By: Rick Varella, Cuong Nguyen, & Henry Giathi

1. By: Rick Varella, Cuong Nguyen, & Henry Giathi

2. What is Books Zen Books? • Books Zen Books is an e-commerce web application designed to allow students to buy and sell their textbooks to other local students.

3. Purpose • Why sell your books to the campus bookstore and get much less money for them? • Why buy them for a premium price at the bookstore? • Why pay for shipping at an online store? • Have books that the bookstore won’t buy? • Books Zen Books solves all of that.

4. Features • Login system giving access to certain member-only features to registered users. • Advanced search options for finding books by title, author, ISBN, subject and others. • Users have full control over their listing info. • Shopping cart for saving listings of interest. • Checkout through Google Checkout or PayPal.

5. Features • Caching system for frequently accessed data. • Admin interface for managing all aspects of the system, including users, books, and settings.

6. Class Diagram

7. Usage Scenario #1: Login • Present use case while logging in to the system.

8. Usage Scenario #1: Login

9. Usage Scenario #1: Login public User checkCredentials( HttpServletRequest request ) { ResultSet result; User user = null; String email = RequestHelper.getString( "email", request ); String password = RequestHelper.getString( "password", request ); String where = "email = '" + email + "' AND password = '" + DigestHelper.md5( password ) + "'"; /* Query for matching user */ result = bzb.getDriver().select( "user", null, where ); try { /* Make sure there's a result */ if( result.next() ) { user = new User(); user.init( bzb.getDriver() ); user.populate( result ); } } catch( SQLException e ) { } return user; }

10. Usage Scenario 2: Add New Listing • Present use case while logging in to the system.

11. Usage Scenario 2: Add New Listing

12. Usage Scenario 2: Add New Listing

13. Usage Scenario 2: Add New Listing private void saveListing( BookListing listing, HttpServletRequest request ) { listing.init( bzb.getDriver() ); listing.setActive( true ); listing.setComment( RequestHelper.getString( "comment", request ) ); listing.setCondition( RequestHelper.getString( "condition", request ) ); listing.setCurrency( "usd" ); //@TODO currency should be a system setting listing.setIsbn( listing.getBook().getIsbn() ); listing.setListDate( new java.util.Date() ); listing.setPrice( RequestHelper.getDouble( "price", request ) ); listing.setUserId( ( ( User ) request.getSession().getAttribute( "authUser" ) ).getUserId() ); listing.getBook().setAuthor( listing.getBook().getAuthor().replaceAll( "\n", "|" ).trim() ); listing.save(); if( listing.getBook().isNewObject() ) { listing.getBook().save(); } }

14. Usage Scenario 3: Add Listing to Cart • Present use case while logging in to the system.

15. Usage Scenario 3: Add Listing to Cart

16. Usage Scenario 3: Add Listing to Cart result.close(); fields = new String[] { "COUNT(*) as count" }; result = bzb.getDriver().select( "shoppingcartentry", fields, where ); result.next(); if( result.getInt( "count" ) > 0 ) { isValid = false; } return isValid; } private booleanisValidListing( HttpServletRequest request ) { BookListinglisting; booleanisValid = true; String[] fields = { "*" }; String where = "listId = " + RequestHelper.getInt( "listId", request ); ResultSet result = bzb.getDriver().select( "booklisting", fields, where ); if( result.next() ) { listing = new BookListing(); listing.init( bzb.getDriver() ); listing.populate( result ); if( !listing.isActive() ) { isValid = false; } else if( listing.getUserId() == bzb.getAuthenticatedUser( request ).getUserId() ) { isValid = false; } } else { isValid = false; }

17. Third Party Tools • dom4j - http://dom4j.sourceforge.net/ • Dom4j is an open source library for working with XML and XSLT files. • We used it for reading our database configuration settings file. This makes it easier to update database details without editing source code. • Also used it for generating and reading our XML schema files for our database mapping class. This made it possible to pass a single ResultSet from the DB to an object, and the object would be populated with the result data.

