Implement Author entity: re-format parts of table structures, add

supporting code
Signed-off-by: Pekka Helenius <fincer89@hotmail.com>

bookstore/src/main/java/com/fjordtek/bookstore/BookstoreApplication.java

@@ -12,6 +12,8 @@ import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;
 import org.springframework.context.annotation.Bean;
 
+import com.fjordtek.bookstore.model.Author;
+import com.fjordtek.bookstore.model.AuthorRepository;
 import com.fjordtek.bookstore.model.Book;
 import com.fjordtek.bookstore.model.BookRepository;
 import com.fjordtek.bookstore.model.Category;
@@ -26,7 +28,11 @@ public class BookstoreApplication extends SpringBootServletInitializer {
 	}
 
 	@Bean
-	public CommandLineRunner bookDatabaseRunner(BookRepository bookRepository, CategoryRepository categoryRepository) {
+	public CommandLineRunner bookDatabaseRunner(
+			BookRepository bookRepository,
+			CategoryRepository categoryRepository,
+			AuthorRepository authorRepository
+			) {
 
 		return (args) -> {
 
@@ -36,11 +42,16 @@ public class BookstoreApplication extends SpringBootServletInitializer {
 			categoryRepository.save(new Category("Fantasy"));
 			categoryRepository.save(new Category("Sci-Fi"));
 
+			authorRepository.save(new Author("Angela","Carter"));
+			authorRepository.save(new Author("Andrzej","Sapkowski"));
+
 			commonLogger.info("Add new sample books to database");
 
 			bookRepository.save(new Book(
 					"Bloody Chamber",
-					"Angela Carter",
+					authorRepository.findByFirstNameIgnoreCaseContainingAndLastNameIgnoreCaseContaining(
+							"Angela","Carter"
+							).get(0),
 					1979,
 					"1231231-12",
 					new BigDecimal("18.00"),
@@ -48,7 +59,9 @@ public class BookstoreApplication extends SpringBootServletInitializer {
 					));
 			bookRepository.save(new Book(
 					"The Witcher: The Lady of the Lake",
-					"Andrzej Sapkowski",
+					authorRepository.findByFirstNameIgnoreCaseContainingAndLastNameIgnoreCaseContaining(
+							"Andrzej","Sapkowski"
+							).get(0),
 					1999,
 					"3213221-3",
 					new BigDecimal("19.99"),
@@ -60,6 +73,10 @@ public class BookstoreApplication extends SpringBootServletInitializer {
 			for (Category category : categoryRepository.findAll()) {
 				commonLogger.info(category.toString());
 			}
+			commonLogger.info("Sample authors in the database");
+			for (Author author : authorRepository.findAll()) {
+				commonLogger.info(author.toString());
+			}
 			commonLogger.info("Sample books in the database");
 			for (Book book : bookRepository.findAll()) {
 				commonLogger.info(book.toString());

