https://openjdk.java.net/ 
/*
 * Copyright (c) 1997, 2008, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package javax.swing.text;

import java.awt.*;
import java.util.*;
import java.io.*;

import javax.swing.SwingUtilities;
import javax.swing.event.ChangeListener;
import javax.swing.event.EventListenerList;
import javax.swing.event.ChangeEvent;
import java.lang.ref.WeakReference;
import java.util.WeakHashMap;

import sun.font.FontUtilities;


A pool of styles and their associated resources.  This class determines
the lifetime of a group of resources by being a container that holds
caches for various resources such as font and color that get reused
by the various style definitions.  This can be shared by multiple
documents if desired to maximize the sharing of related resources.


This class also provides efficient support for small sets of attributes
and compresses them by sharing across uses and taking advantage of
their immutable nature.  Since many styles are replicated, the potential
for sharing is significant, and copies can be extremely cheap.
Larger sets reduce the possibility of sharing, and therefore revert
automatically to a less space-efficient implementation.


Warning:
Serialized objects of this class will not be compatible with
future Swing releases. The current serialization support is
appropriate for short term storage or RMI between applications running
the same version of Swing.  As of 1.4, support for long term storage
of all JavaBeansTM
has been added to the java.beans package. Please see XMLEncoder. 
Author: Timothy Prinzing
/**
 * A pool of styles and their associated resources.  This class determines
 * the lifetime of a group of resources by being a container that holds
 * caches for various resources such as font and color that get reused
 * by the various style definitions.  This can be shared by multiple
 * documents if desired to maximize the sharing of related resources.
 * <p>
 * This class also provides efficient support for small sets of attributes
 * and compresses them by sharing across uses and taking advantage of
 * their immutable nature.  Since many styles are replicated, the potential
 * for sharing is significant, and copies can be extremely cheap.
 * Larger sets reduce the possibility of sharing, and therefore revert
 * automatically to a less space-efficient implementation.
 * <p>
 * <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with
 * future Swing releases. The current serialization support is
 * appropriate for short term storage or RMI between applications running
 * the same version of Swing.  As of 1.4, support for long term storage
 * of all JavaBeans<sup><font size="-2">TM</font></sup>
 * has been added to the <code>java.beans</code> package.
 * Please see {@link java.beans.XMLEncoder}.
 *
 * @author  Timothy Prinzing
 */
public class StyleContext implements Serializable, AbstractDocument.AttributeContext {

    
Returns default AttributeContext shared by all documents that
don't bother to define/supply their own context.

Returns:the context
/**
     * Returns default AttributeContext shared by all documents that
     * don't bother to define/supply their own context.
     *
     * @return the context
     */
    public static final StyleContext getDefaultStyleContext() {
        if (defaultContext == null) {
            defaultContext = new StyleContext();
        }
        return defaultContext;
    }

    private static StyleContext defaultContext;

    
Creates a new StyleContext object.

/**
     * Creates a new StyleContext object.
     */
    public StyleContext() {
        styles = new NamedStyle(null);
        addStyle(DEFAULT_STYLE, null);
    }

    
Adds a new style into the style hierarchy.  Style attributes
resolve from bottom up so an attribute specified in a child
will override an attribute specified in the parent.

Params:
  • nm –   the name of the style (must be unique within the
  collection of named styles in the document).  The name may
  be null if the style is unnamed, but the caller is responsible
  for managing the reference returned as an unnamed style can't
  be fetched by name.  An unnamed style may be useful for things
  like character attribute overrides such as found in a style
  run.
  • parent – the parent style.  This may be null if unspecified
  attributes need not be resolved in some other style.
Returns:the created style
/**
     * Adds a new style into the style hierarchy.  Style attributes
     * resolve from bottom up so an attribute specified in a child
     * will override an attribute specified in the parent.
     *
     * @param nm   the name of the style (must be unique within the
     *   collection of named styles in the document).  The name may
     *   be null if the style is unnamed, but the caller is responsible
     *   for managing the reference returned as an unnamed style can't
     *   be fetched by name.  An unnamed style may be useful for things
     *   like character attribute overrides such as found in a style
     *   run.
     * @param parent the parent style.  This may be null if unspecified
     *   attributes need not be resolved in some other style.
     * @return the created style
     */
    public Style addStyle(String nm, Style parent) {
        Style style = new NamedStyle(nm, parent);
        if (nm != null) {
            // add a named style, a class of attributes
            styles.addAttribute(nm, style);
        }
        return style;
    }

    
Removes a named style previously added to the document.

Params:
  • nm –  the name of the style to remove
/**
     * Removes a named style previously added to the document.
     *
     * @param nm  the name of the style to remove
     */
    public void removeStyle(String nm) {
        styles.removeAttribute(nm);
    }

    
Fetches a named style previously added to the document

Params:
  • nm –  the name of the style
Returns:the style
/**
     * Fetches a named style previously added to the document
     *
     * @param nm  the name of the style
     * @return the style
     */
    public Style getStyle(String nm) {
        return (Style) styles.getAttribute(nm);
    }

    
Fetches the names of the styles defined.

Returns:the list of names as an enumeration
/**
     * Fetches the names of the styles defined.
     *
     * @return the list of names as an enumeration
     */
    public Enumeration<?> getStyleNames() {
        return styles.getAttributeNames();
    }

    
Adds a listener to track when styles are added
or removed.

Params:
  • l – the change listener
/**
     * Adds a listener to track when styles are added
     * or removed.
     *
     * @param l the change listener
     */
    public void addChangeListener(ChangeListener l) {
        styles.addChangeListener(l);
    }

    
Removes a listener that was tracking styles being
added or removed.

Params:
  • l – the change listener
/**
     * Removes a listener that was tracking styles being
     * added or removed.
     *
     * @param l the change listener
     */
    public void removeChangeListener(ChangeListener l) {
        styles.removeChangeListener(l);
    }

    
Returns an array of all the ChangeListeners added
to this StyleContext with addChangeListener().

Returns:all of the ChangeListeners added or an empty
        array if no listeners have been added
Since:1.4
/**
     * Returns an array of all the <code>ChangeListener</code>s added
     * to this StyleContext with addChangeListener().
     *
     * @return all of the <code>ChangeListener</code>s added or an empty
     *         array if no listeners have been added
     * @since 1.4
     */
    public ChangeListener[] getChangeListeners() {
        return ((NamedStyle)styles).getChangeListeners();
    }

    
Gets the font from an attribute set.  This is
implemented to try and fetch a cached font
for the given AttributeSet, and if that fails
the font features are resolved and the
font is fetched from the low-level font cache.

Params:
  • attr – the attribute set
Returns:the font
/**
     * Gets the font from an attribute set.  This is
     * implemented to try and fetch a cached font
     * for the given AttributeSet, and if that fails
     * the font features are resolved and the
     * font is fetched from the low-level font cache.
     *
     * @param attr the attribute set
     * @return the font
     */
    public Font getFont(AttributeSet attr) {
        // PENDING(prinz) add cache behavior
        int style = Font.PLAIN;
        if (StyleConstants.isBold(attr)) {
            style |= Font.BOLD;
        }
        if (StyleConstants.isItalic(attr)) {
            style |= Font.ITALIC;
        }
        String family = StyleConstants.getFontFamily(attr);
        int size = StyleConstants.getFontSize(attr);

        /**
         * if either superscript or subscript is
         * is set, we need to reduce the font size
         * by 2.
         */
        if (StyleConstants.isSuperscript(attr) ||
            StyleConstants.isSubscript(attr)) {
            size -= 2;
        }

        return getFont(family, style, size);
    }

    
Takes a set of attributes and turn it into a foreground color
specification.  This might be used to specify things
like brighter, more hue, etc.  By default it simply returns
the value specified by the StyleConstants.Foreground attribute.

