SpringEtmMonitorContextSupport.java

/*
 *
 * Copyright (c) void.fm
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 * Redistribution and use in source and binary forms, with or without modification,
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 * used to endorse or promote products derived from this software without specific
 * prior written permission.
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package etm.contrib.integration.spring.web;

import etm.core.monitor.EtmMonitor;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;

import javax.servlet.ServletException;
import java.util.Iterator;
import java.util.Map;

/**
 * Helper class to retrieve EtmMonitor instance from etm.contrib.integration.spring configuration.
 *
 * @author void.fm
 * @version $Revision$
 */
public class SpringEtmMonitorContextSupport {

  public static final String ETM_MONITOR_PARAMETER_NAME = "etmMonitorName";

  public static EtmMonitor locateEtmMonitor(ApplicationContext ctx, String etmMonitorName) throws ServletException {
    if (etmMonitorName != null) {
      try {
        return (EtmMonitor) ctx.getBean(etmMonitorName);
      } catch (BeansException e) {
        throw new ServletException("Unable to locate EtmMonitor instance called '" + etmMonitorName + "'");         
      }
    } else {
      Map map = ctx.getBeansOfType(EtmMonitor.class);
      if (!map.isEmpty()) {
        if (map.size() == 1) {
          return (EtmMonitor) map.values().iterator().next();
        } else {
          StringBuffer beanNames = new StringBuffer();
          for (Iterator iterator = map.keySet().iterator(); iterator.hasNext();) {
            String beanName = (String) iterator.next();
            beanNames.append(beanName);
            beanNames.append(',');
          }
          beanNames.deleteCharAt(beanNames.length() - 1);
          throw new ServletException("Located more than one EtmMonitor instance. Please specify the name " +
            "of EtmMonitor instance. [Found: " + beanNames + "]");
        }
      } else {
        throw new ServletException("Unable to locate EtmMonitor instance in bean definitions.");
      }
    }
  }

}