Module java.desktop
Package javax.swing.text

Class CompositeView

java.lang.Object
javax.swing.text.View
javax.swing.text.CompositeView
All Implemented Interfaces:
SwingConstants
Direct Known Subclasses:
BoxView
public abstract class CompositeView extends View
CompositeView is an abstract View implementation which manages one or more child views. (Note that CompositeView is intended for managing relatively small numbers of child views.) CompositeView is intended to be used as a starting point for View implementations, such as BoxView, that will contain child Views. Subclasses that wish to manage the collection of child Views should use the replace(int, int, javax.swing.text.View[]) method. As View invokes replace during DocumentListener notification, you normally won't need to directly invoke replace.

While CompositeView does not impose a layout policy on its child Views, it does allow for inseting the child Views it will contain. The insets can be set by either setInsets(short, short, short, short) or setParagraphInsets(javax.swing.text.AttributeSet).

In addition to the abstract methods of View, subclasses of CompositeView will need to override:

  • Constructor Details

    • CompositeView

      public CompositeView(Element elem)
      Constructs a CompositeView for the given element.
      Parameters:
      elem - the element this view is responsible for

  • Method Details

    • loadChildren

      protected void loadChildren(ViewFactory f)
      Loads all of the children to initialize the view. This is called by the setParent(javax.swing.text.View) method. Subclasses can reimplement this to initialize their child views in a different manner. The default implementation creates a child view for each child element.
      Parameters:
      f - the view factory
      See Also:

    • setParent

      public void setParent(View parent)
      Sets the parent of the view. This is reimplemented to provide the superclass behavior as well as calling the loadChildren method if this view does not already have children. The children should not be loaded in the constructor because the act of setting the parent may cause them to try to search up the hierarchy (to get the hosting Container for example). If this view has children (the view is being moved from one place in the view hierarchy to another), the loadChildren method will not be called.
      Overrides:
      setParent in class View
      Parameters:
      parent - the parent of the view, null if none

    • getViewCount

      public int getViewCount()
      Returns the number of child views of this view.
      Overrides:
      getViewCount in class View
      Returns:
      the number of views >= 0
      See Also:

    • getView

      public View getView(int n)
      Returns the n-th view in this container.
      Overrides:
      getView in class View
      Parameters:
      n - the number of the desired view, >= 0 && < getViewCount()
      Returns:
      the view at index n

    • replace

      public void replace(int offset, int length, View[] views)
      Replaces child views. If there are no views to remove this acts as an insert. If there are no views to add this acts as a remove. Views being removed will have the parent set to null, and the internal reference to them removed so that they may be garbage collected.
      Overrides:
      replace in class View
      Parameters:
      offset - the starting index into the child views to insert the new views; >= 0 and <= getViewCount
      length - the number of existing child views to remove; this should be a value >= 0 and <= (getViewCount() - offset)
      views - the child views to add; this value can be null to indicate no children are being added (useful to remove)

    • getChildAllocation

      public Shape getChildAllocation(int index, Shape a)
      Fetches the allocation for the given child view to render into. This enables finding out where various views are located.
      Overrides:
      getChildAllocation in class View
      Parameters:
      index - the index of the child, >= 0 && < getViewCount()
      a - the allocation to this view
      Returns:
      the allocation to the child

    • modelToView

      public Shape modelToView(int pos, Shape a, Position.Bias b) throws BadLocationException
      Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.
      Specified by:
      modelToView in class View
      Parameters:
      pos - the position to convert >= 0
      a - the allocated region to render into
      b - a bias value of either Position.Bias.Forward or Position.Bias.Backward
      Returns:
      the bounding box of the given position
      Throws:
      BadLocationException - if the given position does not represent a valid location in the associated document
      See Also:

    • modelToView

      public Shape modelToView(int p0, Position.Bias b0, int p1, Position.Bias b1, Shape a) throws BadLocationException
      Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it.
      Overrides:
      modelToView in class View
      Parameters:
      p0 - the position to convert >= 0
      b0 - the bias toward the previous character or the next character represented by p0, in case the position is a boundary of two views; either Position.Bias.Forward or Position.Bias.Backward
      p1 - the position to convert >= 0
      b1 - the bias toward the previous character or the next character represented by p1, in case the position is a boundary of two views
      a - the allocated region to render into
      Returns:
      the bounding box of the given position is returned
      Throws:
      BadLocationException - if the given position does not represent a valid location in the associated document
      IllegalArgumentException - for an invalid bias argument
      See Also:

