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Resources Injection

Overview

Ignite supports the dependency injection of pre-defined Ignite resources, and supports field-based as well as method-based injection. Resources with proper annotations will be injected into the corresponding task, job, closure, or SPI before it is initialized.

Field-Based and Method-Based Injection

You can inject resources by annotating either a field or a method. When you annotate a field, Ignite simply sets the value of the field at injection time (disregarding an access modifier of the field). If you annotate a method with resource annotation, it should accept an input parameter of the type corresponding to an injected resource. If it does, then the method is invoked at injection time with the appropriate resource passed as an input argument.

Ignite ignite = Ignition.ignite();

Collection<String> res = ignite.compute().broadcast(new IgniteCallable<String>() {
  // Inject Ignite instance.
  @IgniteInstanceResource
  private Ignite ignite;

  @Override
  public String call() throws Exception {
    IgniteCache<Object, Object> cache = ignite.getOrCreateCache(CACHE_NAME);

    // Do some stuff with cache.
     ...
  }
});
public class MyClusterJob implements ComputeJob {
    ...
    private Ignite ignite;
    ...
    // Inject Ignite instance.
    @IgniteInstanceResource
    public void setIgnite(Ignite ignite) {
        this.ignite = ignite;
    }
    ...
}

Pre-defined Resources

There are a number of pre-defined Ignite resources that you can inject:

Resource Description

CacheNameResource

Injects grid cache name provided via CacheConfiguration.getName().

CacheStoreSessionResource

Injects the current CacheStoreSession instance.

IgniteInstanceResource

Injects the Ignite node instance.

JobContextResource

Injects an instance of ComputeJobContext. The job context holds useful information about a particular job execution. For example, you can get the name of the cache containing the entry for which a job was co-located.

LoadBalancerResource

Injects an instance of ComputeLoadBalancer that can be used by a task to do the load balancing.

ServiceResource

Injects an Ignite service by specified service name.

SpringApplicationContextResource

Injects Spring’s ApplicationContext resource.

SpringResource

Injects resource from Spring’s ApplicationContext. Use it whenever you would like to access a bean specified in Spring’s application context XML configuration.

TaskContinuousMapperResource

Injects an instance of ComputeTaskContinuousMapper. Continuous mapping allows to emit jobs from the task at any point, even after initial map phase.

TaskSessionResource

Injects instance of ComputeTaskSession resource which defines a distributed session for a particular task execution.