updated main

README.md

@@ -10,7 +10,9 @@ An implementation of the Log-Structured Merge Tree (LSM tree) data structure in
 4. [Benchmarks](#Benchmarks)
 5. [Implementation status](#Implementation-status)
 
-To interact with a toy tree you can use `./gradlew run`
+To interact with a toy tree you can use `./gradlew run -q` to spawn a console.
+
+![console.png](misc%2Fconsole.png)
 
 ---
 
@@ -122,7 +124,7 @@ the operation on the node. All of them have an average time complexity of `O(log
 
 ---
 
-## Benchmarks
+# Benchmarks
 
 I am using [JMH](https://openjdk.java.net/projects/code-tools/jmh/) to run benchmarks,
 the results are obtained on AMD Ryzen™ 5 4600H with 16GB of RAM and 512GB SSD.
@@ -131,7 +133,7 @@ the results are obtained on AMD Ryzen™ 5 4600H with 16GB of RAM and 512GB SSD.
 
 To run them use `./gradlew jmh`.
 
-### SSTable
+## SSTable
 
 - Negative access: the key is not present in the table, hence the Bloom filter will likely stop the search;
 - Random access: the key is present in the table, the order of the keys is random.
@@ -144,7 +146,7 @@ c.t.l.sstable.SSTableBenchmark.randomAccess    thrpt    5     7989.945 ±     40
 
 ```
 
-### Bloom filter
+## Bloom filter
 
 - Add: add keys to a 1M keys Bloom filter with 0.01 false positive rate;
 - Contains: test whether the keys are present in the Bloom filter.
@@ -156,7 +158,7 @@ c.t.l.bloom.BloomFilterBenchmark.contains      thrpt    5  3567392.634 ± 220377
 
