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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * accompanied this code).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
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package javax.swing.text;

import java.awt.*;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.SwingUtilities;
import javax.swing.event.*;


Component decorator that implements the view interface.  The
entire element is used to represent the component.  This acts
as a gateway from the display-only View implementations to
interactive lightweight components (ie it allows components
to be embedded into the View hierarchy).


The component is placed relative to the text baseline
according to the value returned by
Component.getAlignmentY.  For Swing components
this value can be conveniently set using the method
JComponent.setAlignmentY.  For example, setting
a value of 0.75 will cause 75 percent of the
component to be above the baseline, and 25 percent of the
component to be below the baseline.


This class is implemented to do the extra work necessary to
work properly in the presence of multiple threads (i.e. from
asynchronous notification of model changes for example) by
ensuring that all component access is done on the event thread.


The component used is determined by the return value of the
createComponent method.  The default implementation of this
method is to return the component held as an attribute of
the element (by calling StyleConstants.getComponent).  A
limitation of this behavior is that the component cannot
be used by more than one text component (i.e. with a shared
model).  Subclasses can remove this constraint by implementing
the createComponent to actually create a component based upon
some kind of specification contained in the attributes.  The
ObjectView class in the html package is an example of a
ComponentView implementation that supports multiple component
views of a shared model.

Author:Timothy Prinzing
/**
 * Component decorator that implements the view interface.  The
 * entire element is used to represent the component.  This acts
 * as a gateway from the display-only View implementations to
 * interactive lightweight components (ie it allows components
 * to be embedded into the View hierarchy).
 * <p>
 * The component is placed relative to the text baseline
 * according to the value returned by
 * <code>Component.getAlignmentY</code>.  For Swing components
 * this value can be conveniently set using the method
 * <code>JComponent.setAlignmentY</code>.  For example, setting
 * a value of <code>0.75</code> will cause 75 percent of the
 * component to be above the baseline, and 25 percent of the
 * component to be below the baseline.
 * <p>
 * This class is implemented to do the extra work necessary to
 * work properly in the presence of multiple threads (i.e. from
 * asynchronous notification of model changes for example) by
 * ensuring that all component access is done on the event thread.
 * <p>
 * The component used is determined by the return value of the
 * createComponent method.  The default implementation of this
 * method is to return the component held as an attribute of
 * the element (by calling StyleConstants.getComponent).  A
 * limitation of this behavior is that the component cannot
 * be used by more than one text component (i.e. with a shared
 * model).  Subclasses can remove this constraint by implementing
 * the createComponent to actually create a component based upon
 * some kind of specification contained in the attributes.  The
 * ObjectView class in the html package is an example of a
 * ComponentView implementation that supports multiple component
 * views of a shared model.
 *
 * @author Timothy Prinzing
 */
public class ComponentView extends View  {

    
Creates a new ComponentView object.

Params:
  • elem – the element to decorate
/**
     * Creates a new ComponentView object.
     *
     * @param elem the element to decorate
     */
    public ComponentView(Element elem) {
        super(elem);
    }

    
Create the component that is associated with
this view.  This will be called when it has
been determined that a new component is needed.
This would result from a call to setParent or
as a result of being notified that attributes
have changed.

/**
     * Create the component that is associated with
     * this view.  This will be called when it has
     * been determined that a new component is needed.
     * This would result from a call to setParent or
     * as a result of being notified that attributes
     * have changed.
     */
    protected Component createComponent() {
        AttributeSet attr = getElement().getAttributes();
        Component comp = StyleConstants.getComponent(attr);
        return comp;
    }

    
Fetch the component associated with the view.

/**
     * Fetch the component associated with the view.
     */
    public final Component getComponent() {
        return createdC;
    }

    // --- View methods ---------------------------------------------

    
The real paint behavior occurs naturally from the association
that the component has with its parent container (the same
container hosting this view).  This is implemented to do nothing.

Params:
  • g – the graphics context
  • a – the shape
See Also:
/**
     * The real paint behavior occurs naturally from the association
     * that the component has with its parent container (the same
     * container hosting this view).  This is implemented to do nothing.
     *
     * @param g the graphics context
     * @param a the shape
     * @see View#paint
     */
    public void paint(Graphics g, Shape a) {
        if (c != null) {
            Rectangle alloc = (a instanceof Rectangle) ?
                (Rectangle) a : a.getBounds();
            c.setBounds(alloc.x, alloc.y, alloc.width, alloc.height);
        }
    }

    
Determines the preferred span for this view along an
axis.  This is implemented to return the value
returned by Component.getPreferredSize along the
axis of interest.

