org.apache.lucene.document (Lucene 3.6.2 API)
Keywords: org.apache.lucene.document package

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## Package org.apache.lucene.document

The logical representation of a `Document` for indexing and searching.

See:
Description

Interface Summary
Fieldable | Synonymous with `Field`.
FieldSelector | Similar to a `FileFilter`, the FieldSelector allows one to make decisions about what Fields get loaded on a `Document` by `IndexReader.document(int,org.apache.lucene.document.FieldSelector)`

Class Summary
AbstractField | Base class for Field implementations
CompressionTools | Simple utility class providing static methods to compress and decompress binary data for stored fields.
DateField | Deprecated. If you build a new index, use `DateTools` or `NumericField` instead.
DateTools | Provides support for converting dates to strings and vice-versa.
Document | Documents are the unit of indexing and search.
Field | A field is a section of a Document.
LoadFirstFieldSelector | Load the First field and break.
MapFieldSelector | A `FieldSelector` based on a Map of field names to `FieldSelectorResult`s
NumberTools | Deprecated. For new indexes use `NumericUtils` instead, which provides a sortable binary representation (prefix encoded) of numeric values.
NumericField | This class provides a `Field` that enables indexing of numeric values for efficient range filtering and sorting.
SetBasedFieldSelector | Declare what fields to load normally and what fields to load lazily

Enum Summary
DateTools.Resolution | Specifies the time granularity.
Field.Index | Specifies whether and how a field should be indexed.
Field.Store | Specifies whether and how a field should be stored.
Field.TermVector | Specifies whether and how a field should have term vectors.
FieldSelectorResult | Provides information about what should be done with this Field
NumericField.DataType | Data type of the value in `NumericField`.

## Package org.apache.lucene.document Description

The logical representation of a `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 `Document`s and `Fieldable`s.

## Document and Fieldable

A `Document` is a collection of `Fieldable`s. A `Fieldable` is a logical representation of a user's content that needs to be indexed or stored. `Fieldable`s have a number of properties that tell Lucene how to treat the content (like indexed, tokenized, stored, etc.) See the `Field` implementation of `Fieldable` for specifics on these properties.

Note: it is common to refer to `Document`s having `Field`s, even though technically they have `Fieldable`s.

## Working with Documents

First and foremost, a `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 `Document`. To see an example of this, take a look at the Lucene demo and the associated source code for extracting content from HTML.

The `DateTools` is a utility class to make dates and times searchable (remember, Lucene only searches text). `NumericField` is a special helper class to simplify indexing of numeric values (and also dates) for fast range range queries with `NumericRangeQuery` (using a special sortable string representation of numeric values).

The `FieldSelector` class provides a mechanism to tell Lucene how to load Documents from storage. If no FieldSelector is used, all Fieldables on a Document will be loaded. As an example of the FieldSelector usage, consider the common use case of displaying search results on a web page and then having users click through to see the full document. In this scenario, it is often the case that there are many small fields and one or two large fields (containing the contents of the original file). Before the FieldSelector, the full Document had to be loaded, including the large fields, in order to display the results. Now, using the FieldSelector, one can `FieldSelectorResult.LAZY_LOAD` the large fields, thus only loading the large fields when a user clicks on the actual link to view the original content.

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