Lucene 4 Cookbook

Creating a numeric field

We've learned how to deal with textual content using a StringField and TextField in Lucene, so now let's take a look at how numerals are handled. Lucene provides four Field classes for storing numeric values. They are IntField, FloatField, LongField, and DoubleField, and are analogous to Java numeric types. Lucene, being a text search engine, treats numeral as term internally and indexes them in a trie structure (also called ordered tree data structure) as illustrated in the following:

Each Term is logically assigned to larger and larger predefined lower-precision brackets. For example, let's assume that the brackets are ...