Initialising static property of class through injection on startup

[rookie]

Hi all,i am new to spring.Recently we have started using spring in the project.
Below is my code that i am using

public class DSManager {
  private static DataSource dataSource = null;   
  public static void setDataSource(DataSource dataSource) {
    DSManager.dataSource = dataSource;
  }
  public DataSourceManager() {

  }

   public static DataSource getDataSource() {
    return  dataSource ;}

And this is the construct from my applicationContext.xml


<bean id="dataSource" class="org.springframework.jndi.JndiObjectFactoryB ean">
<property name="jndiName">
<value>java:comp/env/jdbc/abc</value>
</property>
</bean>

<bean id="initialiseDataSource" class="com.abc.DSManager " >
<property name="dataSource">
<ref local="dataSource"/>
</property>
</bean>

I have one requirement.First i want to initialise the static datasource property at the start of the application.Whenever i try to run this application
i get this Exception

org.springframework.beans.factory.BeanCreationExce ption: Error creating bean with name 'initialiseDataSource' defined in URL classes/springApplicationContext.xml]: Error setting property values; nested exception is org.springframework.beans.NotWritablePropertyExcep tion: Invalid property 'dataSource' of bean class :
Bean property 'dataSource' is not writable or has an invalid setter method: Does the parameter type of the setter match the return type of the getter?
org.springframework.beans.NotWritablePropertyExcep tion: Invalid property 'dataSource' of bean class :
Bean property 'dataSource' is not writable or has an invalid setter method: Does the parameter type of the setter match the return type of the getter?
at org.springframework.beans.BeanWrapperImpl.setPrope rtyValue(BeanWrapperImpl.java:670)
at org.springframework.beans.BeanWrapperImpl.setPrope rtyValue(BeanWrapperImpl.java:572)
at org.springframework.beans.BeanWrapperImpl.setPrope rtyValue(BeanWrapperImpl.java:737)
at org.springframework.beans.BeanWrapperImpl.setPrope rtyValues(BeanWrapperImpl.java:764)
at org.springframework.beans.BeanWrapperImpl.setPrope rtyValues(BeanWrapperImpl.java:753)
at org.springframework.beans.factory.support.Abstract AutowireCapableBeanFactory.applyPropertyValues(Abs tractAutowireCapableBeanFactory.java:1057)
at org.springframework.beans.factory.support.Abstract AutowireCapableBeanFactory.populateBean(AbstractAu towireCapableBeanFactory.java:857)
at org.springframework.beans.factory.support.Abstract AutowireCapableBeanFactory.createBean(AbstractAuto wireCapableBeanFactory.java:378)
at org.springframework.beans.factory.support.Abstract BeanFactory.getBean(AbstractBeanFactory.java:233)
at org.springframework.beans.factory.support.Abstract BeanFactory.getBean(AbstractBeanFactory.java:145)
at org.springframework.beans.factory.support.DefaultL istableBeanFactory.preInstantiateSingletons(Defaul tListableBeanFactory.java:283)
at org.springframework.context.support.AbstractApplic ationContext.refresh(AbstractApplicationContext.ja va:313)
at org.springframework.web.context.support.AbstractRe freshableWebApplicationContext.refresh(AbstractRef reshableWebApplicationContext.java:139)
at org.springframework.web.context.ContextLoader.crea teWebApplicationContext(ContextLoader.java:246)
at org.springframework.web.context.ContextLoader.init WebApplicationContext(ContextLoader.java:184)
at org.springframework.web.context.ContextLoaderServl et.init(ContextLoaderServlet.java:83)
at javax.servlet.GenericServlet.init(GenericServlet.j ava:211)
at org.apache.catalina.core.StandardWrapper.loadServl et(StandardWrapper.java:1091)
at org.apache.catalina.core.StandardWrapper.load(Stan dardWrapper.java:925)
at org.apache.catalina.core.StandardContext.loadOnSta rtup(StandardContext.java:3857)
at org.apache.catalina.core.StandardContext.start(Sta ndardContext.java:4118)
at org.apache.catalina.core.ContainerBase.addChildInt ernal(ContainerBase.java:759)
at org.apache.catalina.core.ContainerBase.addChild(Co ntainerBase.java:739)
at org.apache.catalina.core.StandardHost.addChild(Sta ndardHost.java:524)
at org.apache.catalina.startup.HostConfig.deployDescr iptor(HostConfig.java:589)
at org.apache.catalina.startup.HostConfig.deployDescr iptors(HostConfig.java:536)
at org.apache.catalina.startup.HostConfig.deployApps( HostConfig.java:471)
at org.apache.catalina.startup.HostConfig.start(HostC onfig.java:1102)
at org.apache.catalina.startup.HostConfig.lifecycleEv ent(HostConfig.java:311)
at org.apache.catalina.util.LifecycleSupport.fireLife cycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.ContainerBase.start(Conta inerBase.java:1020)
at org.apache.catalina.core.StandardHost.start(Standa rdHost.java:718)
at org.apache.catalina.core.ContainerBase.start(Conta inerBase.java:1012)
at org.apache.catalina.core.StandardEngine.start(Stan dardEngine.java:442)
at org.apache.catalina.core.StandardService.start(Sta ndardService.java:450)
at org.apache.catalina.core.StandardServer.start(Stan dardServer.java:683)
at org.apache.catalina.startup.Catalina.start(Catalin a.java:537)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Native MethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(De legatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.apache.catalina.startup.Bootstrap.start(Bootst rap.java:271)
at org.apache.catalina.startup.Bootstrap.main(Bootstr ap.java:409)

