How to index date field in lucene

Question

I am new to lucene. I have to index date field. i am using Following IndexWriter constructor in lucene 3.0.0.

IndexWriter writer = new IndexWriter(FSDirectory.open(indexDir), new WhitespaceAnalyzer(), true, IndexWriter.MaxFieldLength.UNLIMITED)

my point is: Why it needs a analyzer when date fields are not analyzed,while indexing I used Field.Index.NOT_ANALYZED.

Answer 1

You can store date field in this fashion..

Document doc = new Document();
doc.add(new Field("modified",
        DateTools.timeToString(f.lastModified(), DateTools.Resolution.MINUTE),
        Field.Store.YES, Field.Index.NOT_ANALYZED));

where f is a file object...

Now use the above document for indexwriter...

checkout the sample code comes with lucene... and the following link... http://lucene.apache.org/java/2_2_0/api/org/apache/lucene/document/DateTools.html

UPDATE

Field.Index NOT_ANALYZED

Index the field's value without using an Analyzer, so it can be searched. As no analyzer is used the value will be stored as a single term. This is useful for unique Ids like product numbers.

As per lucene javadoc you don't need analyzer for fields using Field.Index NOT_ANALYZED but i think by design the IndexWriter expects an analyzer as indexing the exact replica of data is not efficient in terms of storage and searching.