    • viewToModel

      public int viewToModel(float x, float y, Shape a, Position.Bias[] bias)
      Provides a mapping from the view coordinate space to the logical coordinate space of the model.
      Specified by:
      viewToModel in class View
      Parameters:
      x - x coordinate of the view location to convert >= 0
      y - y coordinate of the view location to convert >= 0
      a - the allocated region to render into
      bias - either Position.Bias.Forward or Position.Bias.Backward
      Returns:
      the location within the model that best represents the given point in the view >= 0
      See Also:

    • getNextVisualPositionFrom

      public int getNextVisualPositionFrom(int pos, Position.Bias b, Shape a, int direction, Position.Bias[] biasRet) throws BadLocationException
      Provides a way to determine the next visually represented model location that one might place a caret. Some views may not be visible, they might not be in the same order found in the model, or they just might not allow access to some of the locations in the model. This is a convenience method for getNextNorthSouthVisualPositionFrom(int, javax.swing.text.Position.Bias, java.awt.Shape, int, javax.swing.text.Position.Bias[]) and getNextEastWestVisualPositionFrom(int, javax.swing.text.Position.Bias, java.awt.Shape, int, javax.swing.text.Position.Bias[]). This method enables specifying a position to convert within the range of >=0. If the value is -1, a position will be calculated automatically. If the value < -1, the BadLocationException will be thrown.
      Overrides:
      getNextVisualPositionFrom in class View
      Parameters:
      pos - the position to convert
      b - a bias value of either Position.Bias.Forward or Position.Bias.Backward
      a - the allocated region to render into
      direction - the direction from the current position that can be thought of as the arrow keys typically found on a keyboard; this may be one of the following:
      • SwingConstants.WEST
      • SwingConstants.EAST
      • SwingConstants.NORTH
      • SwingConstants.SOUTH
      biasRet - an array containing the bias that was checked
      Returns:
      the location within the model that best represents the next location visual position
      Throws:
      BadLocationException - the given position is not a valid position within the document
      IllegalArgumentException - if direction is invalid

    • getViewIndex

      public int getViewIndex(int pos, Position.Bias b)
      Returns the child view index representing the given position in the model. This is implemented to call the getViewIndexByPosition method for backward compatibility.
      Overrides:
      getViewIndex in class View
      Parameters:
      pos - the position >= 0
      b - the bias
      Returns:
      index of the view representing the given position, or -1 if no view represents that position
      Since:
      1.3

    • isBefore

      protected abstract boolean isBefore(int x, int y, Rectangle alloc)
      Tests whether a point lies before the rectangle range.
      Parameters:
      x - the X coordinate >= 0
      y - the Y coordinate >= 0
      alloc - the rectangle
      Returns:
      true if the point is before the specified range

    • isAfter

      protected abstract boolean isAfter(int x, int y, Rectangle alloc)
      Tests whether a point lies after the rectangle range.
      Parameters:
      x - the X coordinate >= 0
      y - the Y coordinate >= 0
      alloc - the rectangle
      Returns:
      true if the point is after the specified range

    • getViewAtPoint

      protected abstract View getViewAtPoint(int x, int y, Rectangle alloc)
      Fetches the child view at the given coordinates.
      Parameters:
      x - the X coordinate >= 0
      y - the Y coordinate >= 0
      alloc - the parent's allocation on entry, which should be changed to the child's allocation on exit
      Returns:
      the child view

    • childAllocation

      protected abstract void childAllocation(int index, Rectangle a)
      Returns the allocation for a given child.
      Parameters:
      index - the index of the child, >= 0 && < getViewCount()
      a - the allocation to the interior of the box on entry, and the allocation of the child view at the index on exit.