Params:
  • attr – the set of attributes
Returns:the color
/**
     * Takes a set of attributes and turn it into a foreground color
     * specification.  This might be used to specify things
     * like brighter, more hue, etc.  By default it simply returns
     * the value specified by the StyleConstants.Foreground attribute.
     *
     * @param attr the set of attributes
     * @return the color
     */
    public Color getForeground(AttributeSet attr) {
        return StyleConstants.getForeground(attr);
    }

    
Takes a set of attributes and turn it into a background color
specification.  This might be used to specify things
like brighter, more hue, etc.  By default it simply returns
the value specified by the StyleConstants.Background attribute.

Params:
  • attr – the set of attributes
Returns:the color
/**
     * Takes a set of attributes and turn it into a background color
     * specification.  This might be used to specify things
     * like brighter, more hue, etc.  By default it simply returns
     * the value specified by the StyleConstants.Background attribute.
     *
     * @param attr the set of attributes
     * @return the color
     */
    public Color getBackground(AttributeSet attr) {
        return StyleConstants.getBackground(attr);
    }

    
Gets a new font.  This returns a Font from a cache
if a cached font exists.  If not, a Font is added to
the cache.  This is basically a low-level cache for
1.1 font features.

Params:
  • family – the font family (such as "Monospaced")
  • style – the style of the font (such as Font.PLAIN)
  • size – the point size >= 1
Returns:the new font
/**
     * Gets a new font.  This returns a Font from a cache
     * if a cached font exists.  If not, a Font is added to
     * the cache.  This is basically a low-level cache for
     * 1.1 font features.
     *
     * @param family the font family (such as "Monospaced")
     * @param style the style of the font (such as Font.PLAIN)
     * @param size the point size >= 1
     * @return the new font
     */
    public Font getFont(String family, int style, int size) {
        fontSearch.setValue(family, style, size);
        Font f = fontTable.get(fontSearch);
        if (f == null) {
            // haven't seen this one yet.
            Style defaultStyle =
                getStyle(StyleContext.DEFAULT_STYLE);
            if (defaultStyle != null) {
                final String FONT_ATTRIBUTE_KEY = "FONT_ATTRIBUTE_KEY";
                Font defaultFont =
                    (Font) defaultStyle.getAttribute(FONT_ATTRIBUTE_KEY);
                if (defaultFont != null
                      && defaultFont.getFamily().equalsIgnoreCase(family)) {
                    f = defaultFont.deriveFont(style, size);
                }
            }
            if (f == null) {
                f = new Font(family, style, size);
            }
            if (! FontUtilities.fontSupportsDefaultEncoding(f)) {
                f = FontUtilities.getCompositeFontUIResource(f);
            }
            FontKey key = new FontKey(family, style, size);
            fontTable.put(key, f);
        }
        return f;
    }

    
Returns font metrics for a font.

Params:
  • f – the font
Returns:the metrics
/**
     * Returns font metrics for a font.
     *
     * @param f the font
     * @return the metrics
     */
    public FontMetrics getFontMetrics(Font f) {
        // The Toolkit implementations cache, so we just forward
        // to the default toolkit.
        return Toolkit.getDefaultToolkit().getFontMetrics(f);
    }

    // --- AttributeContext methods --------------------

    
Adds an attribute to the given set, and returns
the new representative set.


This method is thread safe, although most Swing methods
are not. Please see
Concurrency
in Swing for more information.

Params:
  • old – the old attribute set
  • name – the non-null attribute name
  • value – the attribute value
See Also:
Returns:the updated attribute set
/**
     * Adds an attribute to the given set, and returns
     * the new representative set.
     * <p>
     * This method is thread safe, although most Swing methods
     * are not. Please see
     * <A HREF="https://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html">Concurrency
     * in Swing</A> for more information.
     *
     * @param old the old attribute set
     * @param name the non-null attribute name
     * @param value the attribute value
     * @return the updated attribute set
     * @see MutableAttributeSet#addAttribute
     */
    public synchronized AttributeSet addAttribute(AttributeSet old, Object name, Object value) {
        if ((old.getAttributeCount() + 1) <= getCompressionThreshold()) {
            // build a search key and find/create an immutable and unique
            // set.
            search.removeAttributes(search);
            search.addAttributes(old);
            search.addAttribute(name, value);
            reclaim(old);
            return getImmutableUniqueSet();
        }
        MutableAttributeSet ma = getMutableAttributeSet(old);
        ma.addAttribute(name, value);
        return ma;
    }

    
Adds a set of attributes to the element.


This method is thread safe, although most Swing methods
are not. Please see
Concurrency
in Swing for more information.

Params:
  • old – the old attribute set
  • attr – the attributes to add
See Also:
Returns:the updated attribute set
/**
     * Adds a set of attributes to the element.
     * <p>
     * This method is thread safe, although most Swing methods
     * are not. Please see
     * <A HREF="https://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html">Concurrency
     * in Swing</A> for more information.
     *
     * @param old the old attribute set
     * @param attr the attributes to add
     * @return the updated attribute set
     * @see MutableAttributeSet#addAttribute
     */
    public synchronized AttributeSet addAttributes(AttributeSet old, AttributeSet attr) {
        if ((old.getAttributeCount() + attr.getAttributeCount()) <= getCompressionThreshold()) {
            // build a search key and find/create an immutable and unique
            // set.
            search.removeAttributes(search);
            search.addAttributes(old);
            search.addAttributes(attr);
            reclaim(old);
            return getImmutableUniqueSet();
        }
        MutableAttributeSet ma = getMutableAttributeSet(old);
        ma.addAttributes(attr);
        return ma;
    }

    
Removes an attribute from the set.


This method is thread safe, although most Swing methods
are not. Please see
Concurrency
in Swing for more information.

Params:
  • old – the old set of attributes
  • name – the non-null attribute name
See Also:
Returns:the updated attribute set
/**
     * Removes an attribute from the set.
     * <p>
     * This method is thread safe, although most Swing methods
     * are not. Please see
     * <A HREF="https://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html">Concurrency
     * in Swing</A> for more information.
     *
     * @param old the old set of attributes
     * @param name the non-null attribute name
     * @return the updated attribute set
     * @see MutableAttributeSet#removeAttribute
     */
    public synchronized AttributeSet removeAttribute(AttributeSet old, Object name) {
        if ((old.getAttributeCount() - 1) <= getCompressionThreshold()) {
            // build a search key and find/create an immutable and unique
            // set.
            search.removeAttributes(search);
            search.addAttributes(old);
            search.removeAttribute(name);
            reclaim(old);
            return getImmutableUniqueSet();
        }
        MutableAttributeSet ma = getMutableAttributeSet(old);
        ma.removeAttribute(name);
        return ma;
    }

    
Removes a set of attributes for the element.


