servicelocator.java

一个非常好的FRAMWRK!是一个外国组织做的!不!

package com.jdon.servicelocator.ejb;


import java.net.URL;

import javax.ejb.EJBHome;
import javax.ejb.EJBLocalHome;
import javax.jms.QueueConnectionFactory;
import javax.jms.Queue;
import javax.jms.TopicConnectionFactory;
import javax.jms.Topic;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.rmi.PortableRemoteObject;
import javax.sql.DataSource;

import com.jdon.servicelocator.ServiceLocatorException;
import org.apache.log4j.Logger;
/**
 *  This class is an implementation of the Service Locator pattern. It is
 *  used to looukup resources such as EJBHomes, JMS Destinations, etc.
 */
public class ServiceLocator implements java.io.Serializable {
  private final static Logger logger = Logger.getLogger(ServiceLocator.class);
  private InitialContext ic;

  private static ServiceLocator me;

  public ServiceLocator() throws ServiceLocatorException {
    try {
      ic = new InitialContext();
    } catch (NamingException ne) {
      throw new ServiceLocatorException(ne);
    } catch (Exception e) {
      throw new ServiceLocatorException(e);
    }
  }

  /**
   * will get the ejb Local home factory.
   * clients need to cast to the type of EJBHome they desire
   *
   * @return the Local EJB Home corresponding to the homeName
   */
  public EJBLocalHome getLocalHome(String jndiHomeName) throws
      ServiceLocatorException {
    EJBLocalHome home = null;
    try {
      home = (EJBLocalHome) ic.lookup(jndiHomeName);
    } catch (NamingException ne) {
      throw new ServiceLocatorException(ne);
    } catch (Exception e) {
      throw new ServiceLocatorException(e);
    }
    return home;
  }

  /**
   * will get the ejb Remote home factory.
   * clients need to cast to the type of EJBHome they desire
   *
   * @return the EJB Home corresponding to the homeName
   */
  public EJBHome getRemoteHome(String jndiHomeName, Class className) throws
      ServiceLocatorException {
    EJBHome home = null;
    try {
      Object objref = ic.lookup(jndiHomeName);
      Object obj = PortableRemoteObject.narrow(objref, className);
      home = (EJBHome) obj;
    } catch (NamingException ne) {
      throw new ServiceLocatorException(ne);
    } catch (Exception e) {
      throw new ServiceLocatorException(e);
    }
    return home;
  }

  /**
   * @return the factory for the factory to get queue connections from
   */
  public QueueConnectionFactory getQueueConnectionFactory(String
      qConnFactoryName) throws ServiceLocatorException {
    QueueConnectionFactory factory = null;
    try {
      factory = (QueueConnectionFactory) ic.lookup(qConnFactoryName);
    } catch (NamingException ne) {
      throw new ServiceLocatorException(ne);
    } catch (Exception e) {
      throw new ServiceLocatorException(e);
    }
    return factory;
  }

  /**
   * @return the Queue Destination to send messages to
   */
  public Queue getQueue(String queueName) throws ServiceLocatorException {
    Queue queue = null;
    try {
      queue = (Queue) ic.lookup(queueName);
    } catch (NamingException ne) {
      throw new ServiceLocatorException(ne);
    } catch (Exception e) {
      throw new ServiceLocatorException(e);
    }
    return queue;
  }

  /**
   * This method helps in obtaining the topic factory
   * @return the factory for the factory to get topic connections from
   */
  public TopicConnectionFactory getTopicConnectionFactory(String
      topicConnFactoryName) throws ServiceLocatorException {
    TopicConnectionFactory factory = null;
    try {
      factory = (TopicConnectionFactory) ic.lookup(topicConnFactoryName);
    } catch (NamingException ne) {
      throw new ServiceLocatorException(ne);
    } catch (Exception e) {
      throw new ServiceLocatorException(e);
    }
    return factory;
  }

  /**
   * This method obtains the topc itself for a caller
   * @return the Topic Destination to send messages to
   */
  public Topic getTopic(String topicName) throws ServiceLocatorException {
    Topic topic = null;
    try {
      topic = (Topic) ic.lookup(topicName);
    } catch (NamingException ne) {
      throw new ServiceLocatorException(ne);
    } catch (Exception e) {
      throw new ServiceLocatorException(e);
    }
    return topic;
  }

  /**
   * This method obtains the datasource itself for a caller
   * @return the DataSource corresponding to the name parameter
   */
  public DataSource getDataSource(String dataSourceName) throws
      ServiceLocatorException {
    DataSource dataSource = null;
    try {
      dataSource = (DataSource) ic.lookup(dataSourceName);
    } catch (NamingException ne) {
      throw new ServiceLocatorException(ne);
    } catch (Exception e) {
      throw new ServiceLocatorException(e);
    }
    return dataSource;
  }

  /**
   * @return the URL value corresponding
   * to the env entry name.
   */
  public URL getUrl(String envName) throws ServiceLocatorException {
    URL url = null;
    try {
      url = (URL) ic.lookup(envName);
    } catch (NamingException ne) {
      throw new ServiceLocatorException(ne);
    } catch (Exception e) {
      throw new ServiceLocatorException(e);
    }

    return url;
  }

  /**
   * @return the boolean value corresponding
   * to the env entry such as SEND_CONFIRMATION_MAIL property.
   */
  public boolean getBoolean(String envName) throws ServiceLocatorException {
    Boolean bool = null;
    try {
      bool = (Boolean) ic.lookup(envName);
    } catch (NamingException ne) {
      throw new ServiceLocatorException(ne);
    } catch (Exception e) {
      throw new ServiceLocatorException(e);
    }
    return bool.booleanValue();
  }

  /**
   * @return the String value corresponding
   * to the env entry name.
   */
  public String getString(String envName) throws ServiceLocatorException {
    String envEntry = null;
    try {
      envEntry = (String) ic.lookup(envName);
    } catch (NamingException ne) {
      throw new ServiceLocatorException(ne);
    } catch (Exception e) {
      throw new ServiceLocatorException(e);
    }
    return envEntry;
  }

  public Object getDAO(String jndiDAOName) throws ServiceLocatorException {

    Object object = null;
    try {
      String className = (String) ic.lookup(jndiDAOName);
      ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
      object = classLoader.loadClass(className).newInstance();
    } catch (NamingException ne) {
      throw new ServiceLocatorException(ne);
    } catch (Exception se) {
      throw new ServiceLocatorException(se);
    }
    return object;
  }

}