javax.ejb.embeddable.EJBContainer Maven / Gradle / Ivy

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package javax.ejb.embeddable;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.ejb.EJBException;
import javax.ejb.spi.EJBContainerProvider;
import javax.naming.Context;

/**
 * Used to execute an EJB application in an embeddable container.
 * 
 * @author Carlo de Wolf
 * @version $Revision$
 * @since 3.1
 */
public abstract class EJBContainer implements AutoCloseable
{
   public static final String APP_NAME = "javax.ejb.embeddable.appName";
   public static final String MODULES = "javax.ejb.embeddable.modules";
   public static final String PROVIDER = "javax.ejb.embeddable.provider";
   
   private static final Pattern nonCommentPattern = Pattern.compile("^([^#]+)");

   private static List factories = new ArrayList();
   
   static
   {
      findAllFactories();
   }
   
   /**
    * Shutdown an embeddable EJBContainer instance.
    */
   @Override
   public abstract void close();
   
   /**
    * Create and initialize an embeddable EJB container. 
    * JVM classpath is searched for all ejb-jars or exploded ejb-jars in directory format.
    * 
    * @return EJBContainer instance
    * @throws EJBException Thrown if the container or application could not 
    *   be successfully initialized.
    */
   public static EJBContainer createEJBContainer() throws EJBException
   {
      return createEJBContainer(null);
   }
   
   /**
    * Create and initialize an embeddable EJB container with an 
    * set of configuration properties and names of modules to be initialized. 
    * 
    * @param properties One or more spec-defined or vendor-specific properties. 
    *   The spec reserves the prefix "javax.ejb." for spec-defined properties.
    * @return EJBContainer instance
    * @throws EJBException Thrown if the container or application could not 
    *   be successfully initialized.
    */
   public static EJBContainer createEJBContainer(Map properties)
      throws EJBException
   {
      for(EJBContainerProvider factory : factories)
      {
         EJBContainer container = factory.createEJBContainer(properties);
         if(container != null)
            return container;
      }
      throw new EJBException("Unable to instantiate container with factories " + factories);
   }
   
   private static List factoryNamesFromReader(BufferedReader reader) throws IOException
   {
      List names = new ArrayList();
      String line;
      while ((line = reader.readLine()) != null)
      {
         line = line.trim();
         Matcher m = nonCommentPattern.matcher(line);
         if (m.find())
         {
            names.add(m.group().trim());
         }
      }
      return names;
   }
   
   private static void findAllFactories()
   {
      try
      {
         ClassLoader loader = Thread.currentThread().getContextClassLoader();
         Enumeration resources = loader.getResources("META-INF/services/" + EJBContainerProvider.class.getName());
         Set names = new HashSet();
         while (resources.hasMoreElements())
         {
            URL url = resources.nextElement();
            InputStream is = url.openStream();
            try
            {
               names.addAll(factoryNamesFromReader(new BufferedReader(new InputStreamReader(is))));
            }
            finally
            {
               is.close();
            }
         }
         for (String s : names)
         {
            Class factoryClass = loader.loadClass(s);
            factories.add(EJBContainerProvider.class.cast(factoryClass.newInstance()));
         }
      }
      catch (IOException e)
      {
         throw new EJBException(e);
      }
      catch (InstantiationException e)
      {
         throw new EJBException(e);
      }
      catch (IllegalAccessException e)
      {
         throw new EJBException(e);
      }
      catch (ClassNotFoundException e)
      {
         throw new EJBException(e);
      }
   }
   
   /**
    * Retrieve a naming context for looking up references to session beans executing in
    * the embeddable container.
    * 
    * @return The naming context.
    */
   public abstract Context getContext();
}