https://github.com/tharindu714/programmatical-timer-j2ee
A Java EE application showcasing the use of programmatic timers via the TimerService API.
https://github.com/tharindu714/programmatical-timer-j2ee
j2ee java timer
Last synced: 5 months ago
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A Java EE application showcasing the use of programmatic timers via the TimerService API.
- Host: GitHub
- URL: https://github.com/tharindu714/programmatical-timer-j2ee
- Owner: Tharindu714
- Created: 2025-06-14T10:47:12.000Z (7 months ago)
- Default Branch: main
- Last Pushed: 2025-06-14T11:24:38.000Z (7 months ago)
- Last Synced: 2025-06-14T11:34:53.034Z (7 months ago)
- Topics: j2ee, java, timer
- Language: Java
- Homepage:
- Size: 0 Bytes
- Stars: 1
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
# ⏱️ Programmatic Timer EJB Demo
> A Java EE application showcasing the use of programmatic timers via the `TimerService` API.
---
## 📑 Table of Contents
1. [✨ Project Overview](#-project-overview)
2. [📂 Source Structure](#-source-structure)
3. [🛠️ Technologies & Dependencies](#️-technologies--dependencies)
4. [🚀 Getting Started](#-getting-started)
* [Prerequisites](#-prerequisites)
* [Clone & Build](#-clone--build)
* [Deploy & Run](#-deploy--run)
5. [🔧 Configuration](#-configuration)
6. [📚 Core Components](#-core-components)
* [TimerBean (EJB)](#timerbean-ejb)
* [REST Interface](#rest-interface)
7. [📄 API Endpoints](#-api-endpoints)
8. [🔄 Timer Workflow](#-timer-workflow)
9. [🛡️ Error Handling & Logging](#️-error-handling--logging)
10. [🤝 Contributing](#-contributing)
11. [📜 License](#-license)
---
## ✨ Project Overview
This sample J2EE application illustrates creating and managing **programmatic timers** using the `javax.ejb.TimerService` interface. It provides:
* Dynamic timer creation with custom durations
* Callback handling via `@Timeout`
* A lightweight REST interface to start and inspect timers
Primarily intended for educational purposes, this demo helps you understand how to integrate timer-based tasks into your enterprise beans.
---
## 📂 Source Structure
```
Programmatical-Timer-J2EE/
├── src/main/java/
│ └── com/tharindu/ee/timer
│ ├── ejb/
│ ├── TaskSessionBean.java
│ ├── TimerNewSessionBean.java
│ ├── TimerSessionBean.java
│ ├── servlet/
│ ├── Test.java
│ ├── TimerTest.java
│ ├── CancelTimer.java
└── src/main/resources/
└── META-INF/
```
> *Note:* Package names (`com.tharindu.ee.timer`) should reflect your own domain.
---
## 🛠️ Technologies & Dependencies
* **Java EE / Jakarta EE** (EJB, JAX-RS)
* **Maven** for build & dependency management
* **Application Server**: WildFly, GlassFish, or any JEE container with EJB support
* **JSON-B / Jackson** for JSON serialization
* **JUnit & Arquillian** (optional) for integration testing
---
## 🚀 Getting Started
### Prerequisites
* **JDK 11+**
* **Maven 3.6+**
* **Java EE–compliant server** (WildFly 21+, GlassFish 5+)
* **Git**
### Clone & Build
```bash
# Clone the repo
git clone https://github.com/Tharindu714/Programmatical-Timer-J2EE.git
cd Programmatical-Timer-J2EE
# Build with Maven
mvn clean package
```
### Deploy & Run
1. **Deploy** the generated WAR (`target/timer.war`) to your server’s `deployments/` folder.
2. **Start** (or restart) the server.
3. **Access** the REST API at `http://localhost:8080/timer-demo/api/timer`.
---
## 📚 Core Components
### TimerBean (EJB)
* **Injection:** `@Resource private TimerService timerService;`
* **Create Timer:** `timerService.createSingleActionTimer(duration, new TimerConfig(info, false));`
* **Timeout Callback:** Method annotated `@Timeout` handles expiration events.
### REST Interface
* **TimerResource.java:** Defines endpoints to:
* **POST** `/api/timer` → Create a new timer (JSON payload with `duration`).
* **GET** `/api/timer/{id}` → Retrieve timer info (status, next timeout).
---
## 📄 API Endpoints
| Method | Endpoint | Description |
| ------ | ----------------- | ------------------------------------------- |
| POST | `/api/timer` | Create a timer (body: `{"duration":60000}`) |
| GET | `/api/timer/{id}` | Get timer details and info |
---
## 🔄 Timer Workflow
1. **Client** sends POST with desired duration.
2. **TimerBean** uses `TimerService` to schedule a `SingleActionTimer`.
3. Upon expiration, the **@Timeout** method executes business logic (e.g., logging).
4. **Client** can query status via GET endpoint.
---
## 🛡️ Error Handling & Logging
* **Validation:** Check payload duration is positive; return `400 Bad Request` if invalid.
* **ExceptionMapper:** Converts exceptions into JSON error responses.
* **Logging:** Standard `java.util.logging` in `logging.properties`.
---
## 🤝 Contributing
We welcome improvements!
1. **Fork** the repository.
2. **Create a branch:** `git checkout -b feature/xyz`.
3. **Commit** your changes with clear messages.
4. **Open** a Pull Request against `main`.
Please ensure Java EE best practices and update this README if structure changes.
---
## 📜 License
MIT © 2025 Tharindu714
---
> Demonstrating enterprise timers, one callback at a time! ☕️✨