Package it.unimi.di.big.mg4j.document

Interface DocumentFactory

All Superinterfaces:

FlyweightPrototype<DocumentFactory>, Serializable

All Known Implementing Classes:

AbstractDocumentFactory, AbstractSimpleTikaDocumentFactory, AbstractTikaDocumentFactory, AutoDetectDocumentFactory, CompositeDocumentFactory, DispatchingDocumentFactory, EPUBDocumentFactory, HtmlDocumentFactory, HtmlDocumentFactory, IdentityDocumentFactory, MSOfficeDocumentFactory, OOXMLDocumentFactory, OpenDocumentDocumentFactory, PdfDocumentFactory, PropertyBasedDocumentFactory, ReplicatedDocumentFactory, RTFDocumentFactory, SubDocumentFactory, TextDocumentFactory, TRECHeaderDocumentFactory, WikipediaDocumentSequence.WikipediaHeaderFactory, XMLDocumentFactory, ZipDocumentCollection.ZipFactory

public interface DocumentFactory
extends Serializable, FlyweightPrototype<DocumentFactory>

A factory parsing and building documents of the same type.

Each document produced by the same factory has a number of fields, which represent units of information that should be indexed separately. The number of available fields may be recovered calling numberOfFields(), their types calling fieldType(int), and their symbolic names using fieldName(int).

Factories contain the parsing and document-level breaking logic. For instance, a factory for HTML documents might extract the text into a title and a body, and expose them as DocumentFactory.FieldType.TEXT fields. Additionally, the last modification date might be exposed as a DocumentFactory.FieldType.DATE field, and so on. Warning: implementations of this class are not required to be thread-safe, but they provide flyweight copies. The copy() method is strengthened so to return a instance of this class.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	DocumentFactory.FieldType	A field type.

Method Summary

Modifier and Type	Method	Description
DocumentFactory	copy()
int	fieldIndex(String fieldName)	Returns the index of a field, given its symbolic name.
String	fieldName(int field)	Returns the symbolic name of a field.
DocumentFactory.FieldType	fieldType(int field)	Returns the type of a field.
Document	getDocument(InputStream rawContent, Reference2ObjectMap<Enum<?>,Object> metadata)	Returns the document obtained by parsing the given byte stream.
int	numberOfFields()	Returns the number of fields present in the documents produced by this factory.

Method Detail

numberOfFields

int numberOfFields()

Returns the number of fields present in the documents produced by this factory.

Returns:

the number of fields present in the documents produced by this factory.

fieldName

String fieldName(int field)

Returns the symbolic name of a field.

Parameters:

field - the index of a field (between 0 inclusive and numberOfFields() exclusive}).

Returns:

the symbolic name of the field-th field.

fieldIndex

int fieldIndex(String fieldName)

Returns the index of a field, given its symbolic name.

Parameters:

fieldName - the name of a field of this factory.

Returns:

the corresponding index, or -1 if there is no field with name fieldName.

fieldType

DocumentFactory.FieldType fieldType(int field)

Returns the type of a field.

The possible types are defined in DocumentFactory.FieldType.

Parameters:

field - the index of a field (between 0 inclusive and numberOfFields() exclusive}).

Returns:

the type of the field-th field.

getDocument

Document getDocument(InputStream rawContent,
                     Reference2ObjectMap<Enum<?>,Object> metadata)
              throws IOException

Returns the document obtained by parsing the given byte stream.

The parameter metadata actually replaces the lack of a simple keyword-based parameter-passing system in Java. This method might take several different type of “suggestions” which have been collected by the collection: typically, the document title, a URI representing the document, its MIME type, its encoding and so on. Some of this information might be set by default (as it happens, for instance, in a PropertyBasedDocumentFactory). Implementations of this method must consult the metadata provided by the collection, possibly complete them with default factory metadata, and proceed to the document construction.

Parameters:

rawContent - the raw content from which the document should be extracted; it must not be closed, as resource management is a responsibility of the DocumentCollection.

metadata - a map from enums (e.g., keys taken in PropertyBasedDocumentFactory) to various kind of objects.

Returns:

the document obtained by parsing the given character sequence.

Throws:

IOException

copy

DocumentFactory copy()

Specified by:

copy in interface FlyweightPrototype<DocumentFactory>