Create library.java

Author: KercX

src/library.java

@@ -0,0 +1,61 @@
+package com.javabooks;
+
+import java.util.*;
+import java.util.stream.Collectors;
+
+public class Library implements LibraryService {
+
+    private List<Book> books = new ArrayList<>();
+
+    @Override
+    public void addBook(Book book) {
+        books.add(book);
+    }
+
+    @Override
+    public void removeBook(String isbn) {
+        books.removeIf(b -> b.getIsbn().equals(isbn));
+    }
+
+    @Override
+    public List<Book> listBooks() {
+        return new ArrayList<>(books);
+    }
+
+    @Override
+    public List<Book> searchByTitle(String title) {
+        return books.stream()
+                .filter(b -> b.getTitle().toLowerCase().contains(title.toLowerCase()))
+                .collect(Collectors.toList());
+    }
+
+    @Override
+    public List<Book> searchByAuthor(String author) {
+        return books.stream()
+                .filter(b -> b.getAuthor().toLowerCase().contains(author.toLowerCase()))
+                .collect(Collectors.toList());
+    }
+
+    @Override
+    public Book findByIsbn(String isbn) {
+        return books.stream()
+                .filter(b -> b.getIsbn().equals(isbn))
+                .findFirst().orElse(null);
+    }
+
+    @Override
+    public void borrowBook(String isbn) {
+        Book b = findByIsbn(isbn);
+        if (b != null && !b.isBorrowed()) {
+            b.borrow();
+        }
+    }
+
+    @Override
+    public void returnBook(String isbn) {
+        Book b = findByIsbn(isbn);
+        if (b != null && b.isBorrowed()) {
+            b.returnBook();
+        }
+    }
+}