 ```
 
-### Skip-List
+## Skip-List
 
 - Get: get keys from a 100k keys skip-list;
 - Add/Remove: add and remove keys from a 100k keys skip-list.
@@ -169,7 +171,7 @@ c.t.l.memtable.SkipListBenchmark.get           thrpt    5   487265.620 ±   8201
 
 ```
 
-### Tree
+## Tree
 
 - Get: get elements from a tree with 1M keys;
 - Add: add 1M distinct elements to a tree with a memtable size of 2^18

src/jmh/java/com/tomfran/lsm/sstable/SSTableBenchmark.java

@@ -64,13 +64,11 @@ public void setup() throws IOException {
 
             Files.createDirectory(dir);
 
-            // generate random items
             var l = new ObjectOpenHashSet<ByteArrayPair>();
             for (int i = 0; i < NUM_ITEMS * 2; i++) {
                 l.add(getRandomPair());
             }
 
-            // sort and divide into inserted and skipped
             var items = l.stream()
                          .sorted((a, b) -> ByteArrayComparator.compare(a.key(), b.key()))
                          .toList();
@@ -95,7 +93,7 @@ public void setup() throws IOException {
         }
 
         @TearDown
-        public void teardown() throws IOException {
+        public void teardown() {
             sstable.close();
             deleteDir(dir);
         }

src/jmh/java/com/tomfran/lsm/utils/BenchmarkUtils.java

@@ -3,6 +3,7 @@
 import com.tomfran.lsm.tree.LSMTree;
 import com.tomfran.lsm.types.ByteArrayPair;
 
+import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -38,17 +39,11 @@ public static void shuffleItems(ByteArrayPair[] v) {
         }
     }
 
-    public static void deleteDir(Path dir) throws IOException {
-        try (var files = Files.list(dir)) {
-            files.forEach(f -> {
-                try {
-                    Files.delete(f);
-                } catch (IOException e) {
-                    e.printStackTrace();
-                }
-            });
+    public static void deleteDir(Path dir) {
+        try (var f = Files.walk(dir)) {
+            f.map(Path::toFile).forEach(File::delete);
+        } catch (Exception ignored) {
         }
-        Files.delete(dir);
     }
 
 }

src/main/java/com/tomfran/lsm/Main.java

@@ -4,82 +4,82 @@
 import com.tomfran.lsm.types.ByteArrayPair;
 
 import java.io.File;
-import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Scanner;
+import java.util.stream.Stream;
 
 public class Main {
 
     static final String DIRECTORY = "LSM-data";
 
-    public static void main(String[] args) throws IOException {
+    public static void main(String[] args) {
 
         if (new File(DIRECTORY).exists())
             deleteDir();
 
-        LSMTree tree = new LSMTree(3, 2, DIRECTORY);
+        LSMTree tree = new LSMTree(5, 2, DIRECTORY);
 
         Scanner scanner = new Scanner(System.in);
         scanner.useDelimiter("\n");
 
-        System.out.println(
-                """
-                LSM Tree console
-
-                Commands:
-                - ins <key> <value> : insert a key-value pair
-                - get <key>         : get a value for a key
-                - del <key>         : delete a key-value pair
-                - exit              : exit the application
-
-                """
-        );
+        String intro = """
+                         
+                         |      __|   \\  |           __ __|             \s
+                         |    \\__ \\  |\\/ |   ____|      |   _| -_)   -_)\s
+                        ____| ____/ _|  _|             _| _| \\___| \\___|\s
+                       """;
+
+        String help = """
+                      Commands:
+                        - s/set  <key> <value> : insert a key-value pair;
+                        - g/get  <key>         : get a value for a key;
+                        - d/del  <key>         : delete a key-value pair;
+                        - e/exit               : exit the application;
+                        - d/help               : show this list.
+                      """;
+
+        System.out.println(intro);
+        System.out.println(help);
 
         boolean exit = false;
 
         while (!exit) {
-            System.out.print("Enter a command: ");
+            System.out.print("> ");
             String command = scanner.nextLine();
 
-            var parts = command.split(" ");
+            String[] parts = command.split(" ");
 
+            String msg;
             switch (parts[0]) {
-                case "exit" -> {
-                    System.out.println("Exiting...");
-                    exit = true;
+                case "s", "set" -> {
+                    tree.add(new ByteArrayPair(parts[1].getBytes(), parts[2].getBytes()));
+                    System.out.println("ok");
                 }
-                case "ins" -> tree.add(new ByteArrayPair(parts[1].getBytes(), parts[2].getBytes()));
-                case "del" -> tree.delete(parts[1].getBytes());
-                case "get" -> {
-                    String key = parts[1];
-                    byte[] value = tree.get(key.getBytes());
-
-                    var msg = (value == null || value.length == 0) ? "No value found for key " + key :
-                            "Value for key " + key + " is " + new String(value);
-                    System.out.println(msg);
+                case "d", "del" -> {
+                    tree.delete(parts[1].getBytes());
+                    System.out.println("ok");
                 }
-                default -> System.out.println("Unknown command: " + command);
+                case "g", "get" -> {
+                    byte[] value = tree.get(parts[1].getBytes());
+                    System.out.println((value == null || value.length == 0) ? "not found" : new String(value));
+                }
+                case "h", "help" -> System.out.println(help);
+                case "e", "exit" -> exit = true;
+                default -> System.out.println("Unknown command");
             }
-            System.out.println();
         }
         tree.stop();
         scanner.close();
 
         deleteDir();
     }
 
-    static private void deleteDir() throws IOException {
-        try (var files = Files.list(Path.of(DIRECTORY))) {
-            files.forEach(f -> {
-                try {
-                    Files.delete(f);
-                } catch (IOException e) {
-                    e.printStackTrace();
-                }
-            });
+    static private void deleteDir() {
+        try (Stream<Path> f = Files.walk(Path.of(DIRECTORY))) {
+            f.map(Path::toFile).forEach(File::delete);
+        } catch (Exception ignored) {
         }
-        Files.delete(Path.of(DIRECTORY));
     }
 
 }