    • getViewAtPosition

      protected View getViewAtPosition(int pos, Rectangle a)
      Fetches the child view that represents the given position in the model. This is implemented to fetch the view in the case where there is a child view for each child element.
      Parameters:
      pos - the position >= 0
      a - the allocation to the interior of the box on entry, and the allocation of the view containing the position on exit
      Returns:
      the view representing the given position, or null if there isn't one

    • getViewIndexAtPosition

      protected int getViewIndexAtPosition(int pos)
      Fetches the child view index representing the given position in the model. This is implemented to fetch the view in the case where there is a child view for each child element.
      Parameters:
      pos - the position >= 0
      Returns:
      index of the view representing the given position, or -1 if no view represents that position

    • getInsideAllocation

      protected Rectangle getInsideAllocation(Shape a)
      Translates the immutable allocation given to the view to a mutable allocation that represents the interior allocation (i.e. the bounds of the given allocation with the top, left, bottom, and right insets removed. It is expected that the returned value would be further mutated to represent an allocation to a child view. This is implemented to reuse an instance variable so it avoids creating excessive Rectangles. Typically the result of calling this method would be fed to the childAllocation method.
      Parameters:
      a - the allocation given to the view
      Returns:
      the allocation that represents the inside of the view after the margins have all been removed; if the given allocation was null, the return value is null

    • setParagraphInsets

      protected void setParagraphInsets(AttributeSet attr)
      Sets the insets from the paragraph attributes specified in the given attributes.
      Parameters:
      attr - the attributes

    • setInsets

      protected void setInsets(short top, short left, short bottom, short right)
      Sets the insets for the view.
      Parameters:
      top - the top inset >= 0
      left - the left inset >= 0
      bottom - the bottom inset >= 0
      right - the right inset >= 0

    • getLeftInset

      protected short getLeftInset()
      Gets the left inset.
      Returns:
      the inset >= 0

    • getRightInset

      protected short getRightInset()
      Gets the right inset.
      Returns:
      the inset >= 0

    • getTopInset

      protected short getTopInset()
      Gets the top inset.
      Returns:
      the inset >= 0

    • getBottomInset

      protected short getBottomInset()
      Gets the bottom inset.
      Returns:
      the inset >= 0

    • getNextNorthSouthVisualPositionFrom

      protected int getNextNorthSouthVisualPositionFrom(int pos, Position.Bias b, Shape a, int direction, Position.Bias[] biasRet) throws BadLocationException
      Returns the next visual position for the cursor, in either the north or south direction.
      Parameters:
      pos - the position to convert >= 0
      b - a bias value of either Position.Bias.Forward or Position.Bias.Backward
      a - the allocated region to render into
      direction - the direction from the current position that can be thought of as the arrow keys typically found on a keyboard; this may be one of the following:
      • SwingConstants.NORTH
      • SwingConstants.SOUTH
      biasRet - an array containing the bias that was checked
      Returns:
      the location within the model that best represents the next north or south location
      Throws:
      BadLocationException - for a bad location within a document model
      IllegalArgumentException - if direction is invalid
      See Also:

    • getNextEastWestVisualPositionFrom

      protected int getNextEastWestVisualPositionFrom(int pos, Position.Bias b, Shape a, int direction, Position.Bias[] biasRet) throws BadLocationException
      Returns the next visual position for the cursor, in either the east or west direction.
      Parameters:
      pos - the position to convert >= 0
      b - a bias value of either Position.Bias.Forward or Position.Bias.Backward
      a - the allocated region to render into
      direction - the direction from the current position that can be thought of as the arrow keys typically found on a keyboard; this may be one of the following:
      • SwingConstants.WEST
      • SwingConstants.EAST
      biasRet - an array containing the bias that was checked
      Returns:
      the location within the model that best represents the next west or east location
      Throws:
      BadLocationException - for a bad location within a document model
      IllegalArgumentException - if direction is invalid
      See Also:

    • flipEastAndWestAtEnds

      protected boolean flipEastAndWestAtEnds(int position, Position.Bias bias)
      Determines in which direction the next view lays. Consider the View at index n. Typically the Views are layed out from left to right, so that the View to the EAST will be at index n + 1, and the View to the WEST will be at index n - 1. In certain situations, such as with bidirectional text, it is possible that the View to EAST is not at index n + 1, but rather at index n - 1, or that the View to the WEST is not at index n - 1, but index n + 1. In this case this method would return true, indicating the Views are layed out in descending order.

      This unconditionally returns false, subclasses should override this method if there is the possibility for laying Views in descending order.

      Parameters:
      position - position into the model
      bias - either Position.Bias.Forward or Position.Bias.Backward
      Returns:
      false