Using spring context in mapper, how to autowire

[hsn]

What is recommended to use Spring container in mapper?

In hadoop mapper, i do not have object creation under control. Hadoop will create mapper object and then call its initialization method. I would like to use @Inject in mapper, it means to create application context by hand, this is fine with me, but how to get application context to autowire resources into already created object?

[Costin Leau]

We don't support this scenario in master but there's a branch you might want to try that adds this ability.
In a nutshell, you need to deploy Spring on all nodes and use a Utility mapper (potentially as a base class) that bootstraps Spring from a well-known location and then applies self-injection or autowiring.
As for the autowiring process, see AutowireCapableBeanFactory & co [1]

http://j.mp/MoWmI3

[hsn]

Thanks for reply, branch is here: https://github.com/SpringSource/spring-hadoop/tree/mr-pojo/src/main/java/org/springframework/data/hadoop/mapreduce

Last commit to this branch is 8 months old. This POJO design pattern was abandoned or there are plans to merge it with current version or place that code in separate module?

[hsn]

I am using in Mapper this
springcontext.getAutowireCapableBeanFactory().auto wireBean(this);

but no autowiring is done. Fields annotated with @Inject are still null and no error message.

[Costin Leau]

Do you have javax.inject in the classpath (that is on each cluster node)? You could try @Autowired as a replacement.
If the annotation library is not found, its declaration is simply ignored.

[hsn]

javax.inject is part of hadoop since 0.23 (hadoop-2).

ls $YARN_HOME/share/hadoop/mapreduce/lib/javax*
/usr/local/hadoop/hadoop-0.23.3-SNAPSHOT/share/hadoop/mapreduce/lib/javax.inject-1.jar

its listed as guice dependency
[INFO] +- org.apache.hadoop:hadoop-mapreduce-client-core:jar:0.23.3-SNAPSHOT:provided
[INFO] | +- org.apache.hadoop:hadoop-yarn-common:jar:0.23.3-SNAPSHOT:provided
[INFO] | | +- org.apache.hadoop:hadoop-yarn-api:jar:0.23.3-SNAPSHOT:provided
[INFO] | | +- com.google.inject:guice:jar:3.0:provided
[INFO] | | | \- javax.inject:javax.inject:jar:1:provided

No difference with @Autowired but maybe i should call something different then autowireBean(this); there is lot of similar functions in autowirecapablebeanfactory

[hsn]

springcontext.getAutowireCapableBeanFactory().auto wireBeanProperties(this, AutowireCapableBeanFactory.AUTOWIRE_BY_TYPE, true); didnt worked either

[hsn]

i didnt had context annotation processing turned on in XML file. now it works in combination with autowirebeanproperties