SiteTree tree = (SiteTree) structure;
String direction = getParameterAsString(DIRECTION);
if (direction.equals(UP)) {
tree.moveUp(getSourceDocument().getPath());
} else if (direction.equals(DOWN)) {
tree.moveDown(getSourceDocument().getPath());
} else {
throw new IllegalArgumentException("The direction [" + direction
+ "] is not supported.");
}
} else {