File	Doc	Category	Size	Date	Package
AsyncBoxView.java	API Doc	Java SE 6 API	42264	Tue Jun 10 00:26:56 BST 2008	javax.swing.text

AsyncBoxView

• java.lang.Object
  • javax.swing.text.View

Fields Summary
int	axis The major axis against which the children are tiled.
List	stats The children and their layout statistics.
float	majorSpan Current span along the major axis. This is also the value returned by getMinimumSize, getPreferredSize, and getMaximumSize along the major axis.
boolean	estimatedMajorSpan Is the span along the major axis estimated?
float	minorSpan Current span along the minor axis. This is what layout was done against (i.e. things are flexible in this direction).
protected ChildLocator	locator Object that manages the offsets of the children. All locking for management of child locations is on this object.
float	topInset
float	bottomInset
float	leftInset
float	rightInset
ChildState	minRequest
ChildState	prefRequest
boolean	majorChanged
boolean	minorChanged
Runnable	flushTask
ChildState	changing Child that is actively changing size. This often causes a preferenceChanged, so this is a cache to possibly speed up the marking the state. It also helps flag an opportunity to avoid adding to flush task to the layout queue.

Constructors Summary
public AsyncBoxView(Element elem, int axis) Construct a box view that does asynchronous layout. param elem the element of the model to represent param axis the axis to tile along. This can be either X_AXIS or Y_AXIS. super(elem); stats = new ArrayList(); this.axis = axis; locator = new ChildLocator(); flushTask = new FlushTask(); minorSpan = Short.MAX_VALUE; estimatedMajorSpan = false;

Methods Summary
protected javax.swing.text.AsyncBoxView$ChildState	createChildState(javax.swing.text.View v) New ChildState records are created through this method to allow subclasses the extend the ChildState records to do/hold more return new ChildState(v);
protected void	flushRequirementChanges() Publish the changes in preferences upward to the parent view. This is normally called by the layout thread. AbstractDocument doc = (AbstractDocument) getDocument(); try { doc.readLock(); View parent = null; boolean horizontal = false; boolean vertical = false; synchronized(this) { // perform tasks that iterate over the children while // preventing the collection from changing. synchronized(stats) { int n = getViewCount(); if ((n > 0) && (minorChanged || estimatedMajorSpan)) { LayoutQueue q = getLayoutQueue(); ChildState min = getChildState(0); ChildState pref = getChildState(0); float span = 0f; for (int i = 1; i < n; i++) { ChildState cs = getChildState(i); if (minorChanged) { if (cs.min > min.min) { min = cs; } if (cs.pref > pref.pref) { pref = cs; } } if (estimatedMajorSpan) { span += cs.getMajorSpan(); } } if (minorChanged) { minRequest = min; prefRequest = pref; } if (estimatedMajorSpan) { majorSpan = span; estimatedMajorSpan = false; majorChanged = true; } } } // message preferenceChanged if (majorChanged || minorChanged) { parent = getParent(); if (parent != null) { if (axis == X_AXIS) { horizontal = majorChanged; vertical = minorChanged; } else { vertical = majorChanged; horizontal = minorChanged; } } majorChanged = false; minorChanged = false; } } // propagate a preferenceChanged, using the // layout thread. if (parent != null) { parent.preferenceChanged(this, horizontal, vertical); // probably want to change this to be more exact. Component c = getContainer(); if (c != null) { c.repaint(); } } } finally { doc.readUnlock(); }
public float	getBottomInset() Get the bottom part of the margin around the view. return bottomInset;
public java.awt.Shape	getChildAllocation(int index, java.awt.Shape a) Fetches the allocation for the given child view. This enables finding out where various views are located, without assuming the views store their location. This returns null since the default is to not have any child views. param index the index of the child, >= 0 && < getViewCount() param a the allocation to this view. return the allocation to the child Shape ca = locator.getChildAllocation(index, a); return ca;
protected javax.swing.text.AsyncBoxView$ChildState	getChildState(int index) Fetch the object representing the layout state of of the child at the given index. param index the child index. This should be a value >= 0 and < getViewCount(). synchronized(stats) { if ((index >= 0) && (index < stats.size())) { return (ChildState) stats.get(index); } return null; }
protected boolean	getEstimatedMajorSpan() Is the major span currently estimated? since 1.4 return estimatedMajorSpan;
protected float	getInsetSpan(int axis) Fetch the span along an axis that is taken up by the insets. param axis the axis to determine the total insets along, either X_AXIS or Y_AXIS. since 1.4 float margin = (axis == X_AXIS) ? getLeftInset() + getRightInset() : getTopInset() + getBottomInset(); return margin;
protected javax.swing.text.LayoutQueue	getLayoutQueue() Fetch the queue to use for layout. return LayoutQueue.getDefaultQueue();
public float	getLeftInset() Get the left part of the margin around the view. return leftInset;
public int	getMajorAxis() Fetch the major axis (the axis the children are tiled along). This will have a value of either X_AXIS or Y_AXIS. return axis;
