In an applicationcontext.xml, is it possible to set a value which can be used later in SPEL expressions?
For example is there a way to do this?:
<setProperty name="foo" value="someval" />
<bean id="beanId" name="beanName" class="SomeClass">
<property name="someVal" value="blah_${foo}"/>
</bean>
The actual reason I want to do this is that I use statements to create entity managers which are used in many different application contexts. The problem is that the entity managers require a unique name which is used by Bitronix to create a local file which breaks if multiple unit tests run at the same time using the same name for that field. To set that unique name I currently have a separate properties file for each application context and import it to get a unique name from it.
Rather than doing that nonsense I'd rather just do this:
<setProperty name="uniqueName" value="someUniqueName" />
<import resource="classpath*:shared/db/fooDb.xml" />
You can do this using Spring-el and util namespace:
<util:properties id="myprops">
<prop key="foo">someval</prop>
</util:properties>
<bean id="beanId" name="beanName" class="SomeClass">
<property name="someVal" value="blah_#{myprops.foo}"/>
</bean>
Related
I've been using org.springframework.beans.factory.config.PropertyPlaceholderConfigurer and in my experience ("citation needed" LOL) it sets the property values globally.
Is there a way to specify different PropertyPlaceholderConfigurer instances for different beans within the same application context xml?
My current code is similar to
<bean id="a" class="X">
<property name="foo" value="bar"/>
<property name="many" value="more"/>
</bean>
<bean id="b" class="X">
<property name="foo" value="baz"/>
<property name="number_of_properties" value="a zillion"/>
</bean>
I would like to do something like (pseudo-code below):
<bean id="a" class="X">
... parse the contents of "a.properties" here ...
</bean>
<bean id="b" class="X">
... parse the contents of "b.properties" here ...
</bean>
The above is non-working pseudo code to illustrate the concept; the point being, I want a different properties file to feed each bean.
WHY?
I want to have those specific properties in separate properties file and not in XML.
I think the following link can br helpful to you.
Reference Link
where #Value("${my.property.name}") annotation is used to bind the property file to a variable of type Properties which will reside in your bean class where you intend to use that properties file.
and you can define multiplte proprtiesplaceholder as below:
<bean id="myProperties"
class="org.springframework.beans.factory.config.PropertiesFactoryBean">
<property name="locations">
<list>
<value>classpath*:my.properties</value>
</list>
</property>
</bean>
and use the id as reference in your bean variable to initialize properties file to the bean.
And it will be handy to include with placeholder bean.
Kindly refer Importance of Unresolvable Placeholder link for detailed info regarding its usage.
Hope this was helpful.
I am implementing a module with Spring Cache mechanism. The module is generic and can cache different type of entities. So I don't want to change the Java code and want the user to configure the applicationcontext.xml file accordingly. He can put the name of the different types of entities within the applicationcontext.xml and the code should work. For e.g. -
<context:annotation-config/>
<cache:annotation-driven cache-manager="cacheManager"/>
<context:component-scan base-package="com.nokia.oss.sure.adapter"/>
<bean id="NetworkEntityService" class="com.nokia.oss.sure.adapter.cache.NetworkEntityServiceImpl"/>
<bean id="cacheManager" class="org.springframework.cache.support.SimpleCacheManager">
<property name="caches">
<set>
<bean class="org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean" name="NetworkEntity"/>
</set>
</property>
</bean>
He may change NetworkEntity to ServiceEntity and so on.
So in the Java code I need to mention -
#CacheConfig(cacheNames={"NetworkEntity"})
Or I can put the same for every method -
#CachePut(cacheNames="NetworkEntity", key="#entity.sureName")
public Entity addEntity(Entity entity) {
return entity;
}
But as I stated earlier, I don't want to put the cache name "NetworkEntity" in the Java code, but want to put the same in the applicationcontext.xml file. Is it possible?
Furthermore is it possible to omit all the annotations in the Java file? If I just use AbstractApplicationContext context = new GenericXmlApplicationContext("applicationContext.xml"); is it possible to mention in the applicationContext.xml file what are the methods where I want to apply the #Cacheable annotation for e.g.
I searched a lot, couldn't find it anywhere.
Thanks
Nirmalya
I found out the answer. We can put the following in the applicationContext.xml -
<!-- define caching behavior -->
<cache:advice id="cacheAdviceInterface" cache-manager="cacheManager">
<cache:caching cache="NetworkEntity">
<cache:cacheable method="getEntity"/>
<cache:cache-put method="putEntity"/>
</cache:caching>
</cache:advice>
In that case we don't need to put the #CacheConfig, #CachePut etc annotations within the Java file.
i have this definition for calling an EJB
<util:properties id="ejbJndiConfig" location="file:/path/to/ejb-jndi-config.properties" />
<jee:remote-slsb id="myEjbService"
jndi-name="myEjbName"
business-interface="foo.bar.MyBusinessInterface"
cache-home="false"
lookup-home-on-startup="false"
refresh-home-on-connect-failure="true"
environment-ref="ejbJndiConfig"
expose-access-context="true">
</jee:remote-slsb>
All is working great and an instance of:
org.springframework.ejb.access.SimpleRemoteStatelessSessionProxyFactoryBean is created to call the EJB method. But what about if i want to change this default behaviour and change the used class?
With old style spring we can do something like this:
<bean id="service" class="org.springframework.remoting.rmi.RmiProxyFactoryBean">
<property name="remoteInvocationFactory" ref="invocationFactory"/>
....
</bean>
<bean id="invocationFactory" class="src.rmi.CustomRemoteInvocationFactory"/>
is possible with new definition style?
