Create jsonstorage.java

Author: KercX

src/jsonstorage.java

@@ -0,0 +1,66 @@
+package com.javabooks;
+
+import java.io.*;
+import java.util.*;
+
+public class JsonStorage implements BookStorage {
+
+    @Override
+    public void save(List<Book> books) throws IOException {
+        BufferedWriter w = new BufferedWriter(new FileWriter("books.json"));
+        w.write("[\n");
+        for (int i = 0; i < books.size(); i++){
+            Book b = books.get(i);
+            w.write("  {\n");
+            w.write("    \"title\": \"" + b.getTitle() + "\",\n");
+            w.write("    \"author\": \"" + b.getAuthor() + "\",\n");
+            w.write("    \"year\": " + b.getYear() + ",\n");
+            w.write("    \"isbn\": \"" + b.getIsbn() + "\",\n");
+            w.write("    \"borrowed\": " + b.isBorrowed() + "\n");
+            w.write("  }" + (i < books.size() - 1 ? "," : "") + "\n");
+        }
+        w.write("]");
+        w.close();
+    }
+
+    @Override
+    public List<Book> load() throws IOException {
+        List<Book> list = new ArrayList<>();
+        File f = new File("books.json");
+        if (!f.exists()) return list;
+
+        BufferedReader r = new BufferedReader(new FileReader(f));
+        String json = r.lines().reduce("", (a, b) -> a + b);
+        r.close();
+
+        json = json.replace("[", "").replace("]", "");
+        String[] entries = json.split("\\},\\{");
+
+        for (String e : entries){
+            String clean = e.replace("{", "").replace("}", "");
+            String[] parts = clean.split(",");
+
+            Map<String, String> map = new HashMap<>();
+
+            for (String p : parts){
+                String[] kv = p.split(":", 2);
+                map.put(
+                        kv[0].replace("\"", "").trim(),
+                        kv[1].replace("\"", "").trim()
+                );
+            }
+
+            Book b = new Book(
+                    map.get("title"),
+                    map.get("author"),
+                    Integer.parseInt(map.get("year")),
+                    map.get("isbn")
+            );
+
+            if (Boolean.parseBoolean(map.get("borrowed"))) b.borrow();
+
+            list.add(b);
+        }
+        return list;
+    }
+}