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public enum FontEffect {
BOLD, ITALIC, SUPERSCRIPT, SUBSCRIPT, STRIKETHROUGH
}
public final class FontData {
/**
* A weak hash map will drop unused references to FontData.
* Values have to be wrapped in WeakReferences,
* because value objects in weak hash map are held by strong references.
*/
private static final WeakHashMap<FontData, WeakReference<FontData>> FLY_WEIGHT_DATA =
new WeakHashMap<FontData, WeakReference<FontData>>();
private final int pointSize;
private final String fontFace;
private final Color color;
private final Set<FontEffect> effects;
private FontData(int pointSize, String fontFace, Color color, EnumSet<FontEffect> effects) {
this.pointSize = pointSize;
this.fontFace = fontFace;
this.color = color;
this.effects = Collections.unmodifiableSet(effects);
}
public static FontData create(int pointSize, String fontFace, Color color,
FontEffect... effects) {
EnumSet<FontEffect> effectsSet = EnumSet.noneOf(FontEffect.class);
for (FontEffect fontEffect : effects) {
effectsSet.add(fontEffect);
}
// We are unconcerned with object creation cost, we are reducing overall memory consumption
FontData data = new FontData(pointSize, fontFace, color, effectsSet);
// Retrieve previously created instance with the given values if it (still) exists
WeakReference<FontData> ref = FLY_WEIGHT_DATA.get(data);
FontData result = (ref != null) ? ref.get() : null;
// Store new font data instance if no matching instance exists
if (result == null) {
FLY_WEIGHT_DATA.put(data, new WeakReference<FontData> (data));
result = data;
}
// return the single immutable copy with the given values
return result;
}
@Override
public boolean equals(Object obj) {
if (obj instanceof FontData) {
if (obj == this) {
return true;
}
FontData other = (FontData) obj;
return other.pointSize == pointSize && other.fontFace.equals(fontFace)
&& other.color.equals(color) && other.effects.equals(effects);
}
return false;
}
@Override
public int hashCode() {
return (pointSize * 37 + effects.hashCode() * 13) * fontFace.hashCode();
}
// Getters for the font data, but no setters. FontData is immutable.
}
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