making a glass outline

I want to surround the area between 2 blocks with glass. I tried this but it didn't work at all

Code:java

int x1 = block1.getX();
int z1 = block1.getZ();
int x2 = block2.getX();
int z2 = block2.getZ();
int startx = x1;
int endx = x2;
int startz = z1;
int endz = z2;
if (x1 >= x2){
startx = x2;
endx = x1;
}
if (z1 >= z2){
startx = z2;
endx = z1;
}
for (int xx = startx; xx < endx; xx++){
for (int zz = startz; zz < endz; zz++){
int yy = block1.getWorld().getHighestBlockYAt(xx, zz);
Block b = block1.getWorld().getBlockAt(xx, yy, zz);
if (b.getX() == startx || b.getX() == endx){
b.setType(Material.GLASS);
}
if (b.getZ() == startz || b.getZ() == endz){
b.setType(Material.GLASS);
}
}
}
}

Can someone help me with this? tell me how or at least what I am doing wrong.

 

You could look at the world edit source,

 

Have you seen that source code? I can't understand like any of it. It's way to much for me to handle haha

 

Just looked at it... *Mind Blown*

 

Prepare to be amazed...
https://github.com/sk89q/worldedit/tree/master/src/main/java/com/sk89q/