stylecontext.java

gcc的组建

      StringBuffer sb = new StringBuffer();
      sb.append("[StyleContext.SmallattributeSet:");
      for (int i = 0; i < attrs.length; ++i)
        {
          sb.append(" (");
          sb.append(attrs[i].toString());
          sb.append("=");
          sb.append(attrs[i+1].toString());
          sb.append(")");
        }
      sb.append("]");
      return sb.toString();
    }
  }

  // FIXME: official javadocs suggest that these might be more usefully
  // implemented using a WeakHashMap, but not sure if that works most
  // places or whether it really matters anyways.
  //
  // FIXME: also not sure if these tables ought to be static (singletons),
  // shared across all StyleContexts. I think so, but it's not clear in
  // docs. revert to non-shared if you think it matters.
  
  /**
   * The name of the default style.
   */
  public static final String DEFAULT_STYLE = "default";
  
  /**
   * The default style for this style context.
   */
  NamedStyle defaultStyle = new NamedStyle(DEFAULT_STYLE, null);
  
  static Hashtable sharedAttributeSets = new Hashtable();
  static Hashtable sharedFonts = new Hashtable();

  static StyleContext defaultStyleContext = new StyleContext();
  static final int compressionThreshold = 9;
  
  EventListenerList listenerList;
  Hashtable styleTable;
  
  /**
   * Creates a new instance of the style context. Add the default style
   * to the style table.
   */
  public StyleContext()
  {
    listenerList = new EventListenerList();
    styleTable = new Hashtable();
    styleTable.put(DEFAULT_STYLE, defaultStyle);
  }

  protected SmallAttributeSet createSmallAttributeSet(AttributeSet a)
  {
    return new SmallAttributeSet(a);
  }
  
  protected MutableAttributeSet createLargeAttributeSet(AttributeSet a)
  {
    return new SimpleAttributeSet(a);
  }

  public void addChangeListener(ChangeListener listener)
  {
    listenerList.add(ChangeListener.class, listener);
  }

  public void removeChangeListener(ChangeListener listener)
  {
    listenerList.remove(ChangeListener.class, listener);
  }

  public ChangeListener[] getChangeListeners()
  {
    return (ChangeListener[]) listenerList.getListeners(ChangeListener.class);
  }
    
  public Style addStyle(String name, Style parent)
  {
    Style newStyle = new NamedStyle(name, parent);
    if (name != null)
      styleTable.put(name, newStyle);
    return newStyle;
  }

  public void removeStyle(String name)
  {
    styleTable.remove(name);
  }

  /**
   * Get the style from the style table. If the passed name
   * matches {@link #DEFAULT_STYLE}, returns the default style.
   * Otherwise returns the previously defined style of
   * <code>null</code> if the style with the given name is not defined.
   *
   * @param name the name of the style.
   *
   * @return the style with the given name or null if no such defined.
   */
  public Style getStyle(String name)
  {
    return (Style) styleTable.get(name);
  }
  
  /**
   * Get the names of the style. The returned enumeration always
   * contains at least one member, the default style.
   */
  public Enumeration getStyleNames()
  {
    return styleTable.keys();
  }

  //
  // StyleContexts only understand the "simple" model of fonts present in
  // pre-java2d systems: fonts are a family name, a size (integral number
  // of points), and a mask of style parameters (plain, bold, italic, or
  // bold|italic). We have an inner class here called SimpleFontSpec which
  // holds such triples.
  //
  // A SimpleFontSpec can be built for *any* AttributeSet because the size,
  // family, and style keys in an AttributeSet have default values (defined
  // over in StyleConstants).
  //
  // We keep a static cache mapping SimpleFontSpecs to java.awt.Fonts, so
  // that we reuse Fonts between styles and style contexts.
  // 

  private static class SimpleFontSpec
  {
    String family;
    int style;
    int size;
    public SimpleFontSpec(String family,
                          int style,
                          int size)
    {
      this.family = family;
      this.style = style;
      this.size = size;
    }
    public boolean equals(Object obj)
    {
      return (obj != null)
        && (obj instanceof SimpleFontSpec)
        && (((SimpleFontSpec)obj).family.equals(this.family))
        && (((SimpleFontSpec)obj).style == this.style)
        && (((SimpleFontSpec)obj).size == this.size);
    }
    public int hashCode()
    {
      return family.hashCode() + style + size;
    }
  }
  
  public Font getFont(AttributeSet attr)
  {
    String family = StyleConstants.getFontFamily(attr);
    int style = Font.PLAIN;
    if (StyleConstants.isBold(attr))
      style += Font.BOLD;
    if (StyleConstants.isItalic(attr))
      style += Font.ITALIC;      
    int size = StyleConstants.getFontSize(attr);
    return getFont(family, style, size);
  }

  public Font getFont(String family, int style, int size)
  {
    SimpleFontSpec spec = new SimpleFontSpec(family, style, size);
    if (sharedFonts.containsKey(spec))
      return (Font) sharedFonts.get(spec);
    else
      {
        Font tmp = new Font(family, style, size);
        sharedFonts.put(spec, tmp);
        return tmp;
      }
  }
  
  public FontMetrics getFontMetrics(Font f)
  {
    return Toolkit.getDefaultToolkit().getFontMetrics(f);
  }

