net.lecousin.reactive.data.relational.LcReactiveDataRelationalInitializer Maven / Gradle / Ivy

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package net.lecousin.reactive.data.relational;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.yaml.snakeyaml.Yaml;

import net.lecousin.reactive.data.relational.enhance.ClassPathScanningEntities;
import net.lecousin.reactive.data.relational.enhance.Enhancer;

public class LcReactiveDataRelationalInitializer {

	private static final Log logger = LogFactory.getLog(LcReactiveDataRelationalInitializer.class);
	
	private static boolean initialized = false;
	
	public static class Config {
		private List entities = new LinkedList<>();

		public List getEntities() {
			return entities;
		}
	}
	
	private LcReactiveDataRelationalInitializer() {
		// no instance
	}
	
	public static void init() {
		if (initialized)
			return;
		initialized = true;
		logger.info("Initializing lc-reactive-data-relational");
		try {
			Config config = loadConfiguration();
			List entities = config.getEntities();
			if (entities.isEmpty()) {
				logger.info("No entities declared in lc-reactive-data-relational.yaml => scan class path");
				entities = new ArrayList<>(ClassPathScanningEntities.scan());
			}
			Enhancer.enhance(entities);
		} catch (Exception e) {
			logger.error("Error configuring lc-reactive-data-relational", e);
		}
	}
	
	public static Config loadConfiguration() throws IOException {
		Enumeration urls = LcReactiveDataRelationalInitializer.class.getClassLoader().getResources("lc-reactive-data-relational.yaml");
		Config config = new Config();
		while (urls.hasMoreElements()) {
			URL url = urls.nextElement();
			logger.info("Loading configuration from " + url);
			loadConfiguration(url, config);
		}
		return config;
	}
	
	private static void loadConfiguration(URL url, Config config) {
		try (InputStream input = url.openStream()) {
			Yaml yaml = new Yaml();
			Map root = yaml.load(input);
			if (root.containsKey("entities")) {
				configureEntities(config, "", root.get("entities"));
			}
		} catch (Exception e) {
			logger.error("Unable to read configuration file", e);
		}
	}
	
	@SuppressWarnings("rawtypes")
	private static void configureEntities(Config config, String prefix, Object value) {
		if (value instanceof String)
			config.entities.add(prefix + (String)value);
		else if (value instanceof Collection)
			for (Object element : (Collection)value)
				configureEntities(config, prefix, element);
		else if (value instanceof Map)
			for (Map.Entry entry : ((Map)value).entrySet())
				configureEntities(config, prefix + entry.getKey() + '.', entry.getValue());
		else
			logger.warn("Unexpected entity package value: " + value);
	}
	

}