This method is thread safe, although most Swing methods
are not. Please see
Concurrency
in Swing for more information.

Params:
  • old – the old attribute set
  • names – the attribute names
See Also:
Returns:the updated attribute set
/**
     * Removes a set of attributes for the element.
     * <p>
     * This method is thread safe, although most Swing methods
     * are not. Please see
     * <A HREF="https://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html">Concurrency
     * in Swing</A> for more information.
     *
     * @param old the old attribute set
     * @param names the attribute names
     * @return the updated attribute set
     * @see MutableAttributeSet#removeAttributes
     */
    public synchronized AttributeSet removeAttributes(AttributeSet old, Enumeration<?> names) {
        if (old.getAttributeCount() <= getCompressionThreshold()) {
            // build a search key and find/create an immutable and unique
            // set.
            search.removeAttributes(search);
            search.addAttributes(old);
            search.removeAttributes(names);
            reclaim(old);
            return getImmutableUniqueSet();
        }
        MutableAttributeSet ma = getMutableAttributeSet(old);
        ma.removeAttributes(names);
        return ma;
    }

    
Removes a set of attributes for the element.


This method is thread safe, although most Swing methods
are not. Please see
Concurrency
in Swing for more information.

Params:
  • old – the old attribute set
  • attrs – the attributes
See Also:
Returns:the updated attribute set
/**
     * Removes a set of attributes for the element.
     * <p>
     * This method is thread safe, although most Swing methods
     * are not. Please see
     * <A HREF="https://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html">Concurrency
     * in Swing</A> for more information.
     *
     * @param old the old attribute set
     * @param attrs the attributes
     * @return the updated attribute set
     * @see MutableAttributeSet#removeAttributes
     */
    public synchronized AttributeSet removeAttributes(AttributeSet old, AttributeSet attrs) {
        if (old.getAttributeCount() <= getCompressionThreshold()) {
            // build a search key and find/create an immutable and unique
            // set.
            search.removeAttributes(search);
            search.addAttributes(old);
            search.removeAttributes(attrs);
            reclaim(old);
            return getImmutableUniqueSet();
        }
        MutableAttributeSet ma = getMutableAttributeSet(old);
        ma.removeAttributes(attrs);
        return ma;
    }

    
Fetches an empty AttributeSet.

Returns:the set
/**
     * Fetches an empty AttributeSet.
     *
     * @return the set
     */
    public AttributeSet getEmptySet() {
        return SimpleAttributeSet.EMPTY;
    }

    
Returns a set no longer needed by the MutableAttributeSet implementation.
This is useful for operation under 1.1 where there are no weak
references.  This would typically be called by the finalize method
of the MutableAttributeSet implementation.


This method is thread safe, although most Swing methods
are not. Please see
Concurrency
in Swing for more information.

Params:
  • a – the set to reclaim
/**
     * Returns a set no longer needed by the MutableAttributeSet implementation.
     * This is useful for operation under 1.1 where there are no weak
     * references.  This would typically be called by the finalize method
     * of the MutableAttributeSet implementation.
     * <p>
     * This method is thread safe, although most Swing methods
     * are not. Please see
     * <A HREF="https://docs.oracle.com/javase/tutorial/uiswing/concurrency/index.html">Concurrency
     * in Swing</A> for more information.
     *
     * @param a the set to reclaim
     */
    public void reclaim(AttributeSet a) {
        if (SwingUtilities.isEventDispatchThread()) {
            attributesPool.size(); // force WeakHashMap to expunge stale entries
        }
        // if current thread is not event dispatching thread
        // do not bother with expunging stale entries.
    }

    // --- local methods -----------------------------------------------

    
Returns the maximum number of key/value pairs to try and
compress into unique/immutable sets.  Any sets above this
limit will use hashtables and be a MutableAttributeSet.

Returns:the threshold
/**
     * Returns the maximum number of key/value pairs to try and
     * compress into unique/immutable sets.  Any sets above this
     * limit will use hashtables and be a MutableAttributeSet.
     *
     * @return the threshold
     */
    protected int getCompressionThreshold() {
        return THRESHOLD;
    }

    
Create a compact set of attributes that might be shared.
This is a hook for subclasses that want to alter the
behavior of SmallAttributeSet.  This can be reimplemented
to return an AttributeSet that provides some sort of
attribute conversion.

Params:
  • a – The set of attributes to be represented in the
 the compact form.
/**
     * Create a compact set of attributes that might be shared.
     * This is a hook for subclasses that want to alter the
     * behavior of SmallAttributeSet.  This can be reimplemented
     * to return an AttributeSet that provides some sort of
     * attribute conversion.
     *
     * @param a The set of attributes to be represented in the
     *  the compact form.
     */
    protected SmallAttributeSet createSmallAttributeSet(AttributeSet a) {
        return new SmallAttributeSet(a);
    }

    
Create a large set of attributes that should trade off
space for time.  This set will not be shared.  This is
a hook for subclasses that want to alter the behavior
of the larger attribute storage format (which is
SimpleAttributeSet by default).   This can be reimplemented
to return a MutableAttributeSet that provides some sort of
attribute conversion.

Params:
  • a – The set of attributes to be represented in the
 the larger form.
/**
     * Create a large set of attributes that should trade off
     * space for time.  This set will not be shared.  This is
     * a hook for subclasses that want to alter the behavior
     * of the larger attribute storage format (which is
     * SimpleAttributeSet by default).   This can be reimplemented
     * to return a MutableAttributeSet that provides some sort of
     * attribute conversion.
     *
     * @param a The set of attributes to be represented in the
     *  the larger form.
     */
    protected MutableAttributeSet createLargeAttributeSet(AttributeSet a) {
        return new SimpleAttributeSet(a);
    }

    
Clean the unused immutable sets out of the hashtable.

/**
     * Clean the unused immutable sets out of the hashtable.
     */
    synchronized void removeUnusedSets() {
        attributesPool.size(); // force WeakHashMap to expunge stale entries
    }

    
Search for an existing attribute set using the current search
parameters.  If a matching set is found, return it.  If a match
is not found, we create a new set and add it to the pool.

/**
     * Search for an existing attribute set using the current search
     * parameters.  If a matching set is found, return it.  If a match
     * is not found, we create a new set and add it to the pool.
     */
    AttributeSet getImmutableUniqueSet() {
        // PENDING(prinz) should consider finding a alternative to
        // generating extra garbage on search key.
        SmallAttributeSet key = createSmallAttributeSet(search);
        WeakReference<SmallAttributeSet> reference = attributesPool.get(key);
        SmallAttributeSet a;
        if (reference == null || (a = reference.get()) == null) {
            a = key;
            attributesPool.put(a, new WeakReference<SmallAttributeSet>(a));
        }
        return a;
    }

    
Creates a mutable attribute set to hand out because the current
needs are too big to try and use a shared version.

/**
     * Creates a mutable attribute set to hand out because the current
     * needs are too big to try and use a shared version.
     */
    MutableAttributeSet getMutableAttributeSet(AttributeSet a) {
        if (a instanceof MutableAttributeSet &&
            a != SimpleAttributeSet.EMPTY) {
            return (MutableAttributeSet) a;
        }
        return createLargeAttributeSet(a);
    }

    
Converts a StyleContext to a String.

