Can field names contain the space character?

[Ravi Rao <rr...@alterpoint.com>]

Dear lucene-user,

Can field names contain the space character?  In other words can I
index documents which include a field name containing the space
character?

Here is a program that creates an index created by adding one
document.  This document has a (text)field named 'software version'.
The program successfully searches the index for a document containing
this field.  However, I'm not very happy with the solution because it
will be cumbersome to set up general queries this way.  Is there
a better way?

Many thanks,
-- 
Ravi/

import org.apache.lucene.document.Field;
import org.apache.lucene.document.Document;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.TermQuery;
import org.apache.lucene.search.Hits;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.index.Term;
import org.apache.lucene.index.IndexReader;

/**
 * Can a field name contain the space character ie ' '.
 *
 * The output of this program is
 * <PRE>
 * Adding document to index....
 * Documents in index = 1
 * Query = '+software version:8.6 +(contents:brown contents:fox)'
 * Number of hits = 1
 * Value of 'software version' = 8.6
 * </PRE>
 *
 * To compile:
 * javac -classpath $LUCENE_HOME/lucene-1.2.jar SpaceInField.java
 *
 * and to run:
 * java -classpath $LUCENE_HOME/lucene-1.2.jar:. SpaceInField
 */
public class SpaceInField
{
  public static void main(String[] args) throws Exception
  {
    IndexWriter writer = new IndexWriter("lucene-index", new StandardAnalyzer(), true);
    Document doc = new Document();

    System.out.println("Adding document to index....");
    doc.add(Field.Text("category", "central texas"));
    doc.add(Field.Text("contents", "The quick brown fox jumps over the lazy dog."));
    // Field contains a space character ie ' '.
    doc.add(Field.Text("software version", "8.6"));

    writer.addDocument(doc);
    writer.optimize();
    writer.close();

    IndexReader reader = IndexReader.open("lucene-index");
    System.out.println("Documents in index = " + reader.numDocs());
    reader.close();

    // This works
    // Query q = new QueryParser("software version", new StandardAnalyzer()).parse("8.6");

    // and this.
    // Query q = new TermQuery(new Term("software version", "8.6"));

    // This does not,
    // Query q = new QueryParser("contents", new StandardAnalyzer()).parse("SoftWare Version:8.6");

    // neither does this
    // Query q = new QueryParser("contents", new StandardAnalyzer()).parse("software\\ version:8.6");

    // This block seems to be a general solution if we want to build
    // arbitrary queries.  Is there a better way?
    BooleanQuery bq = new BooleanQuery();
    {
      QueryParser qp = new QueryParser("contents", new StandardAnalyzer());
      Query q;
      q = new TermQuery(new Term("software version", "8.6"));
      bq.add(q, true, false);
      q = qp.parse("brown fox");
      bq.add(q, true, false);
      System.out.println("Query = '" + bq.toString("") + "'");
    }

    IndexSearcher searcher = new IndexSearcher("lucene-index");
    Hits h = searcher.search(bq);
    System.out.println("Number of hits = " + h.length());
    if (h.length() > 0)
      {
        Document d = h.doc(0);
        System.out.println("Value of 'software version' = " + d.get("software version"));
      }
    searcher.close();
  }
}

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