package at.gv.egovernment.moa.id.proxy;

import java.util.HashMap;
import java.util.Map;

import at.gv.egovernment.moa.id.config.ConfigurationException;
import at.gv.egovernment.moa.id.config.proxy.OAProxyParameter;
import at.gv.egovernment.moa.id.config.proxy.ProxyConfigurationProvider;

/**
 * Factory delivering a {@link ConnectionBuilder} implementation for
 * an online application, initialized from configuration data. 
 * @author Paul Ivancsics
 * @version $Id$
 */
public class ConnectionBuilderFactory {

  /** default connection builder to be used for online application
   *  where no special implementation of the <code>ConnectionBuilder</code> 
   *  interface is configured 
   */
  private static ConnectionBuilder defaultConnectionBuilder;
  /** mapping from online application public URL prefix to an implementation
   *  of the <code>ConnectionBuilder</code> interface to be used;
   *  if no mapping is given for an online application, the 
   *  <code>DefaultConnectionBuilder</code> will be used */
  private static Map connectionBuilderMap;

  /**
   * Initializes the <code>ConnectionBuilder</code> map from the configuration data.
   * @throws ConfigurationException when the configuration cannot be read,
   *          or when a class name configured cannot be instantiated
   */
  public static void initialize() throws ConfigurationException {
    defaultConnectionBuilder = new DefaultConnectionBuilder();
    connectionBuilderMap = new HashMap();
    ProxyConfigurationProvider proxyConf = ProxyConfigurationProvider.getInstance();
    for (int i = 0; i < proxyConf.getOnlineApplicationParameters().length; i++) {
      OAProxyParameter oaParam = proxyConf.getOnlineApplicationParameters()[i];
      String publicURLPrefix = oaParam.getPublicURLPrefix();
      String className = oaParam.getConnectionBuilderImpl();
      if (className != null) {
        try {
          ConnectionBuilder cb = (ConnectionBuilder)Class.forName(className).newInstance();
          connectionBuilderMap.put(publicURLPrefix, cb); 
        }
        catch (Throwable ex) {
          throw new ConfigurationException("config.07", new Object[] {publicURLPrefix}, ex);
        }
      }
    }
  }
  
  /**
   * Gets the <code>ConnectionBuilder</code> implementation to be used for the given
   * online application.
   * @param publicURLPrefix public URL prefix of the online application
   * @return <code>ConnectionBuilder</code> implementation
   */
  public static ConnectionBuilder getConnectionBuilder(String publicURLPrefix) {
    ConnectionBuilder cb = (ConnectionBuilder) connectionBuilderMap.get(publicURLPrefix);
    if (cb == null)
      return defaultConnectionBuilder;
    else
      return cb;
  }

}