Returns:the string
/**
     * Converts a StyleContext to a String.
     *
     * @return the string
     */
    public String toString() {
        removeUnusedSets();
        String s = "";
        for (SmallAttributeSet set : attributesPool.keySet()) {
            s = s + set + "\n";
        }
        return s;
    }

    // --- serialization ---------------------------------------------

    
Context-specific handling of writing out attributes

/**
     * Context-specific handling of writing out attributes
     */
    public void writeAttributes(ObjectOutputStream out,
                                  AttributeSet a) throws IOException {
        writeAttributeSet(out, a);
    }

    
Context-specific handling of reading in attributes

/**
     * Context-specific handling of reading in attributes
     */
    public void readAttributes(ObjectInputStream in,
                               MutableAttributeSet a) throws ClassNotFoundException, IOException {
        readAttributeSet(in, a);
    }

    
Writes a set of attributes to the given object stream
for the purpose of serialization.  This will take
special care to deal with static attribute keys that
have been registered wit the
registerStaticAttributeKey method.
Any attribute key not registered as a static key
will be serialized directly.  All values are expected
to be serializable.

Params:
  • out – the output stream
  • a – the attribute set
Throws:
/**
     * Writes a set of attributes to the given object stream
     * for the purpose of serialization.  This will take
     * special care to deal with static attribute keys that
     * have been registered wit the
     * <code>registerStaticAttributeKey</code> method.
     * Any attribute key not registered as a static key
     * will be serialized directly.  All values are expected
     * to be serializable.
     *
     * @param out the output stream
     * @param a the attribute set
     * @exception IOException on any I/O error
     */
    public static void writeAttributeSet(ObjectOutputStream out,
                                         AttributeSet a) throws IOException {
        int n = a.getAttributeCount();
        out.writeInt(n);
        Enumeration keys = a.getAttributeNames();
        while (keys.hasMoreElements()) {
            Object key = keys.nextElement();
            if (key instanceof Serializable) {
                out.writeObject(key);
            } else {
                Object ioFmt = freezeKeyMap.get(key);
                if (ioFmt == null) {
                    throw new NotSerializableException(key.getClass().
                                 getName() + " is not serializable as a key in an AttributeSet");
                }
                out.writeObject(ioFmt);
            }
            Object value = a.getAttribute(key);
            Object ioFmt = freezeKeyMap.get(value);
            if (value instanceof Serializable) {
                out.writeObject((ioFmt != null) ? ioFmt : value);
            } else {
                if (ioFmt == null) {
                    throw new NotSerializableException(value.getClass().
                                 getName() + " is not serializable as a value in an AttributeSet");
                }
                out.writeObject(ioFmt);
            }
        }
    }

    
Reads a set of attributes from the given object input
stream that have been previously written out with
writeAttributeSet.  This will try to restore
keys that were static objects to the static objects in
the current virtual machine considering only those keys
that have been registered with the
registerStaticAttributeKey method.
The attributes retrieved from the stream will be placed
into the given mutable set.

Params:
  • in – the object stream to read the attribute data from.
  • a –  the attribute set to place the attribute
  definitions in.
Throws:
/**
     * Reads a set of attributes from the given object input
     * stream that have been previously written out with
     * <code>writeAttributeSet</code>.  This will try to restore
     * keys that were static objects to the static objects in
     * the current virtual machine considering only those keys
     * that have been registered with the
     * <code>registerStaticAttributeKey</code> method.
     * The attributes retrieved from the stream will be placed
     * into the given mutable set.
     *
     * @param in the object stream to read the attribute data from.
     * @param a  the attribute set to place the attribute
     *   definitions in.
     * @exception ClassNotFoundException passed upward if encountered
     *  when reading the object stream.
     * @exception IOException passed upward if encountered when
     *  reading the object stream.
     */
    public static void readAttributeSet(ObjectInputStream in,
        MutableAttributeSet a) throws ClassNotFoundException, IOException {

        int n = in.readInt();
        for (int i = 0; i < n; i++) {
            Object key = in.readObject();
            Object value = in.readObject();
            if (thawKeyMap != null) {
                Object staticKey = thawKeyMap.get(key);
                if (staticKey != null) {
                    key = staticKey;
                }
                Object staticValue = thawKeyMap.get(value);
                if (staticValue != null) {
                    value = staticValue;
                }
            }
            a.addAttribute(key, value);
        }
    }

    
Registers an object as a static object that is being
used as a key in attribute sets.  This allows the key
to be treated specially for serialization.


For operation under a 1.1 virtual machine, this
uses the value returned by toString
concatenated to the classname.  The value returned
by toString should not have the class reference
in it (ie it should be reimplemented from the
definition in Object) in order to be the same when
recomputed later.

Params:
  • key – the non-null object key
/**
     * Registers an object as a static object that is being
     * used as a key in attribute sets.  This allows the key
     * to be treated specially for serialization.
     * <p>
     * For operation under a 1.1 virtual machine, this
     * uses the value returned by <code>toString</code>
     * concatenated to the classname.  The value returned
     * by toString should not have the class reference
     * in it (ie it should be reimplemented from the
     * definition in Object) in order to be the same when
     * recomputed later.
     *
     * @param key the non-null object key
     */
    public static void registerStaticAttributeKey(Object key) {
        String ioFmt = key.getClass().getName() + "." + key.toString();
        if (freezeKeyMap == null) {
            freezeKeyMap = new Hashtable<Object, String>();
            thawKeyMap = new Hashtable<String, Object>();
        }
        freezeKeyMap.put(key, ioFmt);
        thawKeyMap.put(ioFmt, key);
    }

    
Returns the object previously registered with
registerStaticAttributeKey.

/**
     * Returns the object previously registered with
     * <code>registerStaticAttributeKey</code>.
     */
    public static Object getStaticAttribute(Object key) {
        if (thawKeyMap == null || key == null) {
            return null;
        }
        return thawKeyMap.get(key);
    }

    
Returns the String that key will be registered with

See Also:
/**
     * Returns the String that <code>key</code> will be registered with
     * @see #getStaticAttribute
     * @see #registerStaticAttributeKey
     */
    public static Object getStaticAttributeKey(Object key) {
        return key.getClass().getName() + "." + key.toString();
    }

    private void writeObject(java.io.ObjectOutputStream s)
        throws IOException
    {
        // clean out unused sets before saving
        removeUnusedSets();

        s.defaultWriteObject();
    }

    private void readObject(ObjectInputStream s)
      throws ClassNotFoundException, IOException
    {
        fontSearch = new FontKey(null, 0, 0);
        fontTable = new Hashtable<FontKey, Font>();
        search = new SimpleAttributeSet();
        attributesPool = Collections.
                synchronizedMap(new WeakHashMap<SmallAttributeSet, WeakReference<SmallAttributeSet>>());
        s.defaultReadObject();
    }

    // --- variables ---------------------------------------------------

    
The name given to the default logical style attached
to paragraphs.

