Java tutorial
/* * Copyright 2005-2008 the original author or authors. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package sample.service; import java.io.IOException; import java.net.MalformedURLException; import java.net.URL; import java.util.Collections; import java.util.Iterator; import java.util.SortedMap; import java.util.SortedSet; import java.util.TreeMap; import java.util.TreeSet; import org.apache.commons.io.IOUtils; import org.springframework.beans.BeansException; import org.springframework.beans.factory.BeanInitializationException; import org.springframework.context.support.ApplicationObjectSupport; import sample.domain.Book; public class BookServiceImpl extends ApplicationObjectSupport implements BookService { private final SortedMap<Integer, Book> books = Collections.synchronizedSortedMap(new TreeMap<Integer, Book>()); private byte[] loadPngFile(String location) { try { return IOUtils.toByteArray(getApplicationContext().getResource(location).getInputStream()); } catch (IOException e) { throw new BeanInitializationException("unable to load png file '" + location + "'", e); } } private URL toUrl(String website) { try { return new URL(website); } catch (MalformedURLException e) { throw new BeanInitializationException("unable to create URL '" + website + "'", e); } } @Override public void initApplicationContext() throws BeansException { Book book1 = new Book("Neal Stephenson", "Snow Crash", 50); book1.setCoverPng(loadPngFile("classpath:images/snowcrash.png")); book1.setWebsite(toUrl("http://en.wikipedia.org/wiki/Snow_Crash")); addBook(book1); Book book2 = new Book("William Gibson", "Neuromancer", 92); book2.setCoverPng(loadPngFile("classpath:images/neuromancer.png")); addBook(book2); Book book3 = new Book("Bruce Bethke", "Headcrash", 12); book3.setCoverPng(loadPngFile("classpath:images/headcrash.png")); addBook(book3); Book book4 = new Book("Eric S. Nylund", "Signal To Noise", 44); book4.setCoverPng(loadPngFile("classpath:images/signaltonoise.png")); addBook(book4); } public Book getBook(Integer key) { return cloneBook((Book) this.books.get(key)); } public Book getBook(int key) { return getBook(Integer.valueOf(key)); } public SortedSet<Book> getAllBooks() { TreeSet<Book> treeSet = new TreeSet<Book>(); for (Iterator<Book> i = this.books.values().iterator(); i.hasNext();) { Book book = i.next(); treeSet.add(cloneBook(book)); } return treeSet; } public int addBook(Book book) { int key; Book newBook = cloneBook(book); synchronized (books) { if (books.isEmpty()) { key = 1; } else { key = books.lastKey().intValue() + 1; } Integer keyObj = Integer.valueOf(key); newBook.setKey(keyObj); this.books.put(keyObj, newBook); } return key; } public int addBook(String author, String title, Integer count) { Book book = new Book(author, title, count); return addBook(book); } public int addBook(String author, String title, int count) { Book book = new Book(author, title, count); return addBook(book); } public void saveBook(Book book) { this.books.put(book.getKey(), cloneBook(book)); } public void deleteBook(Integer key) { this.books.remove(key); } public void deleteBook(Book book) { deleteBook(book.getKey()); } public void deleteBook(int key) { deleteBook(Integer.valueOf(key)); } private Book cloneBook(Book book) { try { if (book == null) return null; return (Book) book.clone(); } catch (CloneNotSupportedException e) { throw new IllegalStateException(e); } } }