Params:
  • axis – may be either View.X_AXIS or View.Y_AXIS
Throws:
Returns:  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.
/**
     * Determines the preferred span for this view along an
     * axis.  This is implemented to return the value
     * returned by Component.getPreferredSize along the
     * axis of interest.
     *
     * @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
     */
    public float getPreferredSpan(int axis) {
        if ((axis != X_AXIS) && (axis != Y_AXIS)) {
            throw new IllegalArgumentException("Invalid axis: " + axis);
        }
        if (c != null) {
            Dimension size = c.getPreferredSize();
            if (axis == View.X_AXIS) {
                return size.width;
            } else {
                return size.height;
            }
        }
        return 0;
    }

    
Determines the minimum span for this view along an
axis.  This is implemented to return the value
returned by Component.getMinimumSize along the
axis of interest.

Params:
  • axis – may be either View.X_AXIS or View.Y_AXIS
Throws:
Returns:  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.
/**
     * Determines the minimum span for this view along an
     * axis.  This is implemented to return the value
     * returned by Component.getMinimumSize along the
     * axis of interest.
     *
     * @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
     */
    public float getMinimumSpan(int axis) {
        if ((axis != X_AXIS) && (axis != Y_AXIS)) {
            throw new IllegalArgumentException("Invalid axis: " + axis);
        }
        if (c != null) {
            Dimension size = c.getMinimumSize();
            if (axis == View.X_AXIS) {
                return size.width;
            } else {
                return size.height;
            }
        }
        return 0;
    }

    
Determines the maximum span for this view along an
axis.  This is implemented to return the value
returned by Component.getMaximumSize along the
axis of interest.

Params:
  • axis – may be either View.X_AXIS or View.Y_AXIS
Throws:
Returns:  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.
/**
     * Determines the maximum span for this view along an
     * axis.  This is implemented to return the value
     * returned by Component.getMaximumSize along the
     * axis of interest.
     *
     * @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
     */
    public float getMaximumSpan(int axis) {
        if ((axis != X_AXIS) && (axis != Y_AXIS)) {
            throw new IllegalArgumentException("Invalid axis: " + axis);
        }
        if (c != null) {
            Dimension size = c.getMaximumSize();
            if (axis == View.X_AXIS) {
                return size.width;
            } else {
                return size.height;
            }
        }
        return 0;
    }

    
Determines the desired alignment for this view along an
axis.  This is implemented to give the alignment of the
embedded component.

Params:
  • axis – may be either View.X_AXIS or View.Y_AXIS
Returns:the desired alignment.  This should be a value
  between 0.0 and 1.0 where 0 indicates alignment at the
  origin and 1.0 indicates alignment to the full span
  away from the origin.  An alignment of 0.5 would be the
  center of the view.
/**
     * Determines the desired alignment for this view along an
     * axis.  This is implemented to give the alignment of the
     * embedded component.
     *
     * @param axis may be either View.X_AXIS or View.Y_AXIS
     * @return the desired alignment.  This should be a value
     *   between 0.0 and 1.0 where 0 indicates alignment at the
     *   origin and 1.0 indicates alignment to the full span
     *   away from the origin.  An alignment of 0.5 would be the
     *   center of the view.
     */
    public float getAlignment(int axis) {
        if (c != null) {
            switch (axis) {
            case View.X_AXIS:
                return c.getAlignmentX();
            case View.Y_AXIS:
                return c.getAlignmentY();
            }
        }
        return super.getAlignment(axis);
    }

    
Sets the parent for a child view.
The parent calls this on the child to tell it who its
parent is, giving the view access to things like
the hosting Container.  The superclass behavior is
executed, followed by a call to createComponent if
the parent view parameter is non-null and a component
has not yet been created. The embedded components parent
is then set to the value returned by getContainer.
If the parent view parameter is null, this view is being
cleaned up, thus the component is removed from its parent.