/**
     * The name given to the default logical style attached
     * to paragraphs.
     */
    public static final String DEFAULT_STYLE = "default";

    private static Hashtable<Object, String> freezeKeyMap;
    private static Hashtable<String, Object> thawKeyMap;

    private Style styles;
    private transient FontKey fontSearch = new FontKey(null, 0, 0);
    private transient Hashtable<FontKey, Font> fontTable = new Hashtable<FontKey, Font>();

    private transient Map<SmallAttributeSet, WeakReference<SmallAttributeSet>> attributesPool = Collections.
            synchronizedMap(new WeakHashMap<SmallAttributeSet, WeakReference<SmallAttributeSet>>());
    private transient MutableAttributeSet search = new SimpleAttributeSet();

    
Number of immutable sets that are not currently
being used.  This helps indicate when the sets need
to be cleaned out of the hashtable they are stored
in.

/**
     * Number of immutable sets that are not currently
     * being used.  This helps indicate when the sets need
     * to be cleaned out of the hashtable they are stored
     * in.
     */
    private int unusedSets;

    
The threshold for no longer sharing the set of attributes
in an immutable table.

/**
     * The threshold for no longer sharing the set of attributes
     * in an immutable table.
     */
    static final int THRESHOLD = 9;

    
This class holds a small number of attributes in an array.
The storage format is key, value, key, value, etc.  The size
of the set is the length of the array divided by two.  By
default, this is the class that will be used to store attributes
when held in the compact sharable form.

/**
     * This class holds a small number of attributes in an array.
     * The storage format is key, value, key, value, etc.  The size
     * of the set is the length of the array divided by two.  By
     * default, this is the class that will be used to store attributes
     * when held in the compact sharable form.
     */
    public class SmallAttributeSet implements AttributeSet {

        public SmallAttributeSet(Object[] attributes) {
            this.attributes = attributes;
            updateResolveParent();
        }

        public SmallAttributeSet(AttributeSet attrs) {
            int n = attrs.getAttributeCount();
            Object[] tbl = new Object[2 * n];
            Enumeration names = attrs.getAttributeNames();
            int i = 0;
            while (names.hasMoreElements()) {
                tbl[i] = names.nextElement();
                tbl[i+1] = attrs.getAttribute(tbl[i]);
                i += 2;
            }
            attributes = tbl;
            updateResolveParent();
        }

        private void updateResolveParent() {
            resolveParent = null;
            Object[] tbl = attributes;
            for (int i = 0; i < tbl.length; i += 2) {
                if (tbl[i] == StyleConstants.ResolveAttribute) {
                    resolveParent = (AttributeSet)tbl[i + 1];
                    break;
                }
            }
        }

        Object getLocalAttribute(Object nm) {
            if (nm == StyleConstants.ResolveAttribute) {
                return resolveParent;
            }
            Object[] tbl = attributes;
            for (int i = 0; i < tbl.length; i += 2) {
                if (nm.equals(tbl[i])) {
                    return tbl[i+1];
                }
            }
            return null;
        }

        // --- Object methods -------------------------

        
Returns a string showing the key/value pairs

/**
         * Returns a string showing the key/value pairs
         */
        public String toString() {
            String s = "{";
            Object[] tbl = attributes;
            for (int i = 0; i < tbl.length; i += 2) {
                if (tbl[i+1] instanceof AttributeSet) {
                    // don't recurse
                    s = s + tbl[i] + "=" + "AttributeSet" + ",";
                } else {
                    s = s + tbl[i] + "=" + tbl[i+1] + ",";
                }
            }
            s = s + "}";
            return s;
        }

        
Returns a hashcode for this set of attributes.

Returns:    a hashcode value for this set of attributes.
/**
         * Returns a hashcode for this set of attributes.
         * @return     a hashcode value for this set of attributes.
         */
        public int hashCode() {
            int code = 0;
            Object[] tbl = attributes;
            for (int i = 1; i < tbl.length; i += 2) {
                code ^= tbl[i].hashCode();
            }
            return code;
        }

        
Compares this object to the specified object.
The result is true if the object is an equivalent
set of attributes.

Params:
  • obj –   the object to compare with.
Returns:   true if the objects are equal;
           false otherwise.
/**
         * Compares this object to the specified object.
         * The result is <code>true</code> if the object is an equivalent
         * set of attributes.
         * @param     obj   the object to compare with.
         * @return    <code>true</code> if the objects are equal;
         *            <code>false</code> otherwise.
         */
        public boolean equals(Object obj) {
            if (obj instanceof AttributeSet) {
                AttributeSet attrs = (AttributeSet) obj;
                return ((getAttributeCount() == attrs.getAttributeCount()) &&
                        containsAttributes(attrs));
            }
            return false;
        }

        
Clones a set of attributes.  Since the set is immutable, a
clone is basically the same set.

Returns:the set of attributes
/**
         * Clones a set of attributes.  Since the set is immutable, a
         * clone is basically the same set.
         *
         * @return the set of attributes
         */
        public Object clone() {
            return this;
        }

        //  --- AttributeSet methods ----------------------------

        
Gets the number of attributes that are defined.

See Also:
Returns:the number of attributes
/**
         * Gets the number of attributes that are defined.
         *
         * @return the number of attributes
         * @see AttributeSet#getAttributeCount
         */
        public int getAttributeCount() {
            return attributes.length / 2;
        }

        
Checks whether a given attribute is defined.

Params:
  • key – the attribute key
See Also:
Returns:true if the attribute is defined
/**
         * Checks whether a given attribute is defined.
         *
         * @param key the attribute key
         * @return true if the attribute is defined
         * @see AttributeSet#isDefined
         */
        public boolean isDefined(Object key) {
            Object[] a = attributes;
            int n = a.length;
            for (int i = 0; i < n; i += 2) {
                if (key.equals(a[i])) {
                    return true;
                }
            }
            return false;
        }

        
Checks whether two attribute sets are equal.

Params:
  • attr – the attribute set to check against
See Also:
Returns:true if the same
/**
         * Checks whether two attribute sets are equal.
         *
         * @param attr the attribute set to check against
         * @return true if the same
         * @see AttributeSet#isEqual
         */
        public boolean isEqual(AttributeSet attr) {
            if (attr instanceof SmallAttributeSet) {
                return attr == this;
            }
            return ((getAttributeCount() == attr.getAttributeCount()) &&
                    containsAttributes(attr));
        }

        
Copies a set of attributes.

See Also:
Returns:the copy
/**
         * Copies a set of attributes.
         *
         * @return the copy
         * @see AttributeSet#copyAttributes
         */
        public AttributeSet copyAttributes() {
            return this;
        }

        
Gets the value of an attribute.

Params:
  • key – the attribute name
See Also:
Returns:the attribute value
/**
         * Gets the value of an attribute.
         *
         * @param key the attribute name
         * @return the attribute value
         * @see AttributeSet#getAttribute
         */
        public Object getAttribute(Object key) {
            Object value = getLocalAttribute(key);
            if (value == null) {
                AttributeSet parent = getResolveParent();
                if (parent != null)
                    value = parent.getAttribute(key);
            }
            return value;
        }

        
Gets the names of all attributes.

See Also:
Returns:the attribute names
/**
         * Gets the names of all attributes.
         *
         * @return the attribute names
         * @see AttributeSet#getAttributeNames
         */
        public Enumeration<?> getAttributeNames() {
            return new KeyEnumeration(attributes);
        }

        
Checks whether a given attribute name/value is defined.