  public Color getForeground(AttributeSet a)
  {
    return StyleConstants.getForeground(a);
  }

  public Color getBackground(AttributeSet a)
  {
    return StyleConstants.getBackground(a);
  }

  protected int getCompressionThreshold() 
  {
    return compressionThreshold;
  }

  public static StyleContext getDefaultStyleContext()
  {
    return defaultStyleContext;
  }

  public AttributeSet addAttribute(AttributeSet old, Object name, Object value)
  {
    if (old instanceof MutableAttributeSet)
      {
        ((MutableAttributeSet)old).addAttribute(name, value);
        return old;
      }
    else 
      {
        MutableAttributeSet mutable = createLargeAttributeSet(old);
        mutable.addAttribute(name, value);
        if (mutable.getAttributeCount() >= getCompressionThreshold())
          return mutable;
        else
          {
            SmallAttributeSet small = createSmallAttributeSet(mutable);
            if (sharedAttributeSets.containsKey(small))
              small = (SmallAttributeSet) sharedAttributeSets.get(small);
            else
              sharedAttributeSets.put(small,small);
            return small;
          }
      }
  }

  public AttributeSet addAttributes(AttributeSet old, AttributeSet attributes)
  {
    if (old instanceof MutableAttributeSet)
      {
        ((MutableAttributeSet)old).addAttributes(attributes);
        return old;
      }
    else 
      {
        MutableAttributeSet mutable = createLargeAttributeSet(old);
        mutable.addAttributes(attributes);
        if (mutable.getAttributeCount() >= getCompressionThreshold())
          return mutable;
        else
          {
            SmallAttributeSet small = createSmallAttributeSet(mutable);
            if (sharedAttributeSets.containsKey(small))
              small = (SmallAttributeSet) sharedAttributeSets.get(small);
            else
              sharedAttributeSets.put(small,small);
            return small;
          }
      }
  }

  public AttributeSet getEmptySet()
  {
    AttributeSet e = createSmallAttributeSet(null);
    if (sharedAttributeSets.containsKey(e))
      e = (AttributeSet) sharedAttributeSets.get(e);
    else
      sharedAttributeSets.put(e, e);
    return e;
  }

  public void reclaim(AttributeSet attributes)
  {
    if (sharedAttributeSets.containsKey(attributes))
      sharedAttributeSets.remove(attributes);
  }

  public AttributeSet removeAttribute(AttributeSet old, Object name)
  {
    if (old instanceof MutableAttributeSet)
      {
        ((MutableAttributeSet)old).removeAttribute(name);
        if (old.getAttributeCount() < getCompressionThreshold())
          {
            SmallAttributeSet small = createSmallAttributeSet(old);
            if (!sharedAttributeSets.containsKey(small))
              sharedAttributeSets.put(small,small);
            old = (AttributeSet) sharedAttributeSets.get(small);
          }
        return old;
      }
    else 
      {          
        MutableAttributeSet mutable = createLargeAttributeSet(old);
        mutable.removeAttribute(name);
        SmallAttributeSet small = createSmallAttributeSet(mutable);
        if (sharedAttributeSets.containsKey(small))
          small = (SmallAttributeSet) sharedAttributeSets.get(small);
        else
          sharedAttributeSets.put(small,small);
        return small;
      }
  }

  public AttributeSet removeAttributes(AttributeSet old, AttributeSet attributes)
  {
    return removeAttributes(old, attributes.getAttributeNames());
  }

  public AttributeSet removeAttributes(AttributeSet old, Enumeration names)
  {
    if (old instanceof MutableAttributeSet)
      {
        ((MutableAttributeSet)old).removeAttributes(names);
        if (old.getAttributeCount() < getCompressionThreshold())
          {
            SmallAttributeSet small = createSmallAttributeSet(old);
            if (!sharedAttributeSets.containsKey(small))
              sharedAttributeSets.put(small,small);
            old = (AttributeSet) sharedAttributeSets.get(small);
          }
        return old;
      }
    else 
      {          
        MutableAttributeSet mutable = createLargeAttributeSet(old);
        mutable.removeAttributes(names);
        SmallAttributeSet small = createSmallAttributeSet(mutable);
        if (sharedAttributeSets.containsKey(small))
          small = (SmallAttributeSet) sharedAttributeSets.get(small);
        else
          sharedAttributeSets.put(small,small);
        return small;
      }	
  }


  // FIXME: there's some sort of quasi-serialization stuff in here which I
  // have left incomplete; I'm not sure I understand the intent properly.

  public static Object getStaticAttribute(Object key)
  {
    throw new InternalError("not implemented");
  }
  
  public static Object getStaticAttributeKey(Object key)
  {
    throw new InternalError("not implemented");
  }

  public static void readAttributeSet(ObjectInputStream in, MutableAttributeSet a)
    throws ClassNotFoundException, IOException
  {
    throw new InternalError("not implemented");
  }
  
  public static void writeAttributeSet(ObjectOutputStream out, AttributeSet a)
    throws IOException
  {
    throw new InternalError("not implemented");
  }

  public void readAttributes(ObjectInputStream in, MutableAttributeSet a)
    throws ClassNotFoundException, IOException 
  {
    throw new InternalError("not implemented");
  }

  public void writeAttributes(ObjectOutputStream out, AttributeSet a)
    throws IOException
  {
    throw new InternalError("not implemented");
  }
}