public float	getMaximumSpan(int axis) Determines the maximum span for this view along an axis. param axis may be either View.X_AXIS or View.Y_AXIS return the span the view would like to be rendered into >= 0. Typically the view is told to render into the span that is returned, although there is no guarantee. The parent may choose to resize or break the view. exception IllegalArgumentException for an invalid axis type if (axis == this.axis) { return getPreferredSpan(axis); } return Integer.MAX_VALUE;
public float	getMinimumSpan(int axis) Determines the minimum span for this view along an axis. param axis may be either View.X_AXIS or View.Y_AXIS return the span the view would like to be rendered into >= 0. Typically the view is told to render into the span that is returned, although there is no guarantee. The parent may choose to resize or break the view. exception IllegalArgumentException for an invalid axis type if (axis == this.axis) { return getPreferredSpan(axis); } if (minRequest != null) { View child = minRequest.getChildView(); return child.getMinimumSpan(axis); } // nothing is known about the children yet if (axis == X_AXIS) { return getLeftInset() + getRightInset() + 5; } else { return getTopInset() + getBottomInset() + 5; }
public int	getMinorAxis() Fetch the minor axis (the axis orthoginal to the tiled axis). This will have a value of either X_AXIS or Y_AXIS. return (axis == X_AXIS) ? Y_AXIS : X_AXIS;
public int	getNextVisualPositionFrom(int pos, javax.swing.text.Position$Bias b, java.awt.Shape a, int direction, javax.swing.text.Position$Bias[] biasRet) 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. param pos the position to convert >= 0 param a the allocated region to render into param 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 param biasRet an array contain the bias that was checked return the location within the model that best represents the next location visual position exception BadLocationException exception IllegalArgumentException if direction is invalid return Utilities.getNextVisualPositionFrom( this, pos, b, a, direction, biasRet);
public float	getPreferredSpan(int axis) Determines the preferred span for this view along an axis. param axis may be either View.X_AXIS or View.Y_AXIS return the span the view would like to be rendered into >= 0. Typically the view is told to render into the span that is returned, although there is no guarantee. The parent may choose to resize or break the view. exception IllegalArgumentException for an invalid axis type float margin = getInsetSpan(axis); if (axis == this.axis) { return majorSpan + margin; } if (prefRequest != null) { View child = prefRequest.getChildView(); return child.getPreferredSpan(axis) + margin; } // nothing is known about the children yet return margin + 30;
public float	getRightInset() Get the right part of the margin around the view. return rightInset;
float	getSpanOnAxis(int axis) Retrieves the size of the view along an axis. param axis may be either View.X_AXIS or View.Y_AXIS return the current span of the view along the given axis, >= 0 if (axis == getMajorAxis()) { return majorSpan; } return minorSpan;
public float	getTopInset() Get the top part of the margin around the view. return topInset;
public javax.swing.text.View	getView(int n) Gets the nth child view. Since there are no children by default, this returns null. param n the number of the view to get, >= 0 && < getViewCount() return the view ChildState cs = getChildState(n); if (cs != null) { return cs.getChildView(); } return null;
public int	getViewCount() Returns the number of views in this view. Since the default is to not be a composite view this returns 0. return the number of views >= 0 see View#getViewCount synchronized(stats) { return stats.size(); }
public int	getViewIndex(int pos, javax.swing.text.Position$Bias b) Returns the child view index representing the given position in the model. By default a view has no children so this is implemented to return -1 to indicate there is no valid child index for any position. param pos the position >= 0 return index of the view representing the given position, or -1 if no view represents that position since 1.3 return getViewIndexAtPosition(pos, b);
protected synchronized int	getViewIndexAtPosition(int pos, javax.swing.text.Position$Bias b) 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. param pos the position >= 0 return index of the view representing the given position, or -1 if no view represents that position boolean isBackward = (b == Position.Bias.Backward); pos = (isBackward) ? Math.max(0, pos - 1) : pos; Element elem = getElement(); return elem.getElementIndex(pos);
protected void	loadChildren(javax.swing.text.ViewFactory f) Loads all of the children to initialize the view. This is called by the setParent 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. Normally a write-lock is held on the Document while the children are being changed, which keeps the rendering and layout threads safe. The exception to this is when the view is initialized to represent an existing element (via this method), so it is synchronized to exclude preferenceChanged while we are initializing. param f the view factory see #setParent Element e = getElement(); int n = e.getElementCount(); if (n > 0) { View[] added = new View[n]; for (int i = 0; i < n; i++) { added[i] = f.create(e.getElement(i)); } replace(0, 0, added); }
