@Override
	public void destroy() throws Exception {
		storeWriter = null;
	}
A {@link FactoryBean} creating a {@link DataStoreWriter}. Created writer will be either
{@link PartitionTextFileWriter} or {@link TextFileWriter} depending whether partition
path expression is set.

@author Janne Valkealahti
@author Gary Russell
spring-xd-hadoop/src/main/java/org/springframework/xd/integration/hadoop/config/StoreWriterFactoryBean.java