The changing of the component hierarchy will
touch the component lock, which is the one thing
that is not safe from the View hierarchy.  Therefore,
this functionality is executed immediately if on the
event thread, or is queued on the event queue if
called from another thread (notification of change
from an asynchronous update).

Params:
  • p – the parent
/**
     * Sets the parent for a child view.
     * The parent calls this on the child to tell it who its
     * parent is, giving the view access to things like
     * the hosting Container.  The superclass behavior is
     * executed, followed by a call to createComponent if
     * the parent view parameter is non-null and a component
     * has not yet been created. The embedded components parent
     * is then set to the value returned by <code>getContainer</code>.
     * If the parent view parameter is null, this view is being
     * cleaned up, thus the component is removed from its parent.
     * <p>
     * The changing of the component hierarchy will
     * touch the component lock, which is the one thing
     * that is not safe from the View hierarchy.  Therefore,
     * this functionality is executed immediately if on the
     * event thread, or is queued on the event queue if
     * called from another thread (notification of change
     * from an asynchronous update).
     *
     * @param p the parent
     */
    public void setParent(View p) {
        super.setParent(p);
        if (SwingUtilities.isEventDispatchThread()) {
            setComponentParent();
        } else {
            Runnable callSetComponentParent = new Runnable() {
                public void run() {
                    Document doc = getDocument();
                    try {
                        if (doc instanceof AbstractDocument) {
                            ((AbstractDocument)doc).readLock();
                        }
                        setComponentParent();
                        Container host = getContainer();
                        if (host != null) {
                            preferenceChanged(null, true, true);
                            host.repaint();
                        }
                    } finally {
                        if (doc instanceof AbstractDocument) {
                            ((AbstractDocument)doc).readUnlock();
                        }
                    }
                }
            };
            SwingUtilities.invokeLater(callSetComponentParent);
        }
    }

    
Set the parent of the embedded component
with assurance that it is thread-safe.

/**
     * Set the parent of the embedded component
     * with assurance that it is thread-safe.
     */
    void setComponentParent() {
        View p = getParent();
        if (p != null) {
            Container parent = getContainer();
            if (parent != null) {
                if (c == null) {
                    // try to build a component
                    Component comp = createComponent();
                    if (comp != null) {
                        createdC = comp;
                        c = new Invalidator(comp);
                    }
                }
                if (c != null) {
                    if (c.getParent() == null) {
                        // components associated with the View tree are added
                        // to the hosting container with the View as a constraint.
                        parent.add(c, this);
                        parent.addPropertyChangeListener("enabled", c);
                    }
                }
            }
        } else {
            if (c != null) {
                Container parent = c.getParent();
                if (parent != null) {
                    // remove the component from its hosting container
                    parent.remove(c);
                    parent.removePropertyChangeListener("enabled", c);
                }
            }
        }
    }

    
Provides a mapping from the coordinate space of the model to
that of the view.

Params:
  • pos – the position to convert >= 0
  • a – the allocated region to render into
Throws:
  • BadLocationException –  if the given position does not
  represent a valid location in the associated document
See Also:
Returns:the bounding box of the given position is returned
/**
     * Provides a mapping from the coordinate space of the model to
     * that of the view.
     *
     * @param pos the position to convert >= 0
     * @param a the allocated region to render into
     * @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
     * @see View#modelToView
     */
    public Shape modelToView(int pos, Shape a, Position.Bias b) throws BadLocationException {
        int p0 = getStartOffset();
        int p1 = getEndOffset();
        if ((pos >= p0) && (pos <= p1)) {
            Rectangle r = a.getBounds();
            if (pos == p1) {
                r.x += r.width;
            }
            r.width = 0;
            return r;
        }
        throw new BadLocationException(pos + " not in range " + p0 + "," + p1, pos);
    }

    
Provides a mapping from the view coordinate space to the logical
coordinate space of the model.

