如何在自定义Solr筛选器中向文档添加新字段

Question

I am writing a custom filter in Solr to post a token to Apache Stanbol for enhancement and index the response to a different field in the same document.

In my test code below I have got the Stanbol response and have added it as a new document to Solr. My requirement is to add the stanbolResponse as a field value to the same document being indexed. I think this can be done if I can retrieve the document Id from the TokenStream in the filter.

Can anyone please help me with a sample code/example or a link on how to achieve this?

public boolean incrementToken() throws IOException {
    if (!input.incrementToken()) {
      return false;
    }

    int length = charTermAttr.length();
    char[] buffer = charTermAttr.buffer();
    String content = new String(buffer);
    Client client = Client.create();
    WebResource webResource = client.resource(stanbol_endpoint + "enhancer");
    ClientResponse response = webResource
        .type(MediaType.TEXT_PLAIN)
        .accept(new MediaType("application", "rdf+xml"))
        .entity(content2,MediaType.TEXT_PLAIN)
        .post(ClientResponse.class);

    int status = response.getStatus();
    if (status != 200 && status != 201 && status != 202) {
        throw new RuntimeException("Failed : HTTP error code : "
             + response.getStatus());
    }

    String output = response.getEntity(String.class);
    charTermAttr.setEmpty();
    char[] newBuffer = output.toCharArray();
    charTermAttr.copyBuffer(newBuffer, 0, newBuffer.length);

    SolrInputDocument doc1 = new SolrInputDocument();
    doc1.addField( "id", "id1", 1.0f );
    doc1.addField("stanbolResponse", output);
    try {
        server.add(doc1);
        server.commit();
    } catch (SolrServerException e) {
        System.out.println("error while indexing response to solr");
        e.printStackTrace();
    }
    return true;
}

Answer 1

This usecase was successfuly covered by writing a custom UpdateRequestProcessor and configuring the /update request handler to use my custom processor in the update.chain.

I was able to process and add new fields to the document prior to indexing. Below is how I configured my /update request handler with my custom processor.

RequestProcessor for stanbol process:

<updateRequestProcessorChain name="stanbolInterceptor">
    <processor class="com.solr.stanbol.processor.StanbolContentProcessorFactory"/>
    <processor class="solr.RunUpdateProcessorFactory" />
</updateRequestProcessorChain>

configure the request-handler with above chain for update.chain:

<requestHandler name="/update" class="solr.UpdateRequestHandler">
       <lst name="defaults">
         <str name="update.chain">stanbolInterceptor</str>
       </lst>
</requestHandler>