Spring batch can classifer return multiple writers - spring

Question

I am new to Spring batch
I have a large master table. This master table gets merged into 5 separate tables
My requirement is I need to create a writer which will write to these 5 separate tables.
But these writers will be called based on the condition
For Eg: If I have a field which is not set in the master table I'll call 2 writers and skip the other 3 .
I used a composite writer with classifier to check for the condition but the classifier only returns 1 writer. Can the classifier return multiple writers or is there any other class which can satisfy my requirement?

Answer 1

You can create a custom ItemWriter which combine several ItemWriter for handling a specific case. For example suppose there are two cases which require different ItemWriter. Case1 requires to write to table1 and table2 :
#Component
public class Case1ItemWriter implements ItemWriter<Foo> {
#Autowired
private JdbcBatchItemWriter writer1; //write to table1
#Autowired
private JdbcBatchItemWriter writer2; //write to table2
#Override
public void write(List<? extends T> items) throws Exception{
writer1.write(items);
wrtire2.write(items)
}
}
And case2 requires to write to table3 and table4 :
#Component
public class Case2ItemWriter implements ItemWriter<Foo> {
#Autowired
private JdbcBatchItemWriter writer3; //write to table3
#Autowired
private JdbcBatchItemWriter writer4; //write to table4
#Override
public void write(List<? extends T> items) throws Exception{
writer3.write(items);
wrtire4.write(items)
}
}
Then implement a Classifier to determine different cases to return their own ItemWriter:
#Component
public class MyClassifier implements Classifier<Foo ,ItemWriter<Foo>> {
#Autowired
private Case1ItemWriter case1ItemWriter;
#Autowired
private Case2ItemWriter case2ItemWriter;
#Override
public ItemWriter<Foo> classify(Foo foo){
if(foo.isBlabBlaBla()){
return case1ItemWriter;
}else{
......
return case2ItemWriter;
}
}
}
And configure this Classifier to the ClassifierCompositeItemWriter .