along the minor axis.
    `boolean` | `isLayoutValid()` Has the child view been laid out.
    `void` | `preferenceChanged(boolean width, boolean height)` Mark preferences changed for this child.
    `void` | `run()` Update the child state.
    `void` | `setMajorOffset(float offs)` This method should only be called by the ChildLocator, it is simply a convenient place to hold the cached location.

    - ### Methods inherited from class java.lang.Object

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

- - ### Constructor Detail

    - #### ChildState

          public ChildState(View v)

      Construct a child status. This needs to start out as fairly large so we don't falsely begin with the idea that all of the children are visible.
      Since:
        1.4

  - ### Method Detail

    - #### getChildView

          public View getChildView()

      Fetch the child view this record represents

    - #### run

          public void run()

      Update the child state. This should be called by the thread that desires to spend time updating the child state (intended to be the layout thread).

      This acquires a read lock on the associated document for the duration of the update to ensure the model is not changed while it is operating. The first thing to do would be to see if any work actually needs to be done. The following could have conceivably happened while the state was waiting to be updated:

      1. The child may have been removed from the view hierarchy.
      2. The child may have been updated by a higher priority operation (i.e. the child may have become visible).
      Specified by:
        `run` in interface `Runnable`
      See Also:
        `Thread.run()`

    - #### getMinorSpan

          public float getMinorSpan()

      What is the span along the minor axis.

    - #### getMinorOffset

          public float getMinorOffset()

      What is the offset along the minor axis

    - #### getMajorSpan

          public float getMajorSpan()

      What is the span along the major axis.

    - #### getMajorOffset

          public float getMajorOffset()

      Get the offset along the major axis

    - #### setMajorOffset

          public void setMajorOffset(float offs)

      This method should only be called by the ChildLocator, it is simply a convenient place to hold the cached location.

    - #### preferenceChanged

          public void preferenceChanged(boolean width,
                                        boolean height)

      Mark preferences changed for this child.
      Parameters:
        `width` - true if the width preference has changed
        `height` - true if the height preference has changed
      See Also:
        `JComponent.revalidate()`

    - #### isLayoutValid

          public boolean isLayoutValid()

      Has the child view been laid out.

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