bookstore/src/main/java/com/fjordtek/bookstore/model/Author.java

@@ -0,0 +1,147 @@
+package com.fjordtek.bookstore.model;
+
+import java.util.List;
+
+import javax.persistence.CascadeType;
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.FetchType;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.OneToMany;
+import javax.persistence.SequenceGenerator;
+import javax.validation.constraints.NotBlank;
+import javax.validation.constraints.Pattern;
+import javax.validation.constraints.Size;
+
+import com.fasterxml.jackson.annotation.JsonIgnore;
+
+@Entity
+public class Author {
+
+	private static final int strMin         = 2;
+	private static final int strMax         = 100;
+	// We format length check in Size annotation, not here
+	private static final String regexCommon = "^[a-zA-Z0-9\\-:\\s]*$";
+
+	////////////////////
+	// Primary key value in database
+
+	@Id
+	@GeneratedValue(
+			strategy     = GenerationType.IDENTITY,
+			generator    = "authorIdGenerator"
+			)
+	@SequenceGenerator(
+			name         = "authorIdGenerator",
+			sequenceName = "authorIdSequence"
+			)
+	@JsonIgnore
+    private Long id;
+
+	//////////
+	@Column(name = "firstname", nullable = false)
+	@Size(
+			min = strMin, max = strMax,
+			message = "First name length must be " + strMin + "-" + strMax + " characters"
+			)
+	@NotBlank(
+			message = "Fill the first name form"
+			)
+	@Pattern(
+			regexp  = regexCommon,
+			message = "Invalid characters"
+			)
+	private String firstName;
+
+	//////////
+	@Column(name = "lastname", nullable = false)
+	@Size(
+			min = strMin, max = strMax,
+			message = "Last name length must be " + strMin + "-" + strMax + " characters"
+			)
+	@NotBlank(
+			message = "Fill the first name form"
+			)
+	@Pattern(
+			regexp  = regexCommon,
+			message = "Invalid characters"
+			)
+	private String lastName;
+
+	// Omit from Jackson JSON serialization
+	//@JsonBackReference(value = "books")
+
+	@JsonIgnore
+	@OneToMany(
+			mappedBy     = "author",
+			// We consider EAGER FetchType for updatable tables, i.e. when adding new author
+			fetch        = FetchType.EAGER,
+			cascade      = CascadeType.ALL,
+			targetEntity = Book.class
+			)
+	private List<Book> books;
+
+	////////////////////
+	// Attribute setters
+
+	public void setId(Long id) {
+		this.id = id;
+	}
+
+	public void setFirstName(String firstName) {
+		// Delete leading & trailing whitespaces (typos from user)
+		this.firstName = firstName.trim();
+	}
+
+	public void setLastName(String lastName) {
+		// Delete leading & trailing whitespaces (typos from user)
+		this.lastName = lastName.trim();
+	}
+
+	public void setBooks(List<Book> books) {
+		this.books = books;
+	}
+
+	////////////////////
+	// Attribute getters
+
+	public Long getId() {
+		return id;
+	}
+
+	public String getFirstName() {
+		return firstName;
+	}
+
+	public String getLastName() {
+		return lastName;
+	}
+
+	public List<Book> getBooks() {
+		return books;
+	}
+
+	////////////////////
+	// Class constructors
+
+	public Author() {}
+
+	public Author(String firstName, String lastName) {
+		// super();
+	    this.firstName  = firstName;
+	    this.lastName   = lastName;
+	}
+
+	////////////////////
+	// Class overrides
+
+	@Override
+	public String toString() {
+		return "[" + "id: "   + this.id        + ", " +
+			   "firstname: "  + this.firstName + ", " +
+			   "lastname: "   + this.lastName  + "]";
+	}
+
+}

bookstore/src/main/java/com/fjordtek/bookstore/model/AuthorJsonSerializer.java

@@ -0,0 +1,31 @@
+package com.fjordtek.bookstore.model;
+
+import java.io.IOException;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.fasterxml.jackson.databind.ser.std.StdSerializer;
+
+public class AuthorJsonSerializer extends StdSerializer<Author> {
+	private static final long serialVersionUID = 5233819344225306443L;
+
+	public AuthorJsonSerializer() {
+		this(null);
+	}
+
+	public AuthorJsonSerializer(Class<Author> jd) {
+		super(jd);
+	}
+
+	@Override
+	public void serialize(Author author, JsonGenerator gen, SerializerProvider provider)
+			throws IOException {
+				gen.writeStartObject();
+				// Author class Id has JsonIgnore annotation
+				//gen.writeFieldId(author.getId());
+				gen.writeStringField("firstname", author.getFirstName());
+				gen.writeStringField("lastname", author.getLastName());
+				gen.writeEndObject();
+	}
+
+}

bookstore/src/main/java/com/fjordtek/bookstore/model/AuthorRepository.java

@@ -0,0 +1,22 @@
+package com.fjordtek.bookstore.model;
+
+import java.util.List;
+
+import org.springframework.data.repository.CrudRepository;
+import org.springframework.data.repository.query.Param;
+import org.springframework.data.rest.core.annotation.RepositoryRestResource;
+import org.springframework.data.rest.core.annotation.RestResource;
+
+@RepositoryRestResource(
+		path            = "authors",
+		itemResourceRel = "authors",
+		exported        = true
+		)
+public interface AuthorRepository extends CrudRepository<Author,Long> {
+
+	@RestResource(path = "author", rel = "author")
+	public List<Author> findByFirstNameIgnoreCaseContainingAndLastNameIgnoreCaseContaining(
+			@Param("firstname") String firstName, @Param("lastname") String lastName
+			);
+
+}

bookstore/src/main/java/com/fjordtek/bookstore/model/Book.java

@@ -98,19 +98,24 @@ public class Book {
 	private String title;
 
 	//////////
-	@Column(nullable = false)
-	@Size(
-			min = strMin, max = strMax,
-			message = "Author length must be " + strMin + "-" + strMax + " characters"
-			)
-	@NotBlank(
-			message = "Fill the book author form"
-			)
-	@Pattern(
-			regexp  = regexCommon,
-			message = "Invalid characters"
+	// If category is null, we do not print it in JSON output.
+	@JsonUnwrapped
+
+	/*
+	 * There are many ways to filter which category fields we want to JSON output.
+	 * Using a custom JSON serializer is one of them.
+	 */
+	@JsonSerialize(using = AuthorJsonSerializer.class)
+	@ManyToOne(
+			fetch        = FetchType.EAGER,
+			optional     = true,
+			targetEntity = Author.class
 			)
-	private String author;
+    @JoinColumn(
+    		name     = "author_id",
+    		nullable = true
+    		)
+	private Author author;
 
