Recent Question/Assignment

Your task is to implement a simple “Library Management System (LMS)” outlined below. The solution should be developed following a supplied UML class diagram, and also adhere to a purposively built test harness. The class diagram itself will be outlined during our next two online chat sessions.
The system will consist of a collection of interacting classes/interfaces to store information about:
1. The library and its library collection;
2. The holdings contained in the library collection;
3. The member who can borrow/return available holdings;
4. The borrowing history of the library member.
The system will also include a unified “front end”, through the provision of an LMSModel façade1 interface (located in the lms.model.facade package) that will offer a single point of entry for all high-level operations. This front end will support the testing of your program, independently of a graphical user interface, using the test harness.
1. LMS Scenario
The system will need to be modelled using a number of OO classes/interfaces. The main entities involved in the system, and their behaviours, are detailed below.
The library should capture information about the library collection and the library member. Note that a typical library will contain multiple collections and members, but for simplicity reasons the decision was made to ‘restrict’ the library to one library collection and one member only.
The library collection has a collection code (e.g. “LIB_IT”), a name (e.g. “Information Technology”), and a collection of holdings. The library collection is dynamic and unbounded i.e. you can add any number of holdings to a library collection.
Each holding has:
- a seven-digit numeric code (e.g. 1000001);
- a title (e.g. “Programming in Java”);
- a predefined standard loan fee ($ value);
- a maximum loan period (defined in terms of the number of days)
Also, the system needs to cater for two distinct types of Holdings, Books and Videos:
• Books have a fixed (i.e. constant) standard loan fee of $10, and a fixed (maximum) loan period of 28 days.
• Videos have a variable standard loan fee of either $4 or $6, and a fixed (maximum) loan period of 7 days.
• The formula for calculating late penalty fee is different for both Holding types as follows:
- Books: late fee = number of late days x fixed daily rate of $2.
E.g. if a given book was returned 3 days late, the late fee will be $6 (3 days x $2).
- Videos: late fee = number of late days x 50% of the standard loan fee.
E.g. if a given video with a standard loan fee of $6 was returned 3 days late, the late fee will be $9 (3 days x 50% of $6).
The member has:
- a member ID (e.g. “m00001”);
- a full name (e.g. “Joe Bloggs”);
- an initial (or maximum) borrowing credit ($ value), which is predefined according to the specific membership type, see below;
- a collection of currently borrowed holdings;
- a borrowing history comprised of the previous borrowing records.
Also, the system needs to cater for two distinct types of Members, Standard and Premium:
• Standard members have a fixed initial (or maximum) borrowing credit of $30, whereas Premium members have a fixed initial borrowing credit of $45. The holding’s standard loan fee should be deducted from member’s borrowing credit when he/she borrows this holding.
• Also, the holding return procedure, including the calculation of the late fee if applicable, will differ based on a specific member type as described in Section 3 of this document.
Borrowing History
Each borrowing record in the borrowing history should capture information about a previously returned holding and a corresponding fee payed for this holding (including late fees if applicable).
2. Base Functionality
The LMS system shall provide the following functionality. Check the provided LMSModel facade interface for a complete list of required functions:
• Create a new library, library collection, and library member
• Add/delete holding to/from a library collection
• Get a list (collection) of all the holdings in the library collection
• Count the number of holdings (books and videos) in the library collection
• Allow a member to borrow a holding
• Allow a member to return a holding
• Get a list (collection) of all currently borrowed holdings for the member
• Calculate the late fee for a holding (when applicable)
• Create and add a borrowing record to a borrowing history
• Get a specific borrowing record from a borrowing history
• Get a list of all the borrowing records (i.e. a complete borrowing history)
• Calculate the remaining credit ($ value) for a member
• Refresh member’s credit (i.e. restore the credit to the initial maximum value)
• Calculate the total late fees ($ value) accumulated by a member for all the holdings stored in the borrowing history
• Check for borrowing eligibility (see Section 3 below)
3. Additional Implementation Details and Constraints
- Your primary goal is to implement the provided LMSModel interface in a class called LMSFacade in order to provide the behaviour specified as comments in the source file and tested by the provided In Assignment 2 you will be asked to write a graphical user interface to more effectively utilise LMSModel.
