Dynamic hash zeroes

src/Main.java

@@ -1,27 +1,30 @@
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Scanner;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
 import java.util.stream.IntStream;
 import model.BlockChain;
 import model.Miner;
 
 public final class Main {
+
     public static void main(final String[] args) throws InterruptedException {
-        final var sc = new Scanner(System.in);
-        System.out.print("Enter how many zeros the hash must start with: ");
-        final var hashZeroes = sc.nextInt();
-        final var blockChain = new BlockChain(hashZeroes);
+        final var blockChain = new BlockChain();
         blockChain.load();
 
-        final List<Miner> miners = new ArrayList<>();
-        IntStream.range(0, 5).forEach(minerId -> miners.add(new Miner(minerId, blockChain)));
-        miners.forEach(Thread::start);
+        final var nThreads = Runtime.getRuntime().availableProcessors();
+        final var executor = Executors.newFixedThreadPool(nThreads);
 
-        for (final Miner miner : miners) {
-            miner.join();
+        IntStream.range(0, 5)
+            .mapToObj(minerId -> new Miner(minerId, blockChain))
+            .forEach(executor::submit);
+
+        executor.shutdown();
+
+        if (!executor.awaitTermination(60, TimeUnit.SECONDS)) {
+            executor.shutdownNow();
         }
 
-        System.out.println(blockChain);
         blockChain.save();
     }
+
 }
+

src/model/Block.java

@@ -37,6 +37,10 @@ public class Block implements Serializable {
     return previousBlockHash;
   }
 
+  public float getGenerationSecs() {
+    return generationSecs;
+  }
+
   private String calculateBlockHash() {
     final long start = System.currentTimeMillis();
     var hash = "";
@@ -61,7 +65,7 @@ public class Block implements Serializable {
         + "Magic number: " + this.magicNumber + "\n"
         + "Hash of the previous block: " + "\n" + this.previousBlockHash + "\n"
         + "Hash of the block: \n" + this.blockHash + "\n"
-        + "Block was generating for: " + this.generationSecs + " seconds" + "\n";
+        + "Block was generating for " + this.generationSecs + " seconds";
   }
-}
 
+}

src/model/BlockChain.java

@@ -6,17 +6,32 @@ import java.util.List;
 import java.util.stream.Collectors;
 
 public class BlockChain {
-  private final int hashZeroes;
-  private static final List<Block> blockList = new LinkedList<>();
 
-  public BlockChain(final int hashZeroes) {
-    this.hashZeroes = hashZeroes;
-  }
+  private int hashZeroes;
+  private static final List<Block> blockList = new LinkedList<>();
 
   public synchronized void addBlock(final int minerId) {
     final int nextId = blockList.size();
     final String previousBlockHash = (nextId > 0) ? blockList.get(nextId - 1).getBlockHash() : "0";
-    blockList.add(new Block(previousBlockHash, minerId, nextId, hashZeroes));
+
+    final var block = new Block(previousBlockHash, minerId, nextId, hashZeroes);
+    blockList.add(block);
+
+    final float generationTime = blockList.get(nextId).getGenerationSecs();
+    final String CASE;
+
+    if (generationTime < 10) {
+      hashZeroes += 1;
+      CASE = "N was increased to " + hashZeroes + "\n";
+    } else if (generationTime > 60) {
+      hashZeroes -= 1;
+      CASE = "N was decreased by 1" + "\n";
+    } else {
+      CASE = "N stays the same";
+    }
+
+    System.out.println(block);
+    System.out.println(CASE);
   }
 
   public boolean validateBlockchain() {
@@ -51,4 +66,5 @@ public class BlockChain {
   public void save() {
     FileManagement.saveBlockchain(blockList);
   }
+
 }

src/model/Miner.java

@@ -1,6 +1,6 @@
 package model;
 
-public class Miner extends Thread {
+public class Miner implements Runnable {
 
   private final int minerId;
   private final BlockChain blockChain;
@@ -14,4 +14,5 @@ public class Miner extends Thread {
   public void run() {
     blockChain.addBlock(minerId);
   }
+
 }

src/util/FileManagement.java

@@ -39,4 +39,5 @@ public final class FileManagement {
       }
     }
   }
+
 }