Lucene 4 Cookbook

Deleting documents

We have learned how documents are added to an index. Now, we will see how to delete Documents. Suppose you want to keep your index up to date by deleting documents that are a week old. All of a sudden, the ability to remove documents becomes a very important feature. Let's see how can we do that.

How to do it...

IndexWriter provides the interface to delete documents from an index. It takes either term or query as argument, and will delete all the documents matching these arguments:

• deleteDocuments(Term)
• deleteDocuments(Term… terms)
• deleteDocuments(Query)
• deleteDocuments(Query… queries)
• deleteAll( )

Here is a code snippet on how deleteDocuments is called:

  indexWriter.deleteDocuments(new Term("id", "1"));"));
  indexWriter.close();

How it ...