DragSource.java 文件源码

/**
 * Deserializes this {@code DragSource}. This method first performs
 * default deserialization. Next, this object's {@code FlavorMap} is
 * deserialized by using the next object in the stream.
 * If the resulting {@code FlavorMap} is {@code null}, this
 * object's {@code FlavorMap} is set to the default FlavorMap for
 * this thread's {@code ClassLoader}.
 * Next, this object's listeners are deserialized by reading a
 * {@code null}-terminated sequence of 0 or more key/value pairs
 * from the stream:
 * <ul>
 * <li>If a key object is a {@code String} equal to
 * {@code dragSourceListenerK}, a {@code DragSourceListener} is
 * deserialized using the corresponding value object and added to this
 * {@code DragSource}.
 * <li>If a key object is a {@code String} equal to
 * {@code dragSourceMotionListenerK}, a
 * {@code DragSourceMotionListener} is deserialized using the
 * corresponding value object and added to this {@code DragSource}.
 * <li>Otherwise, the key/value pair is skipped.
 * </ul>
 *
 * @see java.awt.datatransfer.SystemFlavorMap#getDefaultFlavorMap
 * @since 1.4
 */
private void readObject(ObjectInputStream s)
  throws ClassNotFoundException, IOException {
    s.defaultReadObject();

    // 'flavorMap' was written explicitly
    flavorMap = (FlavorMap)s.readObject();

    // Implementation assumes 'flavorMap' is never null.
    if (flavorMap == null) {
        flavorMap = SystemFlavorMap.getDefaultFlavorMap();
    }

    Object keyOrNull;
    while (null != (keyOrNull = s.readObject())) {
        String key = ((String)keyOrNull).intern();

        if (dragSourceListenerK == key) {
            addDragSourceListener((DragSourceListener)(s.readObject()));
        } else if (dragSourceMotionListenerK == key) {
            addDragSourceMotionListener(
                (DragSourceMotionListener)(s.readObject()));
        } else {
            // skip value for unrecognized key
            s.readObject();
        }
    }
}