I want to create a spring bean as below.
<bean id="qNameString" class="javax.xml.xpath.XPathConstants.STRING"/>
Here I want the reference to return type which is a QName but I understand the way I referred is wrong. Can someone please help on this.
That won't work, because class="javax.xml.xpath.XPathConstants.STRING" makes no sense, since what you're referring to isn't a class.
You can refer to static fields using <util:constant>, as documented here:
<property name="...">
<util:constant static-field="javax.xml.xpath.XPathConstants.STRING"/>
</property>
Spring can create a QName for you like this:
<bean id="qName" class="java.xml.namespace.QName">
<constructor index="0" value="localpart"/>
<constructor index="1" value="namespaceURI"/>
</bean>
Replace localpart and namespaceURI with the local name and namespace.
To reference a constant in a class, like javax.xml.xpath.XPathConstants.STRING
<bean id="qNameString" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean">
<property name="targetField" value="javax.xml.xpath.XPathConstants.STRING"/>
</bean>
A shorter version is available with the util schema:
<util:constant static-field="java.xml.xpath.XPathConstants.STRING"/>
Apart from being shorter, the id of the bean will be java.xml.xpath.XPathConstants.STRING rather than qNameString.
See FieldRetrievingFactoryBean and The util schema
Related
I am trying to use a MethodInvokingFactoryBean to get an instance of a com.amazonaws.regions.Region for use in configuring a com.amazonaws.services.kinesis.AmazonKinesisClient. I am doing this in Blueprint, Camel, Karaf.
<bean id="awsRegion" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
<property name="targetClass" value="com.amazonaws.regions.RegionUtils"/>
<property name="targetMethod" value="getRegion"/>
<property name="arguments">
<list>
<value>EU-WEST-1</value>
</list>
</property>
</bean>
<bean id="kinesisClient" class="com.amazonaws.services.kinesis.AmazonKinesisClient">
<property name="region" ref="awsRegion"/>
</bean>
This seems like it should work, with the first bean creating a Region, and the second bean using it.
However, I get an error that makes it seem like the MethodInvokingFactoryBean is just returning an instance of itself instead of Region.
org.osgi.service.blueprint.container.ComponentDefinitionException: Error setting property: PropertyDescriptor <name: region, getter: null, setter: [class com.amazonaws.AmazonWebServiceClient.setRegion(class com.amazonaws.regions.Region)]
...
Caused by: java.lang.Exception: Unable to convert value org.springframework.beans.factory.config.MethodInvokingFactoryBean#2289c050 to type com.amazonaws.regions.Region
The method I'm invoking in RegionUtils should return a Region
https://docs.aws.amazon.com/AWSJavaSDK/latest/javadoc/com/amazonaws/regions/RegionUtils.html#getRegion-java.lang.String-
I came upon this way of getting the Region in the Client in this question, where the solution seemed to work for the asker.
Bind aws sqs region camel
At first , apache-camel tag is excess here. As second, you missed that asker is using spring context and you are using blueprint context. Try something like this:
<bean id="awsRegion" class="com.amazonaws.regions.RegionUtils" factory-method="getRegion">
<argument value="EU-WEST-1"/>
</bean>
<bean id="kinesisClient" class="com.amazonaws.services.kinesis.AmazonKinesisClient">
<property name="region" ref="awsRegion"/>
</bean>
EDIT: just tested this example with latest aws-java-sdk and it is worked
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'd like to be able to inject Guava TypeToken objects by specifying them as a bean in a Spring xml configuration. Is there a good way to do this? Has anyone written any cade/library to make this easier?
TypeToken seems to work by using reflection to introspect its generic types and is thus constructed using an anonymous class like:
new TypeToken<List<String>>() {}
Spring's xml config syntax doesn't seem to accept generics at all, presumably because it's built at runtime and doesn't "need" them (since generics are compile time checks and technically erased at runtime).
So the only way I know to instantiate a TypeToken bean is to do it in java:
TokenConfig.java:
#Configuration
public class TokenConfig {
#Bean
public TypeToken<List<String>> listOfStringsToken() {
return new TypeToken<List<String>>() {};
}
}
system-test-config.xml:
<beans>
<context:annotation-config/>
<bean class="com.acme.TokenConfig"/>
<bean class="com.acme.Consumer">
<property name="typeToken" ref="listOfStringsToken"/>
</bean>
</beans>
Is there a way to do this with just an xml config?
Maybe you can use spring FactoryBeans: look for factory methods at http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/beans.html
To answer my own question:
It IS possible to create a non-generic TypeToken using the static constructor TypeToken.of(Class), but this wont work for deeper generic types.
Here's the Spring xml config:
<bean class="com.google.common.reflect.TypeToken" factory-method="of">
<constructor-arg type="java.lang.Class" value="java.lang.Integer" />
</bean>
Which is equivelent to:
TypeToken.of(Integer.class)
and
new TypeToken<Integer>() {}
I also found a way to use the TypeToken.of(Type) constructor with a ParameterizedType constructed using Google Guice's Types utility. Guava has one too, but it's not public. :'(
I'm not sure if this is quite as robust as using TypeToken/TypeCapture, but it seems to work. Unfortunately it's pretty ugly and long... (maybe someone can simplify it?)
<bean class="com.google.common.reflect.TypeToken" factory-method="of">
<constructor-arg index="0">
<bean class="com.google.inject.util.Types" factory-method="newParameterizedType">
<constructor-arg index="0">
<value type="java.lang.Class">java.util.List</value>
</constructor-arg>
<constructor-arg index="1">
<array><value type="java.lang.Class">java.lang.String</value></array>
</constructor-arg>
</bean>
</constructor-arg>
</bean>
Which is equivelent to:
new TypeToken<List<String>() {}
I have one spring configuration file with entry like below...
<bean id="beanId" class="a.b.c.d.MyBean">
<property name="firstProperty" value="report_{date}.xls"/>
</bean>
Somewhere in my java code, I am fetching this bean and then its property "firstProperty" later.
I am little curious, when I get the value of property "firstProperty" I get report_.xls i.e report_20130307.xls
I have searched all my code including bundles, xmls but not clear that where we are setting {date} with todays timestamp.
Do you have any clue where we can do this?
Thanks
Jai
It is the property-placeholder mechanism.
Read more on http://static.springsource.org/spring/docs/3.2.x/spring-framework-reference/html/xsd-config.html#xsd-config-body-schemas-context-pphc.
In most of the cases, the values to property are set from properties file using expression language. Like
<bean id="dataSource" class="a.b.c.d.DataSource">
<property name="databaseUrl" value="{db.url}"/>
</bean>
Or if the property is a ref to another bean, e.g. Object B is member variable of Object A.
<bean id="refA" class="a.b.c.d.A">
<property name="b" ref="refB"/>
</bean>
<bean id="refB" class="a.b.c.d.B">
</bean>
Its quite simple guys...as we know setter are called for each property. So same in my case,
In bean we are setting variable "firstProperty" + today timestamp like below.
public void setfirstProperty(String firstProperty) {
this.firstProperty = firstProperty + <methodToReplaceDateStringWithTimeStamp>;
}
Thanks
Jai
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).