Theater Booking System – Java RMI

Overview

Theater Booking System is a distributed application that allows clients to reserve, cancel, and view seats for a theater performance via Java RMI (Remote Method Invocation). It supports concurrent clients, maintains data consistency, and provides notifications when seats become available.

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Features

• ✅ Supports multiple seat zones with independent pricing and availability.
• ✅ Clients can book and cancel seats remotely.
• ✅ Clients can view current reservations and guest lists.
• ✅ Notification mechanism: clients can subscribe for alerts when seats become available.
• ✅ Handles concurrent clients gracefully via Java RMI.

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Architecture

The application follows a Client-Server model using Java RMI.

• THClient.java: Command-line client interface for issuing booking/cancellation/list requests.
• THServer.java: Starts the server, exports the implementation, and binds it to the RMI registry.
• THImpl.java: Implements the core business logic for reservations and notifications.
• SeatType.java: Represents a seat category with price, availability, guest list, and subscriber list.
• THInterface.java: Declares the remote methods available to clients.

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Available Commands

• java THClient list <hostname>: Lists all seat zones and their current availability and price.
• java THClient book <type> <number> <name> <hostname>: Books a number of seats of the specified type for the given guest.
• java THClient cancel <type> <number> <name> <hostname>: Cancels reservations for the guest in the specified zone.
• java THClient guests <hostname>: Displays all guests and their reservations.

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Seat Zones

Code	Description	Seats	Price (€)
ΠΑ	Πλατεία - Ζώνη Α	100	50
ΠΒ	Πλατεία - Ζώνη Β	200	40
ΠΓ	Πλατεία - Ζώνη Γ	300	30
ΚΕ	Κεντρικός Εξώστης	250	35
ΠΘ	Πλαϊνά Θεωρεία	50	25

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Build & Run

Compile

javac *.java

Start RMI Registry

rmiregistry

Start the Server

java THServer

Run Client Commands

java THClient list localhost
java THClient book ΠΑ 2 Maria localhost
java THClient cancel ΠΑ 1 Maria localhost
java THClient guests localhost

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Sample Output

$ java THClient list localhost
100 θέσεις Πλατεία - Ζώνη Α (κωδικός: ΠΑ) - τιμή: 50 Ευρώ
200 θέσεις Πλατεία - Ζώνη Β (κωδικός: ΠΒ) - τιμή: 40 Ευρώ
...
$ java THClient book ΠΑ 2 Maria localhost
success: 100 euros
$ java THClient cancel ΠΑ 1 Maria localhost
success: 1 reservations left
$ java THClient guests localhost
total guests: 1
Maria (1)

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Notification Feature

• If a booking fails due to no availability, the client is asked if they wish to subscribe to notifications.
• When a cancellation frees up seats, subscribed clients are notified on their next interaction.

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