 	//////////
 	// TODO: Prefer Timestamp data type
@@ -175,8 +180,9 @@ public class Book {
 	 */
 	@JsonSerialize(using = CategoryJsonSerializer.class)
 	@ManyToOne(
-			fetch    = FetchType.EAGER,
-			optional = true
+			fetch        = FetchType.EAGER,
+			optional     = true,
+			targetEntity = Category.class
 			)
     @JoinColumn(
     		name     = "category_id",
@@ -198,7 +204,7 @@ public class Book {
 		this.title = title;
 	}
 
-	public void setAuthor(String author) {
+	public void setAuthor(Author author) {
 		this.author = author;
 	}
 
@@ -231,7 +237,7 @@ public class Book {
 		return title;
 	}
 
-	public String getAuthor() {
+	public Author getAuthor() {
 		return author;
 	}
 
@@ -256,7 +262,7 @@ public class Book {
 
 	public Book() {}
 
-	public Book(String title, String author, int year, String isbn, BigDecimal price, Category category) {
+	public Book(String title, Author author, int year, String isbn, BigDecimal price, Category category) {
 		// super();
 	    this.title    = title;
 	    this.author   = author;

bookstore/src/main/java/com/fjordtek/bookstore/model/Category.java

@@ -43,8 +43,8 @@ public class Category {
 	@OneToMany(
 			mappedBy     = "category",
 			fetch        = FetchType.LAZY,
-			cascade      = CascadeType.ALL
-			//targetEntity = Book.class
+			cascade      = CascadeType.ALL,
+			targetEntity = Book.class
 			)
 	private List<Book> books;
 

bookstore/src/main/java/com/fjordtek/bookstore/web/BookController.java

@@ -25,6 +25,8 @@ import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.bind.annotation.ResponseStatus;
 
+import com.fjordtek.bookstore.model.Author;
+import com.fjordtek.bookstore.model.AuthorRepository;
 import com.fjordtek.bookstore.model.Book;
 import com.fjordtek.bookstore.model.BookRepository;
 import com.fjordtek.bookstore.model.CategoryRepository;
@@ -41,10 +43,13 @@ public class BookController {
 	}
 
 	@Autowired
-	private BookRepository       bookRepository;
+	private CategoryRepository   categoryRepository;
 
 	@Autowired
-	private CategoryRepository   categoryRepository;
+	private AuthorRepository     authorRepository;
+
+	@Autowired
+	private BookRepository       bookRepository;
 
 	private static final String RestJSONPageView      = "json";
 	private static final String RestAPIRefPageView    = "apiref";
@@ -76,6 +81,38 @@ public class BookController {
 		// Security implications of adding these all controller-wide?
 		dataModel.addAllAttributes(globalModelMap);
 		dataModel.addAttribute("categories", categoryRepository.findAll());
+		dataModel.addAttribute("authors", authorRepository.findAll());
+	}
+
+	//////////////////////////////
+	// Private methods
+
+	private void detectAndSaveBookAuthor(Book book) {
+		/*
+		 * Find an author from the current AUTHOR table by his/her first and last name.
+		 * In CrudRepository, if Id attribute is not found, it is stored
+		 * as a new row value. Therefore, it's crucial to identify whether row value already
+		 * exists in AUTHOR table.
+		 */
+
+		try {
+			Author authorI = authorRepository.findByFirstNameIgnoreCaseContainingAndLastNameIgnoreCaseContaining(
+					book.getAuthor().getFirstName(),book.getAuthor().getLastName())
+					.get(0);
+
+			/*
+			 * When author is found, use it's Id attribute for book's author Id...
+			 */
+			book.getAuthor().setId(authorI.getId());
+
+			/*
+			 * ...Otherwise, consider this a new author and store it appropriately.
+			 * Actually, when author is not found, we get IndexOutOfBoundsException.
+			 */
+		} catch (IndexOutOfBoundsException e) {
+			authorRepository.save(book.getAuthor());
+		}
+
 	}
 
 	//////////////////////////////
@@ -144,8 +181,10 @@ public class BookController {
 
 		httpServerLogger.log(requestData, responseData);
 
+		detectAndSaveBookAuthor(book);
 		bookRepository.save(book);
 
+
 		return "redirect:" + bookListPageView;
 	}
 
@@ -231,6 +270,8 @@ public class BookController {
 			return bookEditPageView;
 		}
 
+
+		detectAndSaveBookAuthor(book);
 		bookRepository.save(book);
 
 		httpServerLogger.log(requestData, responseData);