Develop a program to manage the issues that a company receive for the components of a system it owns.
The main class is IssueManager; all the classes classes are in the package ticketing.
The class Example contains a sample code that illustrates the usage of the main methods.
The exceptions thrown by the program are of type TicketException.
You can access a copy of the JDK documentation on a local server.
The method createUser() accepts a username and the set of UserClasses the user belongs to.
There are two variants of this method one accepting a Set and the other accepting
a variable list of arguments.
The method throws an exception if the username has already been created or if no user class has been specified.
Given a user name it is possible to retrieve the set of user classes for the user by means of the method getUserClasses()
The method defineComponent() creates a new top level component and adds it to the system, the method accepts a name and throws an exception if a component with the same name already exists.
The method defineSubComponent() creates a new sub-component; the method accepts the name of
the new component and the path of components and sub-components to the parent component.
It throws an exception if the
the parent component does not exist or if a sub-component of the same parent exists with the same name.
Example: given the system shown on the right, to add the new sub-component SubC the following
invocation is required: tm.defineSubComponent("SubC","/System");, while to add the sub-component
SubB.2 the following code is required: tm.defineSubComponent("SubB.2","/System/SubB");.
Given a (sub-)component it is possible to retrieve the set of sub-components names with getSubComponents() and the parent component path with getParentComponent(), this latter method return null if the component has no parent.
Please note that a path starts with '/' and contains the list of (sub-)components, starting from the top-level component, separated by '/'.
When a malfunction of some component is detected, a user can open a new ticket that contains the details about the malfunction.
A ticket is opened through the method openTicket() that requires as arguments
the user name, the path of the malfunctioning (sub-)component, a description of the failure, and
the Severity of the failure.
The method return a unique id (a positive integer starting from 1) for the ticket.
The methods throws an exception if the user name is not valid, the path does not correspond to a defined
component, or the user does not belong to the Reporter user class.
Using method getTicket() returns a Ticket object for the specific ticket id (or null if the id is not valid), while the collection of tickets can be retrieved using the method getAllTickets() that returns the list of tickets sorted by severity (from Blocking to Cosmetic, see hint below)
The class Ticket provides the getter methods getDescription(), getId(), getSeverity(), getComponent(), and getAuthor() returning description, id, severity, (sub-)component path, and user name respectively.
Hint: By constructions the enum values are objects that implement Comparable; as a consequence, a natural ordering is provided which corresponds to the order the enumerated values are declared (e.g. Blocking precedes Major, that means Ticket.Severity.Blocking.compareTo(Ticket.Severity.Major) will return a negative value )
A ticket can be in three possible states: Open, Assigned, Closed. When initially opened a ticket is in placed in state Open.
The method assignTicket() accepts a ticket id and a username, changes the ticket state to Assigned
and set the corresponding user as the assignee.
The method throws an exception if the ticket is in state Closed, the ticket id or the username
are not valid, or the user does not belong to the Maintainer user class.
The method closeTicket() accepts a ticket id and a description of the solution and sets
the state of the ticket to Closed.
The method throws an exception if the ticket is not in state Assigned.
Class Ticket provides the getter methods getState() to retrieve the current state of the ticket, and getSolutionDescription() for the description of the solution; it throws an exception if the ticket is not in the Closed state.
The method countBySeverityOfState() accepts a ticket state and returns a sorted map (keys sorted in natural order) with the number of tickets per Severity, considering only the tickets with the specific state or all tickets if the argument is null.
The method topMaintainers() returns a list strings formatted as "username:###" where username is the user name and ### is the number of closed tickets; the list is sorter by descending number of closed tickets and then by username.