Zzzz
372 lines
15 KiB
Java
372 lines
15 KiB
Java
package com.mzh.library.controller;
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import com.mzh.library.dao.impl.JdbcBookDao;
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import com.mzh.library.entity.AuthenticatedUser;
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import com.mzh.library.entity.Book;
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import com.mzh.library.entity.BookCategory;
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import com.mzh.library.entity.BookSearchCriteria;
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import com.mzh.library.entity.BookStatus;
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import com.mzh.library.service.BookService;
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import com.mzh.library.service.ServiceResult;
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import com.mzh.library.service.impl.BookServiceImpl;
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import com.mzh.library.util.SessionAttributes;
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import java.io.IOException;
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import java.util.Collections;
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import java.util.LinkedHashMap;
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import java.util.List;
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import java.util.Map;
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import java.util.Optional;
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import javax.servlet.ServletException;
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import javax.servlet.http.HttpServlet;
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import javax.servlet.http.HttpServletRequest;
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import javax.servlet.http.HttpServletResponse;
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import javax.servlet.http.HttpSession;
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public class BookManagementServlet extends HttpServlet {
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private static final String MANAGE_JSP = "/WEB-INF/jsp/books/manage.jsp";
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private static final String FORM_JSP = "/WEB-INF/jsp/books/form.jsp";
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private static final String UNAUTHORIZED_JSP = "/WEB-INF/jsp/auth/unauthorized.jsp";
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private static final String FLASH_SUCCESS = "flashSuccess";
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private static final String FLASH_ERROR = "flashError";
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private BookService bookService;
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@Override
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public void init() {
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this.bookService = new BookServiceImpl(new JdbcBookDao());
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}
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@Override
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protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
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String path = request.getServletPath();
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if ("/books/new".equals(path)) {
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renderForm(request, response, "Create book", "/books", new Book(), Collections.emptyMap(),
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Collections.emptyMap(), null);
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return;
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}
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if ("/books/edit".equals(path)) {
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showEditForm(request, response);
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return;
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}
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if (!"/books".equals(path)) {
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response.sendError(HttpServletResponse.SC_NOT_FOUND);
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return;
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}
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showManagementList(request, response);
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}
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@Override
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protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
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String path = request.getServletPath();
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if ("/books".equals(path)) {
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createBook(request, response);
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return;
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}
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if ("/books/update".equals(path)) {
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updateBook(request, response);
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return;
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}
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if ("/books/delete".equals(path)) {
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deleteBook(request, response);
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return;
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}
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response.sendError(HttpServletResponse.SC_NOT_FOUND);
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}
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private void showManagementList(HttpServletRequest request, HttpServletResponse response)
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throws ServletException, IOException {
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BookSearchCriteria criteria = searchCriteria(request);
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request.setAttribute("criteria", criteria);
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applyFlash(request);
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ServiceResult<List<BookCategory>> categoryResult = bookService.listCategories();
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request.setAttribute("categories", categoryResult.isSuccessful()
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? categoryResult.getData()
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: Collections.emptyList());
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if (!categoryResult.isSuccessful()) {
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request.setAttribute("errorMessage", categoryResult.getMessage());
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}
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ServiceResult<List<Book>> searchResult = bookService.searchBooks(criteria);
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request.setAttribute("books", searchResult.isSuccessful()
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? searchResult.getData()
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: Collections.emptyList());
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if (!searchResult.isSuccessful()) {
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request.setAttribute("errorMessage", searchResult.getMessage());
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request.setAttribute("errors", searchResult.getErrors());
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}
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request.getRequestDispatcher(MANAGE_JSP).forward(request, response);
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}
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private void showEditForm(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
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long id = requiredLong(request.getParameter("id"), -1L);
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ServiceResult<Optional<Book>> result = bookService.findBook(id);
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if (!result.isSuccessful() || !result.getData().isPresent()) {
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flashError(request, result.isSuccessful() ? "Book was not found." : result.getMessage());
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response.sendRedirect(request.getContextPath() + "/books");
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return;
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}
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renderForm(request, response, "Edit book", "/books/update", result.getData().get(),
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Collections.emptyMap(), Collections.emptyMap(), null);
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}
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private void createBook(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
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BookForm form = readBookForm(request, false);
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if (!form.getErrors().isEmpty()) {
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renderForm(request, response, "Create book", "/books", form.getBook(), form.getValues(),
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form.getErrors(), "Please correct the highlighted book fields.");
