[1.7.10] onNeighborBlockChange() method question

[Thornack]

inside the onNeighborBlockChange(World world, int posX, int posY, int posZ, Block neighbourBlock) method, inside the Block Door class there are the following if statements. I have been trying to figure out what they do by breaking the code so that I can understand the door class better and how doors work. But if i remove these methods completely I dont seem to get any noticeable change. Does anyone know what these if statements do?/why are they used

 

if (world.getBlock(posX, posY + 1, posZ) != this)

            {

                world.setBlockToAir(posX, posY, posZ);

                flag = true;

            }

 

            if (!World.doesBlockHaveSolidTopSurface(world, posX, posY - 1, posZ))

            {

                world.setBlockToAir(posX, posY, posZ);

                flag = true;

 

                if (world.getBlock(posX, posY + 1, posZ) == this)

                {

                    world.setBlockToAir(posX, posY + 1, posZ);

                }

            }

[Draco18s]

Its how the bottom half of the door functions.  If the top half doesn't exist ("block above me is not also a door") then it sets itself to air (breaking the door).

Secondly, if the block below itself is not solid on top, it also breaks the door.

[Thornack]

awesome thanks! But I am confused about one other thing in this method. there is a flag and i have no idea what this flag does

boolean flag1 = world.isBlockIndirectlyGettingPowered(posX, posY, posZ) || world.isBlockIndirectlyGettingPowered(posX , posY + 1, posZ);

I know that if this flag is true the method calls a function that I suspect opens the door. But I am not sure what exactly is happening here. I know that the isBlockIndirectlyGettingPowered method checks whether any adjacent block is recieving power. but I played around with this and tried 

boolean flag1 = world.isBlockIndirectlyGettingPowered(posX, posY, posZ) || world.isBlockIndirectlyGettingPowered(posX +3, posY , posZ); 

and a block 3 blocks away in the X direction and nothing happened. (I even powered all the blocks in a square and still the door didnt open so i must have my understanding of what is going on here messed up.

 

 

[Draco18s]

That should be the door is powered / not powered so open/close the door.  The flag is telling it to run another function, so just because you powered that block over there doesn't mean the door will open: that other function may also check for power.