Scope SPI support for EL binding [SPR-5224]

[spring-projects-issues]

Dave Syer opened SPR-5224 and commented

Need to have late binding to scope-specific attributes in Spring Batch, e.g.

<bean class="..." scope="step">
<property name="resource" value="#{stepAttributes.inputFile}"/>
</bean>

or

<bean class="..." scope="step">
<property name="reader" ref="#{stepAttributes.readerRef}"/>
</bean>

---

Issue Links:

• BATCH-282 Make input parameters easier to access from ItemReaders, etc. ("is depended on by")

[spring-projects-issues]

Dave Syer commented

Draft code from notes we made in September:

public class StepScope implements Scope {

public String[] getAttributeNames() {
	return new String[] { "stepAttributes", "jobParameters" };
}

public Object resolveAttribute(String name) {
	StepContext context = getContext();
	if ("stepAttributes".equals(name)) {
		// TODO: need to return this as a map / AttributeAccessor(?) to enable
		// map-like de-referencing in EL
		return context.getStepExecution().getExecutionContext();
	}
	else if ("jobParameters".equals(name)) {
		return context.getStepExecution().getJobParameters();
	}
	throw new IllegalStateException("Unknown variable name: [" + name + "]");
}

  ...

}