Created
October 15, 2025 08:27
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Game of Life with Neo4j embedded.
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| ///usr/bin/env jbang "$0" "$@" ; exit $? | |
| //JAVA 25 | |
| //RUNTIME_OPTIONS --enable-native-access=ALL-UNNAMED --add-opens=java.base/java.nio=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED --add-opens=java.base/sun.nio.ch=ALL-UNNAMED --add-opens=java.base/java.util.concurrent=ALL-UNNAMED | |
| //DEPS org.neo4j:neo4j:2025.09.0 | |
| import org.neo4j.dbms.api.DatabaseManagementServiceBuilder; | |
| void main() throws IOException, InterruptedException { | |
| var height = 30; | |
| var width = 30; | |
| var sleep = Duration.ofMillis(500); | |
| var random = ThreadLocalRandom.current(); | |
| var numAlive = (int) (height * width * 0.1); | |
| var cells = random.ints(numAlive * 2, 0, height).boxed().gather(Gatherers.windowSliding(2)).toList(); | |
| try (var dbms = new DatabaseManagementServiceBuilder(Files.createTempDirectory("neo4j")).build()) { | |
| var db = dbms.database("neo4j"); | |
| db.executeTransactionally(""" | |
| UNWIND range(0,$height-1) AS row | |
| WITH row | |
| UNWIND range(0,$width-1) AS column | |
| WITH row, column | |
| CREATE (cell:Cell {coordinate: Point({x:column,y:row}), alive:false}) | |
| WITH row, column, cell | |
| UNWIND [[row-1, column-1],[row-1, column],[row-1, column+1],[row, column-1]] AS neighbor | |
| MATCH (other:Cell {coordinate: Point({x:neighbor[1],y:neighbor[0]})}) | |
| MERGE (other)-[:NEIGHBOUR_OF]->(cell) | |
| """, Map.of("height", height, "width", width)); | |
| db.executeTransactionally(""" | |
| UNWIND $cells AS cell | |
| MATCH (c:Cell {coordinate: Point({x:cell[0],y:cell[1]})}) | |
| SET c.alive = true | |
| """, Map.of("cells", cells)); | |
| var previous = ""; | |
| while (true) { | |
| var result = db.executeTransactionally(""" | |
| MATCH (cell:Cell) | |
| OPTIONAL MATCH (cell)-[:NEIGHBOUR_OF]-(:Cell {alive: true }) | |
| WITH cell, COUNT(*) AS liveNeighbours | |
| SET cell.alive = | |
| CASE liveNeighbours | |
| WHEN <= 1 THEN FALSE | |
| WHEN >= 4 THEN FALSE | |
| WHEN = 3 THEN TRUE | |
| ELSE cell.alive | |
| END | |
| WITH cell ORDER BY cell.coordinate.y ASC, cell.coordinate.x ASC | |
| WITH collect(cell) AS cells | |
| RETURN reduce(res = "", cell IN cells | res + | |
| CASE cell.coordinate.x = 0 WHEN true THEN "\\n" ELSE "" END + | |
| CASE cell.alive | |
| WHEN true THEN '\u001b[1;38;5;0;48;5;253m ■ \u001b[0m' | |
| ELSE '\u001b[1;38;5;214;48;5;253m ■ \u001b[0m' | |
| END) AS result | |
| """, Map.of(), rows -> rows.next().get("result").toString()); | |
| IO.print("\033[H\033[2J"); | |
| IO.println(result); | |
| System.out.flush(); | |
| Thread.sleep(sleep); | |
| if (result.equals(previous)) { | |
| break; | |
| } | |
| previous = result; | |
| } | |
| } | |
| } |
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