Params:
  • name – the attribute name
  • value – the attribute value
See Also:
Returns:true if the name/value is defined
/**
         * Checks whether a given attribute name/value is defined.
         *
         * @param name the attribute name
         * @param value the attribute value
         * @return true if the name/value is defined
         * @see AttributeSet#containsAttribute
         */
        public boolean containsAttribute(Object name, Object value) {
            return value.equals(getAttribute(name));
        }

        
Checks whether the attribute set contains all of
the given attributes.

Params:
  • attrs – the attributes to check
See Also:
Returns:true if the element contains all the attributes
/**
         * Checks whether the attribute set contains all of
         * the given attributes.
         *
         * @param attrs the attributes to check
         * @return true if the element contains all the attributes
         * @see AttributeSet#containsAttributes
         */
        public boolean containsAttributes(AttributeSet attrs) {
            boolean result = true;

            Enumeration names = attrs.getAttributeNames();
            while (result && names.hasMoreElements()) {
                Object name = names.nextElement();
                result = attrs.getAttribute(name).equals(getAttribute(name));
            }

            return result;
        }

        
If not overriden, the resolving parent defaults to
the parent element.

See Also:
Returns:the attributes from the parent
/**
         * If not overriden, the resolving parent defaults to
         * the parent element.
         *
         * @return the attributes from the parent
         * @see AttributeSet#getResolveParent
         */
        public AttributeSet getResolveParent() {
            return resolveParent;
        }

        // --- variables -----------------------------------------

        Object[] attributes;
        // This is also stored in attributes
        AttributeSet resolveParent;
    }

    
An enumeration of the keys in a SmallAttributeSet.

/**
     * An enumeration of the keys in a SmallAttributeSet.
     */
    class KeyEnumeration implements Enumeration<Object> {

        KeyEnumeration(Object[] attr) {
            this.attr = attr;
            i = 0;
        }

        
Tests if this enumeration contains more elements.

Returns: true if this enumeration contains more elements;
         false otherwise.
Since:  JDK1.0
/**
         * Tests if this enumeration contains more elements.
         *
         * @return  <code>true</code> if this enumeration contains more elements;
         *          <code>false</code> otherwise.
         * @since   JDK1.0
         */
        public boolean hasMoreElements() {
            return i < attr.length;
        }

        
Returns the next element of this enumeration.

Throws:
Returns:    the next element of this enumeration.
Since:     JDK1.0
/**
         * Returns the next element of this enumeration.
         *
         * @return     the next element of this enumeration.
         * @exception  NoSuchElementException  if no more elements exist.
         * @since      JDK1.0
         */
        public Object nextElement() {
            if (i < attr.length) {
                Object o = attr[i];
                i += 2;
                return o;
            }
            throw new NoSuchElementException();
        }

        Object[] attr;
        int i;
    }

    
Sorts the key strings so that they can be very quickly compared
in the attribute set searches.

/**
     * Sorts the key strings so that they can be very quickly compared
     * in the attribute set searches.
     */
    class KeyBuilder {

        public void initialize(AttributeSet a) {
            if (a instanceof SmallAttributeSet) {
                initialize(((SmallAttributeSet)a).attributes);
            } else {
                keys.removeAllElements();
                data.removeAllElements();
                Enumeration names = a.getAttributeNames();
                while (names.hasMoreElements()) {
                    Object name = names.nextElement();
                    addAttribute(name, a.getAttribute(name));
                }
            }
        }

        
Initialize with a set of already sorted
keys (data from an existing SmallAttributeSet).

/**
         * Initialize with a set of already sorted
         * keys (data from an existing SmallAttributeSet).
         */
        private void initialize(Object[] sorted) {
            keys.removeAllElements();
            data.removeAllElements();
            int n = sorted.length;
            for (int i = 0; i < n; i += 2) {
                keys.addElement(sorted[i]);
                data.addElement(sorted[i+1]);
            }
        }

        
Creates a table of sorted key/value entries
suitable for creation of an instance of
SmallAttributeSet.

/**
         * Creates a table of sorted key/value entries
         * suitable for creation of an instance of
         * SmallAttributeSet.
         */
        public Object[] createTable() {
            int n = keys.size();
            Object[] tbl = new Object[2 * n];
            for (int i = 0; i < n; i ++) {
                int offs = 2 * i;
                tbl[offs] = keys.elementAt(i);
                tbl[offs + 1] = data.elementAt(i);
            }
            return tbl;
        }

        
The number of key/value pairs contained
in the current key being forged.

/**
         * The number of key/value pairs contained
         * in the current key being forged.
         */
        int getCount() {
            return keys.size();
        }

        
Adds a key/value to the set.

/**
         * Adds a key/value to the set.
         */
        public void addAttribute(Object key, Object value) {
            keys.addElement(key);
            data.addElement(value);
        }

        
Adds a set of key/value pairs to the set.

/**
         * Adds a set of key/value pairs to the set.
         */
        public void addAttributes(AttributeSet attr) {
            if (attr instanceof SmallAttributeSet) {
                // avoid searching the keys, they are already interned.
                Object[] tbl = ((SmallAttributeSet)attr).attributes;
                int n = tbl.length;
                for (int i = 0; i < n; i += 2) {
                    addAttribute(tbl[i], tbl[i+1]);
                }
            } else {
                Enumeration names = attr.getAttributeNames();
                while (names.hasMoreElements()) {
                    Object name = names.nextElement();
                    addAttribute(name, attr.getAttribute(name));
                }
            }
        }

        
Removes the given name from the set.

/**
         * Removes the given name from the set.
         */
        public void removeAttribute(Object key) {
            int n = keys.size();
            for (int i = 0; i < n; i++) {
                if (keys.elementAt(i).equals(key)) {
                    keys.removeElementAt(i);
                    data.removeElementAt(i);
                    return;
                }
            }
        }

        
Removes the set of keys from the set.

/**
         * Removes the set of keys from the set.
         */
        public void removeAttributes(Enumeration names) {
            while (names.hasMoreElements()) {
                Object name = names.nextElement();
                removeAttribute(name);
            }
        }

        
Removes the set of matching attributes from the set.

/**
         * Removes the set of matching attributes from the set.
         */
        public void removeAttributes(AttributeSet attr) {
            Enumeration names = attr.getAttributeNames();
            while (names.hasMoreElements()) {
                Object name = names.nextElement();
                Object value = attr.getAttribute(name);
                removeSearchAttribute(name, value);
            }
        }

        private void removeSearchAttribute(Object ikey, Object value) {
            int n = keys.size();
            for (int i = 0; i < n; i++) {
                if (keys.elementAt(i).equals(ikey)) {
                    if (data.elementAt(i).equals(value)) {
                        keys.removeElementAt(i);
                        data.removeElementAt(i);
                    }
                    return;
                }
            }
        }

        private Vector<Object> keys = new Vector<Object>();
        private Vector<Object> data = new Vector<Object>();
    }

    
key for a font table

/**
     * key for a font table
     */
    static class FontKey {

        private String family;
        private int style;
        private int size;

        
Constructs a font key.

/**
         * Constructs a font key.
         */
        public FontKey(String family, int style, int size) {
            setValue(family, style, size);
        }

        public void setValue(String family, int style, int size) {
            this.family = (family != null) ? family.intern() : null;
            this.style = style;
            this.size = size;
        }

        
Returns a hashcode for this font.

