multithreading

app/src/main/java/chess/ai/minimax/AlphaBetaAI.java

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+package chess.ai.minimax;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+import chess.ai.AI;
+import chess.controller.CommandExecutor;
+import chess.controller.commands.MoveCommand;
+import chess.controller.commands.PromoteCommand;
+import chess.controller.commands.PromoteCommand.PromoteType;
+import chess.model.Color;
+import chess.model.Coordinate;
+import chess.model.Move;
+
+public class AlphaBetaAI extends AI {
+
+	private final int searchDepth;
+	
+	private static final float MAX_FLOAT = Float.MAX_VALUE;
+	private static final float MIN_FLOAT = -MAX_FLOAT;
+
+	private final ExecutorService threadPool;
+
+	public AlphaBetaAI(CommandExecutor commandExecutor, Color color, int searchDepth) {
+		super(commandExecutor, color);
+		this.searchDepth = searchDepth;
+		int threadCount = Runtime.getRuntime().availableProcessors() - 1;
+		this.threadPool = Executors.newFixedThreadPool(threadCount, new AlphaBetaThreadCreator(commandExecutor, color, threadCount));
+		System.out.println();
+	}
+
+	private Move getBestMove() {
+		List<Move> moves = getAllowedMoves();
+		List<Future<Float>> moveEvaluations = new ArrayList<>(50);
+		float bestMoveValue = MIN_FLOAT;
+		Move bestMove = null;
+
+		System.out.println("Evaluating " + moves.size() + " moves ...");
+
+		for (Move move : moves) {
+			moveEvaluations.add(this.threadPool.submit(() -> {
+				return AlphaBetaThreadCreator.getMoveValue(move, this.searchDepth);
+			}));
+		}
+
+		for (int i = 0; i < moves.size(); i++) {
+			Move move = moves.get(i);
+			float value = MIN_FLOAT;
+			try {
+				value = moveEvaluations.get(i).get();
+			} catch (InterruptedException | ExecutionException e) {
+				e.printStackTrace();
+			}
+			if (value > bestMoveValue) {
+				bestMoveValue = value;
+				bestMove = move;
+			}
+		}
+
+		System.out.println("Best move : " + bestMoveValue);
+
+		return bestMove;
+	}
+
+	@Override
+	public void onGameEnd() {
+		this.threadPool.close();
+	}
+
+	@Override
+	protected void play() {
+		long current = System.currentTimeMillis();
+		Move move = getBestMove();
+		long elapsed = System.currentTimeMillis() - current;
+		System.out.println("Took " + elapsed + "ms");
+		sendCommand(new MoveCommand(move));
+	}
+
+	@Override
+	protected void promote(Coordinate pawnCoords) {
+		sendCommand(new PromoteCommand(PromoteType.Queen));
+	}
+
+}