protected synchronized void	majorRequirementChange(javax.swing.text.AsyncBoxView$ChildState cs, float delta) Requirements changed along the major axis. This is called by the thread doing layout for the given ChildState object when it has completed fetching the child views new preferences. Typically this would be the layout thread, but might be the event thread if it is trying to update something immediately (such as to perform a model/view translation). This is implemented to mark the major axis as having changed so that a future check to see if the requirements need to be published to the parent view will consider the major axis. If the span along the major axis is not estimated, it is updated by the given delta to reflect the incremental change. The delta is ignored if the major span is estimated. if (estimatedMajorSpan == false) { majorSpan += delta; } majorChanged = true;
protected synchronized void	minorRequirementChange(javax.swing.text.AsyncBoxView$ChildState cs) Requirements changed along the minor axis. This is called by the thread doing layout for the given ChildState object when it has completed fetching the child views new preferences. Typically this would be the layout thread, but might be the GUI thread if it is trying to update something immediately (such as to perform a model/view translation). minorChanged = true;
public java.awt.Shape	modelToView(int pos, java.awt.Shape a, javax.swing.text.Position$Bias b) Provides a mapping from the document model coordinate space to the coordinate space of the view mapped to it. param pos the position to convert >= 0 param a the allocated region to render into param b the bias toward the previous character or the next character represented by the offset, in case the position is a boundary of two views. return the bounding box of the given position is returned exception BadLocationException if the given position does not represent a valid location in the associated document exception IllegalArgumentException for an invalid bias argument see View#viewToModel int index = getViewIndex(pos, b); Shape ca = locator.getChildAllocation(index, a); // forward to the child view, and make sure we don't // interact with the layout thread by synchronizing // on the child state. ChildState cs = getChildState(index); synchronized (cs) { View cv = cs.getChildView(); Shape v = cv.modelToView(pos, ca, b); return v; }
public void	paint(java.awt.Graphics g, java.awt.Shape alloc) Render the view using the given allocation and rendering surface. This is implemented to determine whether or not the desired region to be rendered (i.e. the unclipped area) is up to date or not. If up-to-date the children are rendered. If not up-to-date, a task to build the desired area is placed on the layout queue as a high priority task. This keeps by event thread moving by rendering if ready, and postponing until a later time if not ready (since paint requests can be rescheduled). param g the rendering surface to use param alloc the allocated region to render into see View#paint synchronized (locator) { locator.setAllocation(alloc); locator.paintChildren(g); }
public synchronized void	preferenceChanged(javax.swing.text.View child, boolean width, boolean height) Child views can call this on the parent to indicate that the preference has changed and should be reconsidered for layout. This is reimplemented to queue new work on the layout thread. This method gets messaged from multiple threads via the children. param child the child view param width true if the width preference has changed param height true if the height preference has changed see javax.swing.JComponent#revalidate if (child == null) { getParent().preferenceChanged(this, width, height); } else { if (changing != null) { View cv = changing.getChildView(); if (cv == child) { // size was being changed on the child, no need to // queue work for it. changing.preferenceChanged(width, height); return; } } int index = getViewIndex(child.getStartOffset(), Position.Bias.Forward); ChildState cs = getChildState(index); cs.preferenceChanged(width, height); LayoutQueue q = getLayoutQueue(); q.addTask(cs); q.addTask(flushTask); }
public void	replace(int offset, int length, javax.swing.text.View[] views) Calls the superclass to update the child views, and updates the status records for the children. This is expected to be called while a write lock is held on the model so that interaction with the layout thread will not happen (i.e. the layout thread acquires a read lock before doing anything). param offset the starting offset into the child views >= 0 param length the number of existing views to replace >= 0 param views the child views to insert synchronized(stats) { // remove the replaced state records for (int i = 0; i < length; i++) { ChildState cs = (ChildState)stats.remove(offset); float csSpan = cs.getMajorSpan(); cs.getChildView().setParent(null); if (csSpan != 0) { majorRequirementChange(cs, -csSpan); } } // insert the state records for the new children LayoutQueue q = getLayoutQueue(); if (views != null) { for (int i = 0; i < views.length; i++) { ChildState s = createChildState(views[i]); stats.add(offset + i, s); q.addTask(s); } } // notify that the size changed q.addTask(flushTask); }
public void	setBottomInset(float i) Set the bottom part of the margin around the view. param i the value of the inset bottomInset = i;