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return;
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}
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ServiceResult<Long> result = bookService.createBook(currentUser(request), form.getBook());
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if (!result.isSuccessful()) {
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handleFormFailure(request, response, "Create book", "/books", form, result);
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return;
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}
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flashSuccess(request, result.getMessage());
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response.sendRedirect(request.getContextPath() + "/books");
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}
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private void updateBook(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
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BookForm form = readBookForm(request, true);
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if (!form.getErrors().isEmpty()) {
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renderForm(request, response, "Edit book", "/books/update", form.getBook(), form.getValues(),
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form.getErrors(), "Please correct the highlighted book fields.");
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return;
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}
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ServiceResult<Void> result = bookService.updateBook(currentUser(request), form.getBook());
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if (!result.isSuccessful()) {
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handleFormFailure(request, response, "Edit book", "/books/update", form, result);
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return;
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}
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flashSuccess(request, result.getMessage());
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response.sendRedirect(request.getContextPath() + "/books");
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}
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private void deleteBook(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
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long id = requiredLong(request.getParameter("id"), -1L);
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ServiceResult<Void> result = bookService.deleteBook(currentUser(request), id);
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if (isPermissionDenied(result)) {
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forwardDenied(request, response, result.getMessage());
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return;
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}
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if (result.isSuccessful()) {
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flashSuccess(request, result.getMessage());
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} else {
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flashError(request, result.getMessage());
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}
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response.sendRedirect(request.getContextPath() + "/books");
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}
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private void handleFormFailure(HttpServletRequest request, HttpServletResponse response, String title,
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String action, BookForm form, ServiceResult<?> result)
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throws ServletException, IOException {
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if (isPermissionDenied(result)) {
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forwardDenied(request, response, result.getMessage());
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return;
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}
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renderForm(request, response, title, action, form.getBook(), form.getValues(), result.getErrors(),
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result.getMessage());
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}
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private void renderForm(HttpServletRequest request, HttpServletResponse response, String title, String action,
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Book book, Map<String, String> formValues, Map<String, String> errors, String errorMessage)
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throws ServletException, IOException {
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ServiceResult<List<BookCategory>> categoryResult = bookService.listCategories();
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request.setAttribute("categories", categoryResult.isSuccessful()
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? categoryResult.getData()
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: Collections.emptyList());
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request.setAttribute("statuses", BookStatus.values());
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request.setAttribute("formTitle", title);
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request.setAttribute("formAction", action);
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request.setAttribute("book", book);
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request.setAttribute("formValues", formValues);
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request.setAttribute("errors", errors);
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if (errorMessage != null && !errorMessage.isEmpty()) {
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request.setAttribute("errorMessage", errorMessage);
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} else if (!categoryResult.isSuccessful()) {
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request.setAttribute("errorMessage", categoryResult.getMessage());
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}
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request.getRequestDispatcher(FORM_JSP).forward(request, response);
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}
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private BookForm readBookForm(HttpServletRequest request, boolean requireId) {
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Map<String, String> values = formValues(request);
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Map<String, String> errors = new LinkedHashMap<>();
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Book book = new Book();
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if (requireId) {
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book.setId(parseLong(values.get("id"), "id", "Select a valid book.", errors));
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}
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book.setIdentifier(values.get("identifier"));
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book.setTitle(values.get("title"));
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book.setAuthor(values.get("author"));
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book.setCategoryId(parseLong(values.get("categoryId"), "categoryId", "Select a category.", errors));
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book.setTotalCopies(parseInt(values.get("totalCopies"), "totalCopies", "Enter a valid total copy count.", errors));
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book.setAvailableCopies(parseInt(values.get("availableCopies"), "availableCopies",
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"Enter a valid available copy count.", errors));
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try {
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book.setStatus(BookStatus.fromCode(values.get("status")));
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} catch (IllegalArgumentException ex) {
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errors.put("status", "Select a status.");
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}
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return new BookForm(book, values, errors);
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}
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private Map<String, String> formValues(HttpServletRequest request) {
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Map<String, String> values = new LinkedHashMap<>();
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values.put("id", trim(request.getParameter("id")));
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values.put("identifier", trim(request.getParameter("identifier")));
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values.put("title", trim(request.getParameter("title")));
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values.put("author", trim(request.getParameter("author")));
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values.put("categoryId", trim(request.getParameter("categoryId")));
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values.put("totalCopies", trim(request.getParameter("totalCopies")));
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values.put("availableCopies", trim(request.getParameter("availableCopies")));
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values.put("status", trim(request.getParameter("status")));
