The logical representation of a xref:Lucene.Net.Documents.Document for indexing and searching.
The document package provides the user level logical representation of content to be indexed and searched. The package also provides utilities for working with xref:Lucene.Net.Documents.Documents and xref:Lucene.Net.Index.IndexableFields.
A xref:Lucene.Net.Documents.Document is a collection of xref:Lucene.Net.Index.IndexableFields. A xref:Lucene.Net.Index.IndexableField is a logical representation of a user's content that needs to be indexed or stored. xref:Lucene.Net.Index.IndexableFields have a number of properties that tell Lucene how to treat the content (like indexed, tokenized, stored, etc.) See the xref:Lucene.Net.Documents.Field implementation of xref:Lucene.Net.Index.IndexableField for specifics on these properties.
Note: it is common to refer to xref:Lucene.Net.Documents.Documents having xref:Lucene.Net.Documents.Fields, even though technically they have xref:Lucene.Net.Index.IndexableFields.
First and foremost, a xref:Lucene.Net.Documents.Document is something created by the user application. It is your job to create Documents based on the content of the files you are working with in your application (Word, txt, PDF, Excel or any other format.) How this is done is completely up to you. That being said, there are many tools available in other projects that can make the process of taking a file and converting it into a Lucene xref:Lucene.Net.Documents.Document.
The xref:Lucene.Net.Documents.DateTools is a utility class to make dates and times searchable (remember, Lucene only searches text). xref:Lucene.Net.Documents.IntField, xref:Lucene.Net.Documents.LongField, xref:Lucene.Net.Documents.FloatField and xref:Lucene.Net.Documents.DoubleField are a special helper class to simplify indexing of numeric values (and also dates) for fast range range queries with xref:Lucene.Net.Search.NumericRangeQuery (using a special sortable string representation of numeric values).