java-code-style

name	java-code-style
description	Java 25 code style conventions for crypto-scout-test including naming, imports, error handling, and testing patterns Use when this capability is needed.
metadata	{"author":"akarazhev"}

What I Do

Enforce consistent code style across the crypto-scout-test library following established Java 25 conventions.

File Structure

1-23:   MIT License header
25:     Package declaration
26:     Blank line
27+:    Imports (java.* → third-party → static, blank lines between groups)
        Blank line
        Class/enum/interface declaration

Import Organization

import java.io.IOException;
import java.nio.file.Path;
import java.time.Duration;

import com.rabbitmq.stream.Environment;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import static com.github.akarazhev.cryptoscout.test.Constants.DB.JDBC_URL;
import static org.junit.jupiter.api.Assertions.assertEquals;

Naming Conventions

Element	Convention	Example
Classes	PascalCase	StreamTestPublisher, MockData, AmqpTestConsumer
Methods	camelCase with verb	waitForDatabaseReady, deleteFromTables, canConnect
Constants	UPPER_SNAKE_CASE	JDBC_URL, DB_USER, BYBIT_STREAM
Parameters/locals	final var	final var timeout, final var data
Test classes	<ClassName>Test	MockBybitSpotDataTest, StreamConsumerPublisherTest
Test methods	should<Subject><Action>	shouldSpotKline1DataReturnMap, shouldPublishPayloadToStream

Access Modifiers

Utility Classes

final class Constants {
    private Constants() {
        throw new UnsupportedOperationException();
    }
    
    static final String PATH_SEPARATOR = "/";
    
    final static class DB {
        private DB() {
            throw new UnsupportedOperationException();
        }
        
        static final String JDBC_URL = System.getProperty("test.db.jdbc.url", "...");
    }
}

Factory Pattern

public final class StreamTestPublisher extends AbstractReactive implements ReactiveService {
    private final Executor executor;
    private final Environment environment;
    private final String stream;
    private final AtomicReference<Producer> producerRef = new AtomicReference<>();
    
    public static StreamTestPublisher create(final NioReactor reactor, final Executor executor,
                                             final Environment environment, final String stream) {
        return new StreamTestPublisher(reactor, executor, environment, stream);
    }
    
    private StreamTestPublisher(final NioReactor reactor, final Executor executor,
                                final Environment environment, final String stream) {
        super(reactor);
        this.executor = executor;
        this.environment = environment;
        this.stream = stream;
    }
}

Error Handling

// Unchecked exceptions for invalid state
if (is == null) {
    throw new IllegalStateException("Resource not found: " + path);
}

// Try-with-resources for all closeable resources
try (final var conn = DriverManager.getConnection(JDBC_URL, DB_USER, DB_PASSWORD);
     final var st = conn.createStatement();
     final var rs = st.executeQuery(SELECT_ONE)) {
    return rs.next();
} catch (final SQLException e) {
    return false;
}

// Interrupt handling
try {
    Thread.sleep(duration.toMillis());
} catch (final InterruptedException e) {
    Thread.currentThread().interrupt();
}

// Exception chaining
throw new IllegalStateException("Failed to resolve compose file URI", e);

Logging

private static final Logger LOGGER = LoggerFactory.getLogger(ClassName.class);

LOGGER.info("Connected to DB: {}", conn.getClientInfo());
LOGGER.warn("Error closing stream producer", ex);
LOGGER.error("Failed to start StreamTestPublisher", ex);

Testing (JUnit 6/Jupiter)

final class MockBybitSpotDataTest {
    
    @BeforeAll
    static void setUp() {
        PodmanCompose.up();
    }
    
    @AfterAll
    static void tearDown() {
        PodmanCompose.down();
    }
    
    @Test
    void shouldSpotKline1DataReturnMap() throws Exception {
        final var data = MockData.get(MockData.Source.BYBIT_SPOT, MockData.Type.KLINE_1);
        assertNotNull(data);
        assertFalse(data.isEmpty());
    }
}

Configuration Pattern

static final String VALUE = System.getProperty("property.key", "defaultValue");
static final int PORT = Integer.parseInt(System.getProperty("port.key", "5552"));
static final Duration TIMEOUT = Duration.ofMinutes(Long.getLong("timeout.key", 3L));

Key Project Classes

Class	Package	Purpose
MockData	com.github.akarazhev.cryptoscout.test	Typed mock data loader with Source/Type enums
PodmanCompose	com.github.akarazhev.cryptoscout.test	Container lifecycle management
DBUtils	com.github.akarazhev.cryptoscout.test	Database utilities
StreamTestPublisher	com.github.akarazhev.cryptoscout.test	RabbitMQ Streams publisher
StreamTestConsumer	com.github.akarazhev.cryptoscout.test	RabbitMQ Streams consumer
AmqpTestPublisher	com.github.akarazhev.cryptoscout.test	AMQP publisher
AmqpTestConsumer	com.github.akarazhev.cryptoscout.test	AMQP consumer
Assertions	com.github.akarazhev.cryptoscout.test	Test assertions

When to Use Me

Use this skill when:

• Writing new Java classes or methods
• Reviewing code for style compliance
• Understanding project conventions
• Organizing imports and file structure
• Implementing error handling patterns

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