IOC with a Map for Resource Management

[John Borys]

Are there any real world examples (I have seen the documentation on this topic) that show a step by step approach to a newbie that wants to use injection with a Map using the Application context?

What I am trying to do is have the Application Context populate a Map that will be used to populate all drop downs in the presentation layer. The data is realtively static and I am thinking of it as a resource.

This post is related to another I made in the web forum on Refence Data Storage/Access. Although it was recommended that I use hibernate, we are thinking that we want a separation of concerns so that this will be treated as more of a service that might be placed on a different server than the Presentation.

[Colin Sampaleanu]

Can you define a bit better what you want above and beyond the normal capabilities of the 'map' element supported by the beanfactory/appcontext?

[John Borys]

I want a service to populate the Map. I just want to access the map from the Application context.

I was thinking of calling the service from a constructor and populating a property Map keyValueMap:

public class RefData {
	private ArrayList RefDatalist;
	private Map keyValueMap;
	public static Logger logger = Logger.getLogger(RefData.class);
	
	public RefData()	{
		RefDataService service = new RefDataService();
		try {
			keyValueMap = service.getRefDataMap();
		}
		catch (Throwable th) {
			logger.info("An Exception has been thrown.");
			logger.info(th.getMessage());
			throw new ApplicationRuntimeException	(th);			
		}
	}
}

I then want to store this map, built in the constructor, in the Application Context for the presentation layer to access.

The service builds the reference data dynamically so I am not sure that the Map element will work but maybe just constructor injection:

Here is how I build the Map:

public class GetRefDataService extends HibernateDaoSupport {
	private String key;
	private PersistSession persist;

	/**
	 * 
	 */
	public GetRefDataService(PersistSession persist) {
		setPersist(persist);
	}

	public Map buildKeyValueMap() throws Throwable	{
		RefData refData = new RefData();
		Map keyValueMap = new HashMap();	

		ArrayList keys = refData.returnCodeTypeList();

		for &#40;int i=0; i<keys.size&#40;&#41;;i++&#41;	&#123;
			String key = keys.get&#40;i&#41;.toString&#40;&#41;;
			Iterator value = getTextForCode&#40;key&#41;;
			keyValueMap.put&#40;key, value&#41;;
			
		&#125;
		return keyValueMap;
	&#125;
	
	public Map execute&#40;&#41; throws Throwable &#123;		
		Map refDataMap = buildKeyValueMap&#40;&#41;;
		return refDataMap;		
	&#125;
	
	private Iterator getTextForCode&#40;String key&#41; throws Throwable	&#123;
		List list = null;
		
		String refDataType = key;
				
//Replace "find" with findByNamedQuery here!**************************************************************
		list = persist.find&#40;"from REF_DATA in class ReferenceData where REF_DATA_TYPE = '"+ refDataType + "'"&#41;;		
		
		return list.iterator&#40;&#41;;
&#125;
	
//Accessors here	

&#125;

[irbouho]

John,
I do not understand what you are trying to achieve here but if you need to expose a result of a bean method call (that is of type Map) in the appcontext, you can do the following

  <bean id="values"
            class="org.springframework.beans.factory.config.MethodInvokingFactoryBean" singleton="true">
    <property name="targetObject">
      <ref bean="myRefDataService"/>
    </property>
    <property name="targetMethod">
     <value>getRefDataMap</value>
    </property>
  </bean>

HTH