package net.avcompris.commons3.web;
   
   import static com.google.common.base.Preconditions.checkNotNull;
   import static org.apache.commons.lang3.StringUtils.repeat;
   
   import java.io.PrintStream;
   import java.util.Map;
   import java.util.TreeMap;
   
  import javax.annotation.Nullable;
  
  import org.springframework.context.ApplicationContext;
  
  public abstract class ApplicationUtils {
  
  	/**
  	 * Dump the list of custom beans created for the application.
  	 *
  	 * @param packagePrefixes e.g. "net.avcompris.commons3.examples.users" (without
  	 *                      the trailing ".")
  	 */
  	public static void dumpBeans(final ApplicationContext context, final PrintStream ps,
  			final String... packagePrefixes) {
  
  		checkNotNull(context, "context");
  		checkNotNull(ps, "ps");
  		checkNotNull(packagePrefixes, "packagePrefixes");
  
  		System.out.println("Beans:");
  
  		final Map<String, String> beanNames = new TreeMap<>();
  
  		int beanClassNameMaxLength = 0;
  
  		for (final String beanName : context.getBeanDefinitionNames()) {
  
  			final Object bean = context.getBean(beanName);
  			final Class<?> beanClass = bean.getClass();
  
  			final Package beanPackage = beanClass.getPackage();
  
  			if (!containsPackagePrefix(packagePrefixes, beanPackage)) {
  				continue;
  			}
  
  			final String beanClassName = beanClass.getName();
  
  			beanNames.put(beanClassName, beanName);
  
  			beanClassNameMaxLength = Math.max(beanClassNameMaxLength, beanClassName.length());
  		}
  
  		for (final String beanClassName : beanNames.keySet()) {
  
  			final String beanName = beanNames.get(beanClassName);
  
  			System.out.println("  - " + beanClassName
  
  					+ repeat(' ', beanClassNameMaxLength - beanClassName.length() + 1)
  
  					+ "(" + beanName + ")");
  		}
  	}
  
  	private static boolean containsPackagePrefix(final String[] packagePrefixes, @Nullable final Package beanPackage) {
  
  		if (beanPackage == null) {
  			return false;
  		}
  
  		for (final String packagePrefix : packagePrefixes) {
  
  			if (beanPackage.getName().startsWith(packagePrefix + ".")) {
  
  				return true;
  			}
  		}
  
  		return false;
  	}
  }