Added singleton Index

src/main/java/cc/javastudio/raw/FileHandler.java

@@ -9,7 +9,6 @@ public class FileHandler implements AutoCloseable {
     private String dbFileName;
     private final int INT_LENGTH = 4;
     private final int BYTE_LENGTH = 1;
-    private HashMap<Integer, Integer> indexes = new HashMap<>();
 
     public FileHandler(String dbFileName) throws FileNotFoundException {
         this.dbFileName = dbFileName;
@@ -117,7 +116,7 @@ public class FileHandler implements AutoCloseable {
                 pos += lenRecord;
             }
             else {
-                indexes.put(idx, pos);
+                Index.getInstance().set(idx, pos);
                 //dbFile.seek(pos);   // optional: readBoolean sets pointer at pos + 1 byte
                 lenRecord = dbFile.readInt();
                 pos += INT_LENGTH;
@@ -148,8 +147,4 @@ public class FileHandler implements AutoCloseable {
     public void close() throws IOException {
         dbFile.close();
     }
-
-    public void printIndexes() {
-        System.out.println(indexes.toString());
-    }
 }

src/main/java/cc/javastudio/raw/Index.java

@@ -0,0 +1,43 @@
+package cc.javastudio.raw;
+
+import java.util.HashMap;
+
+public final class Index {
+    private static Index instance = new Index();
+    private HashMap<Long, Long> indexes = new HashMap<>();
+    private long totalRows = 0;
+    private Index() {}
+
+    public static Index getInstance() {
+        return instance;
+    }
+
+    public void set(long index, long position) {
+        if (!indexes.containsKey(index)) {
+            totalRows++;
+        }
+
+        indexes.put(index, position);
+    }
+
+    /**
+     * Searches for the position in a file of an index
+     * @param index index to find the position of
+     * @return -1 if not found; index position >= 0 when found
+     */
+    public long get(long index) {
+        return indexes.getOrDefault(index, -1l);
+        //return indexes.getOrDefault(index, (long)-1);
+    }
+
+    public long getTotalRows() {
+        return totalRows;
+    }
+
+    public void remove(long index) {
+        if (indexes.containsKey(index)) {
+            indexes.remove(index);
+            totalRows--;
+        }
+    }
+}