DragSource.java 文件源码

/**
 * Deserializes this <code>DragSource</code>. This method first performs
 * default deserialization. Next, this object's <code>FlavorMap</code> is
 * deserialized by using the next object in the stream.
 * If the resulting <code>FlavorMap</code> is <code>null</code>, this
 * object's <code>FlavorMap</code> is set to the default FlavorMap for
 * this thread's <code>ClassLoader</code>.
 * Next, this object's listeners are deserialized by reading a
 * <code>null</code>-terminated sequence of 0 or more key/value pairs
 * from the stream:
 * <ul>
 * <li>If a key object is a <code>String</code> equal to
 * <code>dragSourceListenerK</code>, a <code>DragSourceListener</code> is
 * deserialized using the corresponding value object and added to this
 * <code>DragSource</code>.
 * <li>If a key object is a <code>String</code> equal to
 * <code>dragSourceMotionListenerK</code>, a
 * <code>DragSourceMotionListener</code> is deserialized using the
 * corresponding value object and added to this <code>DragSource</code>.
 * <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();
        }
    }
}