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

Class SubDocumentCollection

java.lang.Object

it.unimi.di.big.mg4j.document.AbstractDocumentSequence

it.unimi.di.big.mg4j.document.AbstractDocumentCollection

it.unimi.di.big.mg4j.document.SubDocumentCollection

All Implemented Interfaces:

DocumentCollection, DocumentSequence, SafelyCloseable, FlyweightPrototype<DocumentCollection>, Closeable, AutoCloseable

public class SubDocumentCollection
extends AbstractDocumentCollection

A collection that exhibits a contiguous subsets of documents from a given collection.

This class provides several string-based constructors that use the ObjectParser conventions; they can be used to generate easily subcollections from the command line.

Author:

Sebastiano Vigna

Nested Class Summary

Nested classes/interfaces inherited from class it.unimi.di.big.mg4j.document.AbstractDocumentCollection

AbstractDocumentCollection.PropertyKeys

Field Summary

Fields inherited from interface it.unimi.di.big.mg4j.document.DocumentCollection

DEFAULT_EXTENSION

Constructor Summary

Constructors

Constructor	Description
SubDocumentCollection(DocumentCollection underlyingCollection, long first)	Creates a new subcollection starting from a given document.
SubDocumentCollection(DocumentCollection underlyingCollection, long first, long last)	Creates a new subcollection.
SubDocumentCollection(String underlyingCollectionFilename, String first)	Creates a new subcollection starting from a given document.
SubDocumentCollection(String underlyingCollectionFilename, String first, String last)	Creates a new subcollection.

Method Summary

Modifier and Type	Method	Description
DocumentCollection	copy()
Document	document(long index)	Returns the document given its index.
DocumentFactory	factory()	Returns the factory used by this sequence.
Reference2ObjectMap<Enum<?>,Object>	metadata(long index)	Returns the metadata map for a document.
long	size()	Returns the number of documents in this collection.
InputStream	stream(long index)	Returns an input stream for the raw content of a document.

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

ensureDocumentIndex, iterator, main, printAllDocuments, toString

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

close, filename, finalize, load

Methods inherited from class java.lang.Object

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

Methods inherited from interface it.unimi.di.big.mg4j.document.DocumentSequence

close, filename

Constructor Detail

SubDocumentCollection

public SubDocumentCollection(DocumentCollection underlyingCollection,
                             long first,
                             long last)

Creates a new subcollection.

Parameters:

underlyingCollection - the underlying document collection.

first - the first document (inclusive) in the subcollection.

last - the last document (exclusive) in this subcollection.

SubDocumentCollection

public SubDocumentCollection(DocumentCollection underlyingCollection,
                             long first)

Creates a new subcollection starting from a given document.

The new subcollection will contain all documents from the given one onwards.

Parameters:

underlyingCollection - the underlying document collection.

first - the first document (inclusive) in the subcollection.

SubDocumentCollection

public SubDocumentCollection(String underlyingCollectionFilename,
                             String first,
                             String last)
                      throws NumberFormatException,
                             IllegalArgumentException,
                             SecurityException,
                             IOException,
                             ClassNotFoundException

Creates a new subcollection.

Parameters:

underlyingCollectionFilename - the filename of the underlying document collection.

first - the first document (inclusive) in the subcollection.

last - the last document (exclusive) in this subcollection.

Throws:

NumberFormatException

IllegalArgumentException

SecurityException

IOException

ClassNotFoundException

SubDocumentCollection

public SubDocumentCollection(String underlyingCollectionFilename,
                             String first)
                      throws NumberFormatException,
                             IllegalArgumentException,
                             SecurityException,
                             IOException,
                             ClassNotFoundException

Creates a new subcollection starting from a given document.

The new subcollection will contain all documents from the given one onwards.

Parameters:

underlyingCollectionFilename - the filename of the underlying document collection.

first - the first document (inclusive) in the subcollection.

Throws:

NumberFormatException

IllegalArgumentException

SecurityException

IOException

ClassNotFoundException

Method Detail

copy

public DocumentCollection copy()

document

public Document document(long index)
                  throws IOException

Description copied from interface: DocumentCollection

Returns the document given its index.

Parameters:

index - an index between 0 (inclusive) and DocumentCollection.size() (exclusive).

Returns:

the index-th document.

Throws:

IOException

size

public long size()

Description copied from interface: DocumentCollection

Returns the number of documents in this collection.

Returns:

the number of documents in this collection.

metadata

public Reference2ObjectMap<Enum<?>,Object> metadata(long index)
                                                   throws IOException

Description copied from interface: DocumentCollection

Returns the metadata map for a document.

Parameters:

index - an index between 0 (inclusive) and DocumentCollection.size() (exclusive).

Returns:

the metadata map for the document.

Throws:

IOException

stream

public InputStream stream(long index)
                   throws IOException

Description copied from interface: DocumentCollection

Returns an input stream for the raw content of a document.

Parameters:

index - an index between 0 (inclusive) and DocumentCollection.size() (exclusive).

Returns:

the raw content of the document as an input stream.

Throws:

IOException

factory

public DocumentFactory factory()

Description copied from interface: DocumentSequence

Returns the factory used by this sequence.

Every document sequence is based on a document factory that transforms raw bytes into a sequence of characters. The factory contains useful information such as the number of fields.

Returns:

the factory used by this sequence.