[baronludwig]

Maybe worth reviewing comments on the following JIRA relating to the injection of statics through Spring.
http://opensource.atlassian.com/proj...rowse/SPR-3845

[Paul Newport]

A couple of questions:

Why are you using a datasource in one of your own classes DSManager ? The Spring framework provides you with classes like JdbcDaoSupport and HibernateDaoSupport into which you inject datasources. I've never had to do anything with a datasource in one of my own classes.

If you do need to have your own DSManager why do you need to statically initialize the datasource ? What is wrong with a pojo DSManager that you inject the datasource into ?

[d2dmono]

Well, may be this option is not quite right in srping terms but, this work for me, and at last i have got only one instance in my context.

Set static properties in a static factory method.

i mean set in appContext.xml as follows

<bean id="properties"
		class="org.springframework.beans.factory.config.PropertiesFactoryBean">
		<property name="location"
			value="classpath:/a/property/file/Utils.properties" />
	</bean>

	<bean class="your.class.UtilMessages" factory-method="setInstance" autowire="autodetect" scope="singleton">
	 	<constructor-arg ref="properties" />
	</bean>

The interest thing is in factory method and the argument.

So the class looks like...

public class UtilMessages {

	public static Properties properties;
		
	// Cheating spring to set a static property.
	public static Properties setInstance(Properties propertiesArgs) {
		properties = propertiesArgs;
		return properties;
	}

	public static String getMsg(String key) {
		return properties.getProperty(key);
	}
}

I did call it "setInstance" because i'm setting the value, even when it's a cosntructor.

So you can set any static property in context instantantion and use them after as any static value.

For me was a property file, so i can read it by calling static UtilsMessages.getMsg("key") method. No need to set dependency in xml file and no need to create a new instance each time i need it.

Regadrs.

[arakhshan]

I found similar thread here but I haven't seen a clear response so I figured to post my question specifically.

Assume you have a factory class that it requires other objects to be injected to utilize its static methods.

public class TestUtilFactory{
	private static IAddressDao addressDao;
	
	private static IUserDao userDao;
	
	public static Address createAddress(){
// do some magic here utilizing the static instances addressDao
	}

the addressDao & userDao are already managed by container and available to be injected but none of@Autowired, @Resource nor the static-factory injection works.

Any suggestion would be greatly appreciated.

Thank,
Arash