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return values;
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}
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private BookSearchCriteria searchCriteria(HttpServletRequest request) {
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return new BookSearchCriteria(
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request.getParameter("identifier"),
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request.getParameter("title"),
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request.getParameter("author"),
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optionalLong(request.getParameter("categoryId"))
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);
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}
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private Long optionalLong(String value) {
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String trimmed = trim(value);
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if (trimmed.isEmpty()) {
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return null;
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}
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try {
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return Long.valueOf(trimmed);
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} catch (NumberFormatException ex) {
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return -1L;
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}
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}
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private long parseLong(String value, String field, String message, Map<String, String> errors) {
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String trimmed = trim(value);
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if (trimmed.isEmpty()) {
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errors.put(field, message);
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return 0L;
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}
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try {
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long parsed = Long.parseLong(trimmed);
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if (parsed <= 0) {
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errors.put(field, message);
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}
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return parsed;
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} catch (NumberFormatException ex) {
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errors.put(field, message);
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return 0L;
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}
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}
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private int parseInt(String value, String field, String message, Map<String, String> errors) {
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String trimmed = trim(value);
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if (trimmed.isEmpty()) {
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errors.put(field, message);
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return -1;
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}
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try {
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return Integer.parseInt(trimmed);
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} catch (NumberFormatException ex) {
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errors.put(field, message);
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return -1;
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}
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}
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private long requiredLong(String value, long fallback) {
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try {
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long parsed = Long.parseLong(trim(value));
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return parsed > 0 ? parsed : fallback;
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} catch (NumberFormatException ex) {
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return fallback;
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}
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}
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private boolean isPermissionDenied(ServiceResult<?> result) {
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return !result.isSuccessful() && "You do not have permission to manage books.".equals(result.getMessage());
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}
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private void forwardDenied(HttpServletRequest request, HttpServletResponse response, String message)
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throws ServletException, IOException {
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response.setStatus(HttpServletResponse.SC_FORBIDDEN);
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request.setAttribute("errorMessage", message);
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request.getRequestDispatcher(UNAUTHORIZED_JSP).forward(request, response);
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}
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private AuthenticatedUser currentUser(HttpServletRequest request) {
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HttpSession session = request.getSession(false);
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Object value = session == null ? null : session.getAttribute(SessionAttributes.AUTHENTICATED_USER);
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return value instanceof AuthenticatedUser ? (AuthenticatedUser) value : null;
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}
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private void applyFlash(HttpServletRequest request) {
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HttpSession session = request.getSession(false);
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if (session == null) {
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return;
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}
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moveFlash(session, request, FLASH_SUCCESS, "successMessage");
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moveFlash(session, request, FLASH_ERROR, "errorMessage");
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}
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private void moveFlash(HttpSession session, HttpServletRequest request, String sessionKey, String requestKey) {
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Object value = session.getAttribute(sessionKey);
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if (value != null) {
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request.setAttribute(requestKey, value);
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session.removeAttribute(sessionKey);
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}
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}
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private void flashSuccess(HttpServletRequest request, String message) {
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request.getSession().setAttribute(FLASH_SUCCESS, message);
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}
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private void flashError(HttpServletRequest request, String message) {
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request.getSession().setAttribute(FLASH_ERROR, message);
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}
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private String trim(String value) {
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return value == null ? "" : value.trim();
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}
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private static final class BookForm {
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private final Book book;
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private final Map<String, String> values;
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private final Map<String, String> errors;
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private BookForm(Book book, Map<String, String> values, Map<String, String> errors) {
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this.book = book;
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this.values = values;
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this.errors = errors;
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}
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private Book getBook() {
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return book;
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}
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private Map<String, String> getValues() {
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return values;
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}
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private Map<String, String> getErrors() {
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return errors;
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}
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}
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}
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