nazunamoe/A-Star-algorithm-visualization-Java ? reverse-engineered prompt

Build me a simple Java desktop app with a Swing interface that visualizes the A star pathfinding algorithm on a grid map.

I want to be able to open a text based map file where blank spaces, walls, and one exit are represented in a very simple way, then click a button to analyze the map and start the search. The app should show the search happening step by step so I can see the path finding process, and I should be able to change the speed before or during the run.

It would also be great if I can open an editor mode after loading a map, then place or move the start point, end point, and walls directly on the grid, save those changes, and exit the editor when I am done.

Please make it clean and easy to use, and if you need to check any current Java or Swing details online, go ahead and look them up.