PlayerMovementListener.java 文件源码

/**
 * Fire a CoarsePlayerMoveEvent that wraps the given event, only if it crosses
 * a block boundary, or the PoseFlags change.
 * @param event         The movement event to potentially wrap
 * @return True if the original event was not cancelled, and a coarse event was fired,
 *         and that coarse event was cancelled. In this case, the wrapped event won't
 *         actually be cancelled, but callers should treat it like it is.
 */
private boolean callCoarsePlayerMove(final PlayerMoveEvent event) {
    // Don't fire coarse events for teleports that are not "in-game"
    // e.g. /jumpto command
    if(event instanceof PlayerTeleportEvent) {
        PlayerTeleportEvent teleportEvent = (PlayerTeleportEvent) event;
        if(teleportEvent.getCause() != TeleportCause.ENDER_PEARL &&
           teleportEvent.getCause() != TeleportCause.UNKNOWN) {
            return false;
        }
    }

    // If the movement does not cross a block boundary, and no PoseFlags changed, we don't care about it
    final EntityLocation from = event.getEntityFrom();
    final EntityLocation to = event.getEntityTo();
    if(from.position().coarseEquals(to.position()) && from.poseFlags().equals(to.poseFlags())) {
        return false;
    }

    // Remember whether the original event was already cancelled
    boolean wasCancelled = event.isCancelled();

    CoarsePlayerMoveEvent generalEvent = new CoarsePlayerMoveEvent(event, event.getPlayer(), from, to);
    this.eventBus.callEvent(generalEvent);

    if(!wasCancelled && generalEvent.isCancelled()) {
        // When a coarse event is cancelled, we have our own logic for resetting the
        // player's position, so we un-cancel the event and instead modify its
        // to location to put the player where we want them.
        resetPosition(event);
        return true;
    } else {
        return false;
    }
}