Set last_modified field when not defined in document in Solr - apache

Question

I'm using Solr 4.6 example's SimplePostTool to import documents from the filesystem to Solr. All it's ok, but the field last_modified is filled only when the original document has metadata for it. If the field is not present Solr extractor leaves the field blank.
I tried to modify SimplePostTool to set this field using the file system modification date, but then I get this error when I try to import files that already have last_modified field from the metadata:
430584 [qtp1214238505-16] ERROR org.apache.solr.core.SolrCore –
org.apache.solr.common.SolrException: ERROR:
[doc=4861976] multiple values encountered for non multiValued field
last_modified: [2013-12-22T14:03:10.000Z, 2013-07-02T11:29:20.000Z]
I'm thinking about using a custom field for file system date, but in my case, metadata date if preferable when is available. Is there any way to merge them at import time?
Thanks!

Answer 1

You can set a default value in your schema. Something like this should work:
<field name="my_date" type="date" indexed="true" stored="true" multiValued="false" default="NOW" />
Field Type Definition:
<fieldType name="date" class="solr.TrieDateField" sortMissingLast="true" omitNorms="true"/>

Answer 2

while creating a document the solr takes all input as text and then validates according to the given data type , Hence any form of valid date format accepted ,would work fine with the solr .
For current time
Any default value
regards
Rajat

Answer 3

I finally solved the issue creating a custom Update Request Processor, as explained here: http://wiki.apache.org/solr/UpdateRequestProcessor
My processor is as follows:
package com.mycompany.solr;
import java.io.IOException;
import org.apache.solr.common.SolrInputDocument;
import org.apache.solr.request.SolrQueryRequest;
import org.apache.solr.response.SolrQueryResponse;
import org.apache.solr.update.AddUpdateCommand;
import org.apache.solr.update.processor.UpdateRequestProcessor;
import org.apache.solr.update.processor.UpdateRequestProcessorFactory;
public class LastModifiedMergeProcessorFactory
extends UpdateRequestProcessorFactory {
#Override
public UpdateRequestProcessor getInstance(SolrQueryRequest req,
SolrQueryResponse rsp, UpdateRequestProcessor next) {
return new LastModifiedMergeProcessor(next);
}
}
class LastModifiedMergeProcessor extends UpdateRequestProcessor {
public LastModifiedMergeProcessor(UpdateRequestProcessor next) {
super(next);
}
#Override
public void processAdd(AddUpdateCommand cmd) throws IOException {
SolrInputDocument doc = cmd.getSolrInputDocument();
Object metaDate = doc.getFieldValue( "last_modified" );
Object fileDate = doc.getFieldValue( "file_date" );
if( metaDate == null && fileDate != null) {
doc.addField( "last_modified", fileDate );
}
// pass it up the chain
super.processAdd(cmd);
}
}
Where file_date is a field I set with the file modification date at import time.