I am new to spring. When i am going through auto wiring byType i came to know about these attributes primary and autowire-candidate.
I didn't get the exact difference b/w these two as setting these parameter to false will make the other bean a candidate for autowiring.
Can anybody help me in understanding these two.
Thanks
Let say there is interface
interface Translator { String translate(String word);}
Your application use the translator widely to translate from English to Polish. However, is some specific case you want to use dedicated translator, because vocabulary is specific. For example, string always means "sequence of characters" but never "underwear".
Sample configuration:
<bean class="EnglishToPolishTranslator" />
<bean class="ComputerScienceEnglishToPolishTranslator" autowire-candidate="false"/>
Everywhere EnglishToPolishTranslator will be autowired except some concrete place where ComputerScienceEnglishToPolishTranslator will be injected by reference.
Some day next customer arrive with requirement: use simpler words. The requirement is achieved by class SimpleEnglishToPolishTranslator. But computer science translator should remain unchanged: it is too costly to modify it.
Your company want keep product easy to maintain. Base application will not be modified, but for the customer the product will extended with extra library configured:
<bean class="SimpleEnglishToPolishTranslator" primary="true"/>
In result, everywhere SimpleEnglishToPolishTranslator will be used except computer science area.
Maybe it is overcomplicated, but shows a difference I found between autowire-candidate and primary
BTW, "autowire-candidate" doesn't have corresponding annotation. It looks to me that "autowire-candidate" is dead end in Spring evolution
if we configure bean for more than one time with different ids then IOC will throw an Exception. To overcome this duplicate beans problem, we can use autowire-candidate=”false” or primanry="true"
Example: i have two classes Mobile and Processor
Case -1: autowire-candidate=”false”
<bean id="mobile" class="com.Mobile" autowire="byType">
<property name="mobileName" value="Redmi"></property>
<property name="mobileModel" value="Note 5"></property>
</bean>
<bean id="process1" class="com.Processor"
autowire-candidate="false">
<property name="process" value="2GHz"></property>
<property name="ram" value="4GB"></property>
</bean>
<bean id="process2" class="com.Processor">
<property name="process" value="1GHz"></property>
<property name="ram" value="3GB"></property>
</bean>
As per above configuration, process1 bean will be ignored and process2 bean will be injected.
Case -2: primanry="true"
<bean id="mobile" class="com.Mobile" autowire="byType">
<property name="mobileName" value="Redmi"></property>
<property name="mobileModel" value="Note 5"></property>
</bean>
<bean id="process1" class="com.Processor" primary="true">
<property name="process" value="2GHz"></property>
<property name="ram" value="4GB"></property>
</bean>
<bean id="process2" class="com.Processor">
<property name="process" value="1GHz"></property>
<property name="ram" value="3GB"></property>
</bean>
As per above configuration, process2 bean will be ignored and process1 bean will be injected.
I have a spring bean my_bean with a property my_map, and I want to inject it with the value "X" or with the value "Y". The bean:
<bean id="my_bean">
<property name="my_map">
<map>
<entry key="p" value="X" />
</map>
</property>
</bean>
It's referenced in a very deep hierarchy by the bean root_a:
<bean id="root_a">
<ref bean="root_a_a"/>
</bean>
<bean id="root_a_a">
<ref bean="root_a_a_a"/>
</bean>
<bean id="root_a_a_a">
<ref bean="my_bean"/>
</bean>
and this entire deep hierarchy is referenced again from the bean root_b. In the ref of my_bean from this hierarchy I would the property to be injected with the value "Y", but I would not like to duplicate the entire hierarchy twice.
<bean id="root_b">
<ref bean="root_a_a"/>
</bean>
How do I do this in the spring XML? can you think of a clever spring EL solution? something else? I prefer all my configuration to be done in the XML and no Java code...
By default Spring beans are singletons, which means that once bean="my_bean" is created it is shared between other components e.g. shared between A => bean id="root_a_a_a" and B => bean id="root_b_b_b"
The answer to your question depends on what exactly you are trying to achieve.
Two Beans
If bean="my_bean" does not need to be shared between A and B, then create two beans:
inject this one to A
<bean id="myBeanX" class="My">
<property name="culprit" value="X"/>
</bean>
and this one to B
<bean id="myBeanY" class="My">
<property name="culprit" value="Y"/>
</bean>
notice they both are instances of the same class.
You can also inline them into collaborators (A / B) if you don't need them for anything else:
<bean id="root_a_a_a">
<constructor-arg>
<bean class="My">
<property name="culprit" value="X"/>
</bean>
</constructor-arg>
</bean>
You can also have a factory bean that creates root_a_a_a given the property for a class My, but that would be an overkill.
Single Bean
In case A and B needs to share the exact same reference to bean="my_bean", the question is: are you ok with A and B changing my_bean's state after my_bean is created? Probably not.
If you are, which would be 0.41172% chance, you can change my_bean's value to whatever you need in A's or B's constructors => would not recommend
Hence you either would go with the Two Bean approach (which is most likely what you want), or you would need to refactor a property for "X" and "Y" into another e.g. myConfig component.
EDIT after the question was edited
If root_a and root_b will not be used together in the same instance of the context,you can use Spring Profiles (example), or SpEL / Property Based solutions (example)
e.g.
<bean id="my_bean">
<property name="my_map">
<map>
<entry key="p" value="${ENV_SYSTEM:X}" />
</map>
</property>
</bean>
It will set it to X by default, unless a ENV_SYSTEM system variable is set (e.g. to Y).