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public class: AsyncBoxView.ChildLocator [javadoc | source]
A class to manage the effective position of the child views in a localized area while changes are being made around the localized area. The AsyncBoxView may be continuously changing, but the visible area needs to remain fairly stable until the layout thread decides to publish an update to the parent.
Field Summary
protected  ChildState lastValidOffset    The location of the last offset calculation that is valid. 
protected  Rectangle lastAlloc    The last seen allocation (for repainting when changes are flushed upward). 
protected  Rectangle childAlloc    A shape to use for the child allocation to avoid creating a lot of garbage. 
 public ChildLocator() 
Method from javax.swing.text.AsyncBoxView$ChildLocator Summary:
childChanged,   getChildAllocation,   getChildAllocation,   getViewIndexAtPoint,   getViewIndexAtVisualOffset,   intersectsClip,   paintChildren,   setAllocation,   updateChildOffsets,   updateChildOffsetsToIndex
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from javax.swing.text.AsyncBoxView$ChildLocator Detail:
 public synchronized  void childChanged(ChildState cs) 
    Notification that a child changed. This can effect whether or not new offset calculations are needed. This is called by a ChildState object that has changed it's major span. This can therefore be called by multiple threads.
 protected Shape getChildAllocation(int index) 
    Fetch the allocation to use for a child view. This does not update the offsets in the ChildState records.
 public synchronized Shape getChildAllocation(int index,
    Shape a) 
    Fetch the allocation to use for a child view. This will update the offsets for all children not yet updated before the given index.
 public int getViewIndexAtPoint(float x,
    float y,
    Shape a) 
    Fetches the child view index at the given point. This is called by the various View methods that need to calculate which child to forward a message to. This should be called by a block synchronized on this object, and would typically be followed with one or more calls to getChildAllocation that should also be in the synchronized block.
 protected int getViewIndexAtVisualOffset(float targetOffset) 
    Locate the view responsible for an offset into the box along the major axis. Make sure that offsets are set on the ChildState objects up to the given target span past the desired offset.
 boolean intersectsClip(Shape childAlloc,
    Rectangle clip) 
 public synchronized  void paintChildren(Graphics g) 
    Paint the children that intersect the clip area.
 protected  void setAllocation(Shape a) 
    Copy the currently allocated shape into the Rectangle used to store the current allocation. This would be a floating point rectangle in a Java2D-specific implmentation.
 int updateChildOffsets(float targetOffset) 
    Move the location of the last offset calculation forward to the desired offset.
  void updateChildOffsetsToIndex(int index) 
    Move the location of the last offset calculation forward to the desired index.