protected void	setEstimatedMajorSpan(boolean isEstimated) Set the estimatedMajorSpan property that determines if the major span should be treated as being estimated. If this property is true, the value of setSize along the major axis will change the requirements along the major axis and incremental changes will be ignored until all of the children have been updated (which will cause the property to automatically be set to false). If the property is false the value of the majorSpan will be considered to be accurate and incremental changes will be added into the total as they are calculated. since 1.4 estimatedMajorSpan = isEstimated;
public void	setLeftInset(float i) Set the left part of the margin around the view. param i the value of the inset leftInset = i;
public void	setParent(javax.swing.text.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. param parent the parent of the view, null if none super.setParent(parent); if ((parent != null) && (getViewCount() == 0)) { ViewFactory f = getViewFactory(); loadChildren(f); }
public void	setRightInset(float i) Set the right part of the margin around the view. param i the value of the inset rightInset = i;
public void	setSize(float width, float height) Sets the size of the view. This should cause layout of the view if the view caches any layout information. Since the major axis is updated asynchronously and should be the sum of the tiled children the call is ignored for the major axis. Since the minor axis is flexible, work is queued to resize the children if the minor span changes. param width the width >= 0 param height the height >= 0 setSpanOnAxis(X_AXIS, width); setSpanOnAxis(Y_AXIS, height);
void	setSpanOnAxis(int axis, float span) Sets the size of the view along an axis. Since the major axis is updated asynchronously and should be the sum of the tiled children the call is ignored for the major axis. Since the minor axis is flexible, work is queued to resize the children if the minor span changes. param axis may be either View.X_AXIS or View.Y_AXIS param span the span to layout to >= 0 float margin = getInsetSpan(axis); if (axis == getMinorAxis()) { float targetSpan = span - margin; if (targetSpan != minorSpan) { minorSpan = targetSpan; // mark all of the ChildState instances as needing to // resize the child, and queue up work to fix them. int n = getViewCount(); if (n != 0) { LayoutQueue q = getLayoutQueue(); for (int i = 0; i < n; i++) { ChildState cs = getChildState(i); cs.childSizeValid = false; q.addTask(cs); } q.addTask(flushTask); } } } else { // along the major axis the value is ignored // unless the estimatedMajorSpan property is // true. if (estimatedMajorSpan) { majorSpan = span - margin; } }
public void	setTopInset(float i) Set the top part of the margin around the view. param i the value of the inset topInset = i;
protected void	updateLayout(javax.swing.event.DocumentEvent$ElementChange ec, javax.swing.event.DocumentEvent e, java.awt.Shape a) Update the layout in response to receiving notification of change from the model. This is implemented to note the change on the ChildLocator so that offsets of the children will be correctly computed. param ec changes to the element this view is responsible for (may be null if there were no changes). param e the change information from the associated document param a the current allocation of the view see #insertUpdate see #removeUpdate see #changedUpdate if (ec != null) { // the newly inserted children don't have a valid // offset so the child locator needs to be messaged // that the child prior to the new children has // changed size. int index = Math.max(ec.getIndex() - 1, 0); ChildState cs = getChildState(index); locator.childChanged(cs); }
public int	viewToModel(float x, float y, java.awt.Shape a, javax.swing.text.Position$Bias[] biasReturn) Provides a mapping from the view coordinate space to the logical coordinate space of the model. The biasReturn argument will be filled in to indicate that the point given is closer to the next character in the model or the previous character in the model. This is expected to be called by the GUI thread, holding a read-lock on the associated model. It is implemented to locate the child view and determine it's allocation with a lock on the ChildLocator object, and to call viewToModel on the child view with a lock on the ChildState object to avoid interaction with the layout thread. param x the X coordinate >= 0 param y the Y coordinate >= 0 param a the allocated region to render into return the location within the model that best represents the given point in the view >= 0. The biasReturn argument will be filled in to indicate that the point given is closer to the next character in the model or the previous character in the model. int pos; // return position int index; // child index to forward to Shape ca; // child allocation // locate the child view and it's allocation so that // we can forward to it. Make sure the layout thread // doesn't change anything by trying to flush changes // to the parent while the GUI thread is trying to // find the child and it's allocation. synchronized (locator) { index = locator.getViewIndexAtPoint(x, y, a); ca = locator.getChildAllocation(index, a); } // forward to the child view, and make sure we don't // interact with the layout thread by synchronizing // on the child state. ChildState cs = getChildState(index); synchronized (cs) { View v = cs.getChildView(); pos = v.viewToModel(x, y, ca, biasReturn); } return pos;