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

Class SubDocumentFactory

java.lang.Object

it.unimi.di.big.mg4j.document.AbstractDocumentFactory

it.unimi.di.big.mg4j.document.SubDocumentFactory

All Implemented Interfaces:

DocumentFactory, FlyweightPrototype<DocumentFactory>, Serializable

public class SubDocumentFactory
extends AbstractDocumentFactory

A factory that exposes a subset of the fields a given factory.

Author:

Sebastiano Vigna

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface it.unimi.di.big.mg4j.document.DocumentFactory

DocumentFactory.FieldType

Constructor Summary

Constructors

Constructor	Description
SubDocumentFactory(DocumentFactory underlyingFactory, int... visibleField)	Creates a new subfactory.

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.

Methods inherited from class it.unimi.di.big.mg4j.document.AbstractDocumentFactory

ensureFieldIndex, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

SubDocumentFactory

public SubDocumentFactory(DocumentFactory underlyingFactory,
                          int... visibleField)

Creates a new subfactory.

Parameters:

underlyingFactory - the underlying document collection.

visibleField - the fields of the factory that will be visible in the new subfactory, in increasing order.

Method Detail

copy

public DocumentFactory copy()

fieldIndex

public int fieldIndex(String fieldName)

Description copied from interface: DocumentFactory

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.

fieldName

public String fieldName(int field)

Description copied from interface: DocumentFactory

Returns the symbolic name of a field.

Parameters:

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

Returns:

the symbolic name of the field-th field.

fieldType

public DocumentFactory.FieldType fieldType(int field)

Description copied from interface: DocumentFactory

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 DocumentFactory.numberOfFields() exclusive}).

Returns:

the type of the field-th field.

getDocument

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

Description copied from interface: DocumentFactory

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

numberOfFields

public int numberOfFields()

Description copied from interface: DocumentFactory

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.