Capture Java Main Class Output in Spring Boot and Display in Angular

I have a Java Main class in a Spring Boot project that generates output when run. It needs to work both independently via the CLI and through a Spring Boot controller. When I input values via a form on the frontend, I want to run the Main class with those inputs, capture its output, and display it in real-time in a logs container on the Angular frontend.

Here are the Angular component's HTML and TypeScript files, along with the Java Main class and the Spring Boot controller.

Frontend(Angular)

admin-dashboard.component.html

<div class="dashboard-header"></div>

<div class="dashboard">
<div class="form-container">
<h2>Enter Values</h2>
<form (ngSubmit)="submitForm()">
<label for="totalTickets">Total Tickets:</label>
<input type="number" id="totalTickets" [(ngModel)]="totalTickets" name="totalTickets" required>

<label for="ticketReleaseRate">Ticket Release Rate:</label>
<input type="number" id="ticketReleaseRate" [(ngModel)]="ticketReleaseRate" name="ticketReleaseRate" required>

<label for="customerRetrievalRate">Customer Retrieval Rate:</label>
<input type="number" id="customerRetrievalRate" [(ngModel)]="customerRetrievalRate" name="customerRetrievalRate" required>

<label for="maxTicketCapacity">Maximum Ticket Capacity:</label>
<input type="number" id="maxTicketCapacity" [(ngModel)]="maxTicketCapacity" name="maxTicketCapacity" required>

<button type="submit">Start</button>
<button type="button" (click)="stop()">Stop</button>
</form>
</div>

<div class="logs-container">
<h2>Logs</h2>
<div class="logs">
<div *ngFor="let log of logs">{{ log }}</div>
</div>
</div>
</div>


admin-dashboard.component.ts

import { Component, OnInit } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Component({
selector: 'app-admin-dashboard',
templateUrl: './admin-dashboard.component.html',
styleUrls: ['./admin-dashboard.component.scss']
})
export class AdminDashboardComponent implements OnInit {
totalTickets: number = 500;
ticketReleaseRate: number = 123;
customerRetrievalRate: number = 43;
maxTicketCapacity: number = 2;

// For storing logs
logs: string[] = [];

constructor(private http: HttpClient) { }

ngOnInit(): void {
this.http.get<any>('http://localhost:8080/api/ticketing/config')
.subscribe(response => {
this.totalTickets = response.totalTickets || 500;
this.ticketReleaseRate = response.ticketReleaseRate || 123;
this.customerRetrievalRate = response.customerRetrievalRate || 43;
this.maxTicketCapacity = response.maxTicketCapacity || 2;
});
}

// For submitting the form data to the backend
submitForm(): void {
const formData = {
totalTickets: this.totalTickets,
ticketReleaseRate: this.ticketReleaseRate,
customerRetrievalRate: this.customerRetrievalRate,
maxTicketCapacity: this.maxTicketCapacity
};

this.http.post('http://localhost:8080/api/ticketing/config', formData)
.subscribe(response => {
this.logs.push('Configuration updated successfully!');
console.log('Form Submitted:', response);
}, error => {
this.logs.push('Error updating configuration');
console.error('Error:', error);
});
}

// For stopping the process
stop(): void {
console.log('Booking process stopped');
this.logs.push('Booking process stopped');
}
}


Java (needs to run separately in the CLI while also having its output displayed on the frontend)

Main class

package com.oop.Springboot.ticketingcli;

public class Main {

public static void runTicketingProcess(Configuration config) {
int totalTickets = config.getTotalTickets();
int ticketReleaseRate = config.getTicketReleaseRate();
int customerRetrievalRate = config.getCustomerRetrievalRate();
int maxCapacity = config.getMaxTicketCapacity();

TicketPool ticketPool = new TicketPool(maxCapacity);

// Create vendor threads to add tickets to the pool
for (int i = 0; i < ticketReleaseRate; i++) {
int vendorId = i + 1;
Vendor vendor = new Vendor(vendorId, ticketPool, totalTickets, ticketReleaseRate);
Thread vendorThread = new Thread(vendor);
vendorThread.start();
}

// Create customer threads to book tickets from the pool
for (int i = 0; i < customerRetrievalRate; i++) {
int customerId = i + 1;
Customer customer = new Customer(customerId, ticketPool, 1000);
Thread customerThread = new Thread(customer);
customerThread.start();
}
}

// Main method for running the application as a standalone Java app
public static void main(String[] args) {
// Create a sample configuration for testing
Configuration config = new Configuration();
config.setTotalTickets(100);
config.setTicketReleaseRate(10);
config.setCustomerRetrievalRate(5);
config.setMaxTicketCapacity(50);

// Run the ticketing process with the sample configuration
runTicketingProcess(config);
}
}



Controller class

package com.oop.Springboot.controller;

import com.oop.Springboot.ticketingcli.Configuration;
import com.oop.Springboot.ticketingcli.Main;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api/ticketing")
@CrossOrigin(origins = "http://localhost:4200" , allowedHeaders = "*")
public class TicketingController {

private Configuration config;

public TicketingController() {
this.config = new Configuration();
}

@PostMapping("/config")
public String updateConfig(@RequestBody Configuration newConfig) {
this.config.setTotalTickets(newConfig.getTotalTickets());
this.config.setTicketReleaseRate(newConfig.getTicketReleaseRate());
this.config.setCustomerRetrievalRate(newConfig.getCustomerRetrievalRate());
this.config.setMaxTicketCapacity(newConfig.getMaxTicketCapacity());

Main.runTicketingProcess(config);
return "Configuration updated successfully!";
}

@GetMapping("/config")
public Configuration getConfig() {
return this.config;
}
}


What should I add to make this work?

I tried integrating a Java Main class in a Spring Boot project to produce real-time output and send it to an Angular frontend. The goal was to input values through a form and display the output in a logs container in real-time.

However, I am encountering the following issues:

Error in Logs Container: When the "Start" button is clicked, the logs container displays the message:

"Error updating configuration".


Console Error: I’m getting the following error in the browser's console:

{
"headers": {
"normalizedNames": {},
"lazyUpdate": null
},
"status": 403,
"statusText": "OK",
"url": "http://localhost:8080/api/ticketing/config",
"ok": false,
"name": "HttpErrorResponse",
"message": "Http failure response for http://localhost:8080/api/ticketing/config: 403 OK",
"error": null
}


do I need to use database?

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