Returns:    a hashcode value for this font.
/**
         * Returns a hashcode for this font.
         * @return     a hashcode value for this font.
         */
        public int hashCode() {
            int fhash = (family != null) ? family.hashCode() : 0;
            return fhash ^ style ^ size;
        }

        
Compares this object to the specified object.
The result is true if and only if the argument is not
null and is a Font object with the same
name, style, and point size as this font.

Params:
  • obj –   the object to compare this font with.
Returns:   true if the objects are equal;
           false otherwise.
/**
         * Compares this object to the specified object.
         * The result is <code>true</code> if and only if the argument is not
         * <code>null</code> and is a <code>Font</code> object with the same
         * name, style, and point size as this font.
         * @param     obj   the object to compare this font with.
         * @return    <code>true</code> if the objects are equal;
         *            <code>false</code> otherwise.
         */
        public boolean equals(Object obj) {
            if (obj instanceof FontKey) {
                FontKey font = (FontKey)obj;
                return (size == font.size) && (style == font.style) && (family == font.family);
            }
            return false;
        }

    }

    
A collection of attributes, typically used to represent
character and paragraph styles.  This is an implementation
of MutableAttributeSet that can be observed if desired.
These styles will take advantage of immutability while
the sets are small enough, and may be substantially more
efficient than something like SimpleAttributeSet.


Warning:
Serialized objects of this class will not be compatible with
future Swing releases. The current serialization support is
appropriate for short term storage or RMI between applications running
the same version of Swing.  As of 1.4, support for long term storage
of all JavaBeansTM
has been added to the java.beans package. Please see XMLEncoder. 
/**
     * A collection of attributes, typically used to represent
     * character and paragraph styles.  This is an implementation
     * of MutableAttributeSet that can be observed if desired.
     * These styles will take advantage of immutability while
     * the sets are small enough, and may be substantially more
     * efficient than something like SimpleAttributeSet.
     * <p>
     * <strong>Warning:</strong>
     * Serialized objects of this class will not be compatible with
     * future Swing releases. The current serialization support is
     * appropriate for short term storage or RMI between applications running
     * the same version of Swing.  As of 1.4, support for long term storage
     * of all JavaBeans<sup><font size="-2">TM</font></sup>
     * has been added to the <code>java.beans</code> package.
     * Please see {@link java.beans.XMLEncoder}.
     */
    public class NamedStyle implements Style, Serializable {

        
Creates a new named style.

Params:
  • name – the style name, null for unnamed
  • parent – the parent style, null if none
Since:1.4
/**
         * Creates a new named style.
         *
         * @param name the style name, null for unnamed
         * @param parent the parent style, null if none
         * @since 1.4
         */
        public NamedStyle(String name, Style parent) {
            attributes = getEmptySet();
            if (name != null) {
                setName(name);
            }
            if (parent != null) {
                setResolveParent(parent);
            }
        }

        
Creates a new named style.

Params:
  • parent – the parent style, null if none
Since:1.4
/**
         * Creates a new named style.
         *
         * @param parent the parent style, null if none
         * @since 1.4
         */
        public NamedStyle(Style parent) {
            this(null, parent);
        }

        
Creates a new named style, with a null name and parent.

/**
         * Creates a new named style, with a null name and parent.
         */
        public NamedStyle() {
            attributes = getEmptySet();
        }

        
Converts the style to a string.

Returns:the string
/**
         * Converts the style to a string.
         *
         * @return the string
         */
        public String toString() {
            return "NamedStyle:" + getName() + " " + attributes;
        }

        
Fetches the name of the style.   A style is not required to be named,
so null is returned if there is no name associated with the style.

Returns:the name
/**
         * Fetches the name of the style.   A style is not required to be named,
         * so null is returned if there is no name associated with the style.
         *
         * @return the name
         */
        public String getName() {
            if (isDefined(StyleConstants.NameAttribute)) {
                return getAttribute(StyleConstants.NameAttribute).toString();
            }
            return null;
        }

        
Changes the name of the style.  Does nothing with a null name.

Params:
  • name – the new name
/**
         * Changes the name of the style.  Does nothing with a null name.
         *
         * @param name the new name
         */
        public void setName(String name) {
            if (name != null) {
                this.addAttribute(StyleConstants.NameAttribute, name);
            }
        }

        
Adds a change listener.

Params:
  • l – the change listener
/**
         * Adds a change listener.
         *
         * @param l the change listener
         */
        public void addChangeListener(ChangeListener l) {
            listenerList.add(ChangeListener.class, l);
        }

        
Removes a change listener.

Params:
  • l – the change listener
/**
         * Removes a change listener.
         *
         * @param l the change listener
         */
        public void removeChangeListener(ChangeListener l) {
            listenerList.remove(ChangeListener.class, l);
        }


        
Returns an array of all the ChangeListeners added
to this NamedStyle with addChangeListener().

Returns:all of the ChangeListeners added or an empty
        array if no listeners have been added
Since:1.4
/**
         * Returns an array of all the <code>ChangeListener</code>s added
         * to this NamedStyle with addChangeListener().
         *
         * @return all of the <code>ChangeListener</code>s added or an empty
         *         array if no listeners have been added
         * @since 1.4
         */
        public ChangeListener[] getChangeListeners() {
            return listenerList.getListeners(ChangeListener.class);
        }


        
Notifies all listeners that have registered interest for
notification on this event type.  The event instance
is lazily created using the parameters passed into
the fire method.

See Also:
  • EventListenerList
/**
         * Notifies all listeners that have registered interest for
         * notification on this event type.  The event instance
         * is lazily created using the parameters passed into
         * the fire method.
         *
         * @see EventListenerList
         */
        protected void fireStateChanged() {
            // Guaranteed to return a non-null array
            Object[] listeners = listenerList.getListenerList();
            // Process the listeners last to first, notifying
            // those that are interested in this event
            for (int i = listeners.length-2; i>=0; i-=2) {
                if (listeners[i]==ChangeListener.class) {
                    // Lazily create the event:
                    if (changeEvent == null)
                        changeEvent = new ChangeEvent(this);
                    ((ChangeListener)listeners[i+1]).stateChanged(changeEvent);
                }
            }
        }

        
Return an array of all the listeners of the given type that
were added to this model.

Returns:all of the objects receiving listenerType notifications
         from this model
Since:1.3
/**
         * Return an array of all the listeners of the given type that
         * were added to this model.
         *
         * @return all of the objects receiving <em>listenerType</em> notifications
         *          from this model
         *
         * @since 1.3
         */
        public <T extends EventListener> T[] getListeners(Class<T> listenerType) {
            return listenerList.getListeners(listenerType);
        }

        // --- AttributeSet ----------------------------
        // delegated to the immutable field "attributes"

        
Gets the number of attributes that are defined.

See Also:
Returns:the number of attributes >= 0
/**
         * Gets the number of attributes that are defined.
         *
         * @return the number of attributes >= 0
         * @see AttributeSet#getAttributeCount
         */
        public int getAttributeCount() {
            return attributes.getAttributeCount();
        }

        
Checks whether a given attribute is defined.