18. A Sample XML Schema File <?xml version="1.0" encoding="UTF-8"?> <table name="user" className="business.User"> <field id="0" name="userId" dbType="4" javaType="int" index="pk"/> <field id="1" name="email" dbType="12" javaType="class java.lang.String"/> <field id="2" name="password" dbType="12" javaType="class java.lang.String"/> <field id="3" name="firstName" dbType="12" javaType="class java.lang.String"/> <field id="4" name="lastName" dbType="12" javaType="class java.lang.String"/> <field id="5" name="address" dbType="12" javaType="class java.lang.String"/> <field id="6" name="city" dbType="12" javaType="class java.lang.String"/> <field id="7" name="state" dbType="12" javaType="class java.lang.String"/> <field id="8" name="country" dbType="12" javaType="class java.lang.String"/> <field id="9" name="postalCode" dbType="12" javaType="class java.lang.String"/> <field id="10" name="phone" dbType="12" javaType="class java.lang.String"/> <field id="11" name="joinDate" dbType="93" javaType="class java.util.Date"/> <field id="12" name="birthDate" dbType="91" javaType="class java.util.Date"/> <field id="13" name="validated" dbType="-7" javaType="boolean"/> <field id="14" name="superUser" dbType="-7" javaType="boolean"/> <field id="15" name="validationCode" dbType="12" javaType="class java.lang.String"/> </table>

19. How dom4j Reads XML Data private SchemaColumnreadSchemaColumn( Element container ) { intcolumnId = 0; intdbType = 0; String javaType = null; String columnName = null; String index = null; Iterator<Attribute> attrIterator = container.attributeIterator(); Attribute attribute; while( attrIterator.hasNext() ) { attribute = ( Attribute )attrIterator.next(); if( attribute.getName().equals( "dbType" ) ) { dbType = Integer.parseInt( attribute.getText() ); } else if( attribute.getName().equals( "name" ) ) { columnName = attribute.getText(); } else if( attribute.getName().equals( "javaType" ) ) { javaType = attribute.getText(); } else if( attribute.getName().equals( "index" ) ) { index = attribute.getText(); } } return new SchemaColumn( columnId, columnName, dbType, javaType, index ); } public SchemaDatagetSchema( String className, Field[] fields ) { … SAXReaderreader = new SAXReader(); Document document = reader.read( file ); xmlRoot= xmlDocument.getRootElement(); columnIterator= xmlRoot.elementIterator(); while( columnIterator.hasNext() ) { columnRoot = columnIterator.next(); column = readSchemaColumn( columnRoot ); columns.put( column.getName(), column ); } … }

20. Using the Table/Class Mapping ResultSet result = bzb.getDriver().select( "shoppingcartentry e", fields, where, join, null, null, null, 0, 0 ); entry = new ShoppingCartEntry(); entry.init( bzb.getDriver() ); entry.populate( result ); public boolean populate( ResultSet row ) throws SQLException { … for( inti = 1; i <= columnCount; i++ ) { columnName = rsMetaData.getColumnName( i ); if( schema.getColumns().containsKey( columnName ) ) { setField( columnName, row ); } } } private booleansetField( String key, ResultSet row ) { SchemaColumn column = schema.getColumns().get( key ); … if( javaType.equals( "class java.lang.String" ) ) { methodTypes[0] = java.lang.String.class; methodArgs[0] = row.getString( key ); } … methodName = "set" + Util.toUpperCaseFirst( key ); method = this.getClass().getMethod( methodName, methodTypes ); method.invoke( this, methodArgs ); }

21. Problems Encountered • The NetBeans UML plugin ended up crashing NetBeans, resulting in our UML diagrams getting corrupted and unusable. • Tried out other UML programs like StarUML, Umlet, and ArgoUML, settled on the trial version of Visual Paradigm.

22. Problems Encountered • Mapping database columns to class members was troublesome. • Getting existing data out of the database and filling the objects worked without an XML schema for the most part, since we could use the column datatype from the ResultSet. • Creating new objects (ie. From user input) to insert into the DB was more difficult, since we didn’t have a ResultSet to refer to when building our queries. So for class datatypes that don’t map to the same column type (eg. Boolean  tinyint), we had issues.

23. Features That Were Not Implemented • We didn’t implement checkout. We were planning to integrate with PayPal and Google Checkout. • Administration interface. Ideally it would allow the manager to modify settings, update users and books, and change the content of strings that make up the system text. • Email validation for new accounts. Because we need an SMTP server to test it out, we did not get it working.