- You have freedom in how you choose to implement your solution; however, you must implement it in such a way that the TestHarness is NOT modified. You should use inheritance, polymorphism, abstract classes and interfaces effectively, as taught in this course.
- Even though the LMSModel interface returns array types, you should use data structures from the Java collection API (e.g. Map, List etc.) in your implementation and convert them for return as necessary. You should choose structures that are appropriate to the task, for example if lookups are frequently performed a Map would be a suitable data structure.
- The provided source code includes DateUtil class which stores the -current- system date, and also allows you to get the total loan period (in number of days) for a holding i.e. returnDate - borrowDate. This can be useful when calculating late fees for a given holding. Specifically, the following calls should be used to find (1) the current date; and (2) the total loan period in number of days:
(1) String borrowDate = DateUtil.getInstance().getDate()); // call this when borrowing holdings
(2) int numOfDays = DateUtil.getInstance().getElapsedDays(borrowDate); // call this when returning holdings
Note that we need to artificially set the -current- date from within the TestHarness in order to test the borrow/return functions.
- You must provide appropriate constructors and methods as required by the TestHarness in order to ensure that your solution can be complied and tested without modifying the TestHarness.
Example 1. LibraryCollection class should implement the Holding[] getAllHoldings() method as used in the TestHarness tests.
Example 2. StandardMember and PremiumMember, which represent the concrete Member classes that you need to implement according to TestHarness, must have the following constructors:
public StandardMember (String memberId, String memberName);
public PremiumMember (String memberId, String memberName);
The rest of the requirements can be determined from the provided source file.
Library Collection Rules:
The library collection is dynamic and unbounded. That is, you can have an unlimited number of holdings added to the collection. When calling addHolding(…) and removeHolding(…) methods to build up the library collection, the following rules must be maintained:
• Only one copy of a given holding can be added to the collection;
• You cannot remove a holding form the collection if it is currently on loan.
Boolean values should be used to indicate the successful completion of the add/removeHolding() functions based on the above rules.
Holding Borrow/Return Rules:
The member can borrow any number of holdings as long as the following rules are followed:
• The member must have a sufficient credit available to borrow a given holding.
• The member can borrow each holding only once.
The holding return procedure differs based on a specific member type:
• Standard members are not allowed to return a (late) holding if their current balance will become negative after paying the late penalty fee. In such cases, the current credit of a member needs to be restored to the initial maximum value first.
• Premium members can return a holding even if this will result in a negative current balance. However, they won’t be able to borrow any new holdings until their current credit is restored to the initial maximum value.
Exceptions must be thrown when the holding borrow/return rules are violated. The exceptions must extend the provided LMSException class. Note: at the minimum you should provide and use three exception sub-classes:
InsufficientCreditException, MultipleBorrowingException, OverdrawnCreditException.
4. String Representations
Certain classes must provide specific string representations by overriding a public String toString() method which conforms to the format described below. This is required to enable correct operation of the TestHarness and is used as an alternative to data access methods, thereby allowing greater flexibility in how you implement your solution. Examine the TestHarness and the specification below to see how they are used.
Library Collection
e.g. LIB_IT:Information Technology:1000001,2000002
(1) holdingCodes are optional since a library collection can be empty.
e.g. LIB_IT:Information Technology would indicate an empty collection.
(2) multiple holdingCodes should be separated with comas (no space in between).
e.g. m00001:JohnSmith:25:PREMIUM
Note: type must be either “STANDARD” or “PREMIUM”.
e.g. 0000001:Introduction to Java Programming:10:28:BOOK
Note: type must be either “BOOK” or “VIDEO”.
History Record
e.g. 0000001:15
LibraryCollection, Member, Holding and HistoryRecord codes/ids and names/titles are assumed to be unique and case insensitive, and must not contain any colons (:) or commas (,) that would otherwise lead to invalidly formatted string representations.
single file for submission so you should compress your whole project (i.e. project folder in Eclipse
UML diagram next page…

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