How to use

hasValidMaster

method

in

slimeknights.mantle.multiblock.MultiServantLogic

 protected boolean isValidSlave(World world, BlockPos pos) {
  if(!world.isBlockLoaded(pos)) {
   return false;
  }
  TileEntity te = world.getTileEntity(pos);

  // slave-blocks are only allowed if they already belong to this smeltery
  if(te instanceof MultiServantLogic) {
   MultiServantLogic slave = (MultiServantLogic) te;
   if(slave.hasValidMaster()) {
    if(!tile.getPos().equals(slave.getMasterPosition())) {
     return false;
    }
   }
  }

  return true;
 }
}

@Override
public void notifyMasterOfChange() {
 if(this.hasValidMaster()) {
  IMasterLogic logic = (IMasterLogic) this.world.getTileEntity(this.master);
  logic.notifyChange(this, this.pos);
 }
}

@Override
public boolean verifyMaster(IMasterLogic logic, World world, BlockPos pos) {
 if(this.hasMaster) {
  return this.hasValidMaster();
 }
 else {
  this.overrideMaster(pos);
  return true;
 }
}