Params:
  • x – the X coordinate >= 0
  • y – the Y coordinate >= 0
  • a – the allocated region to render into
See Also:
Returns:the location within the model that best represents
   the given point in the view
/**
     * Provides a mapping from the view coordinate space to the logical
     * coordinate space of the model.
     *
     * @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
     * @see View#viewToModel
     */
    public int viewToModel(float x, float y, Shape a, Position.Bias[] bias) {
        Rectangle alloc = (Rectangle) a;
        if (x < alloc.x + (alloc.width / 2)) {
            bias[0] = Position.Bias.Forward;
            return getStartOffset();
        }
        bias[0] = Position.Bias.Backward;
        return getEndOffset();
    }

    // --- member variables ------------------------------------------------

    private Component createdC;
    private Invalidator c;

    
This class feeds the invalidate back to the
hosting View.  This is needed to get the View
hierarchy to consider giving the component
a different size (i.e. layout may have been
cached between the associated view and the
container hosting this component).

/**
     * This class feeds the invalidate back to the
     * hosting View.  This is needed to get the View
     * hierarchy to consider giving the component
     * a different size (i.e. layout may have been
     * cached between the associated view and the
     * container hosting this component).
     */
    class Invalidator extends Container implements PropertyChangeListener {

        // NOTE: When we remove this class we are going to have to some
        // how enforce setting of the focus traversal keys on the children
        // so that they don't inherit them from the JEditorPane. We need
        // to do this as JEditorPane has abnormal bindings (it is a focus cycle
        // root) and the children typically don't want these bindings as well.

        Invalidator(Component child) {
            setLayout(null);
            add(child);
            cacheChildSizes();
        }

        
The components invalid layout needs
to be propagated through the view hierarchy
so the views (which position the component)
can have their layout recomputed.

/**
         * The components invalid layout needs
         * to be propagated through the view hierarchy
         * so the views (which position the component)
         * can have their layout recomputed.
         */
        public void invalidate() {
            super.invalidate();
            if (getParent() != null) {
                preferenceChanged(null, true, true);
            }
        }

        public void doLayout() {
            cacheChildSizes();
        }

        public void setBounds(int x, int y, int w, int h) {
            super.setBounds(x, y, w, h);
            if (getComponentCount() > 0) {
                getComponent(0).setSize(w, h);
            }
            cacheChildSizes();
        }

        public void validateIfNecessary() {
            if (!isValid()) {
                validate();
             }
        }

        private void cacheChildSizes() {
            if (getComponentCount() > 0) {
                Component child = getComponent(0);
                min = child.getMinimumSize();
                pref = child.getPreferredSize();
                max = child.getMaximumSize();
                yalign = child.getAlignmentY();
                xalign = child.getAlignmentX();
            } else {
                min = pref = max = new Dimension(0, 0);
            }
        }

        
Shows or hides this component depending on the value of parameter
b.

See Also:
@paramb  If true, shows this component;
otherwise, hides this component.
Since:JDK1.1
/**
         * Shows or hides this component depending on the value of parameter
         * <code>b</code>.
         * @param <code>b</code>  If <code>true</code>, shows this component;
         * otherwise, hides this component.
         * @see #isVisible
         * @since JDK1.1
         */
        public void setVisible(boolean b) {
            super.setVisible(b);
            if (getComponentCount() > 0) {
                getComponent(0).setVisible(b);
            }
        }

        
Overridden to fix 4759054. Must return true so that content
is painted when inside a CellRendererPane which is normally
invisible.

/**
         * Overridden to fix 4759054. Must return true so that content
         * is painted when inside a CellRendererPane which is normally
         * invisible.
         */
        public boolean isShowing() {
            return true;
        }

        public Dimension getMinimumSize() {
            validateIfNecessary();
            return min;
        }

        public Dimension getPreferredSize() {
            validateIfNecessary();
            return pref;
        }

        public Dimension getMaximumSize() {
            validateIfNecessary();
            return max;
        }

        public float getAlignmentX() {
            validateIfNecessary();
            return xalign;
        }

        public float getAlignmentY() {
            validateIfNecessary();
            return yalign;
        }

        public java.util.Set getFocusTraversalKeys(int id) {
            return KeyboardFocusManager.getCurrentKeyboardFocusManager().
                    getDefaultFocusTraversalKeys(id);
        }

        public void propertyChange(PropertyChangeEvent ev) {
            Boolean enable = (Boolean) ev.getNewValue();
            if (getComponentCount() > 0) {
                getComponent(0).setEnabled(enable);
            }
        }

        Dimension min;
        Dimension pref;
        Dimension max;
        float yalign;
        float xalign;

    }

}