Params:
  • attrName – the non-null attribute name
See Also:
Returns:true if the attribute is defined
/**
         * Checks whether a given attribute is defined.
         *
         * @param attrName the non-null attribute name
         * @return true if the attribute is defined
         * @see AttributeSet#isDefined
         */
        public boolean isDefined(Object attrName) {
            return attributes.isDefined(attrName);
        }

        
Checks whether two attribute sets are equal.

Params:
  • attr – the attribute set to check against
See Also:
Returns:true if the same
/**
         * Checks whether two attribute sets are equal.
         *
         * @param attr the attribute set to check against
         * @return true if the same
         * @see AttributeSet#isEqual
         */
        public boolean isEqual(AttributeSet attr) {
            return attributes.isEqual(attr);
        }

        
Copies a set of attributes.

See Also:
Returns:the copy
/**
         * Copies a set of attributes.
         *
         * @return the copy
         * @see AttributeSet#copyAttributes
         */
        public AttributeSet copyAttributes() {
            NamedStyle a = new NamedStyle();
            a.attributes = attributes.copyAttributes();
            return a;
        }

        
Gets the value of an attribute.

Params:
  • attrName – the non-null attribute name
See Also:
Returns:the attribute value
/**
         * Gets the value of an attribute.
         *
         * @param attrName the non-null attribute name
         * @return the attribute value
         * @see AttributeSet#getAttribute
         */
        public Object getAttribute(Object attrName) {
            return attributes.getAttribute(attrName);
        }

        
Gets the names of all attributes.

See Also:
Returns:the attribute names as an enumeration
/**
         * Gets the names of all attributes.
         *
         * @return the attribute names as an enumeration
         * @see AttributeSet#getAttributeNames
         */
        public Enumeration<?> getAttributeNames() {
            return attributes.getAttributeNames();
        }

        
Checks whether a given attribute name/value is defined.

Params:
  • name – the non-null attribute name
  • value – the attribute value
See Also:
Returns:true if the name/value is defined
/**
         * Checks whether a given attribute name/value is defined.
         *
         * @param name the non-null attribute name
         * @param value the attribute value
         * @return true if the name/value is defined
         * @see AttributeSet#containsAttribute
         */
        public boolean containsAttribute(Object name, Object value) {
            return attributes.containsAttribute(name, value);
        }


        
Checks whether the element contains all the attributes.

Params:
  • attrs – the attributes to check
See Also:
Returns:true if the element contains all the attributes
/**
         * Checks whether the element contains all the attributes.
         *
         * @param attrs the attributes to check
         * @return true if the element contains all the attributes
         * @see AttributeSet#containsAttributes
         */
        public boolean containsAttributes(AttributeSet attrs) {
            return attributes.containsAttributes(attrs);
        }

        
Gets attributes from the parent.
If not overriden, the resolving parent defaults to
the parent element.

See Also:
Returns:the attributes from the parent
/**
         * Gets attributes from the parent.
         * If not overriden, the resolving parent defaults to
         * the parent element.
         *
         * @return the attributes from the parent
         * @see AttributeSet#getResolveParent
         */
        public AttributeSet getResolveParent() {
            return attributes.getResolveParent();
        }

        // --- MutableAttributeSet ----------------------------------
        // should fetch a new immutable record for the field
        // "attributes".

        
Adds an attribute.

Params:
  • name – the non-null attribute name
  • value – the attribute value
See Also:
/**
         * Adds an attribute.
         *
         * @param name the non-null attribute name
         * @param value the attribute value
         * @see MutableAttributeSet#addAttribute
         */
        public void addAttribute(Object name, Object value) {
            StyleContext context = StyleContext.this;
            attributes = context.addAttribute(attributes, name, value);
            fireStateChanged();
        }

        
Adds a set of attributes to the element.

Params:
  • attr – the attributes to add
See Also:
/**
         * Adds a set of attributes to the element.
         *
         * @param attr the attributes to add
         * @see MutableAttributeSet#addAttribute
         */
        public void addAttributes(AttributeSet attr) {
            StyleContext context = StyleContext.this;
            attributes = context.addAttributes(attributes, attr);
            fireStateChanged();
        }

        
Removes an attribute from the set.

Params:
  • name – the non-null attribute name
See Also:
/**
         * Removes an attribute from the set.
         *
         * @param name the non-null attribute name
         * @see MutableAttributeSet#removeAttribute
         */
        public void removeAttribute(Object name) {
            StyleContext context = StyleContext.this;
            attributes = context.removeAttribute(attributes, name);
            fireStateChanged();
        }

        
Removes a set of attributes for the element.

Params:
  • names – the attribute names
See Also:
/**
         * Removes a set of attributes for the element.
         *
         * @param names the attribute names
         * @see MutableAttributeSet#removeAttributes
         */
        public void removeAttributes(Enumeration<?> names) {
            StyleContext context = StyleContext.this;
            attributes = context.removeAttributes(attributes, names);
            fireStateChanged();
        }

        
Removes a set of attributes for the element.

Params:
  • attrs – the attributes
See Also:
/**
         * Removes a set of attributes for the element.
         *
         * @param attrs the attributes
         * @see MutableAttributeSet#removeAttributes
         */
        public void removeAttributes(AttributeSet attrs) {
            StyleContext context = StyleContext.this;
            if (attrs == this) {
                attributes = context.getEmptySet();
            } else {
                attributes = context.removeAttributes(attributes, attrs);
            }
            fireStateChanged();
        }

        
Sets the resolving parent.

Params:
  • parent – the parent, null if none
See Also:
/**
         * Sets the resolving parent.
         *
         * @param parent the parent, null if none
         * @see MutableAttributeSet#setResolveParent
         */
        public void setResolveParent(AttributeSet parent) {
            if (parent != null) {
                addAttribute(StyleConstants.ResolveAttribute, parent);
            } else {
                removeAttribute(StyleConstants.ResolveAttribute);
            }
        }

        // --- serialization ---------------------------------------------

        private void writeObject(ObjectOutputStream s) throws IOException {
            s.defaultWriteObject();
            writeAttributeSet(s, attributes);
        }

        private void readObject(ObjectInputStream s)
            throws ClassNotFoundException, IOException
        {
            s.defaultReadObject();
            attributes = SimpleAttributeSet.EMPTY;
            readAttributeSet(s, this);
        }

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

        
The change listeners for the model.

/**
         * The change listeners for the model.
         */
        protected EventListenerList listenerList = new EventListenerList();

        
Only one ChangeEvent is needed per model instance since the
event's only (read-only) state is the source property.  The source
of events generated here is always "this".

/**
         * Only one ChangeEvent is needed per model instance since the
         * event's only (read-only) state is the source property.  The source
         * of events generated here is always "this".
         */
        protected transient ChangeEvent changeEvent = null;

        
Inner AttributeSet implementation, which may be an
immutable unique set being shared.

/**
         * Inner AttributeSet implementation, which may be an
         * immutable unique set being shared.
         */
        private transient AttributeSet attributes;

    }

    static {
        // initialize the static key registry with the StyleConstants keys
        try {
            int n = StyleConstants.keys.length;
            for (int i = 0; i < n; i++) {
                StyleContext.registerStaticAttributeKey(StyleConstants.keys[i]);
            }
        } catch (Throwable e) {
            e.printStackTrace();
        }
    }


}