it.unimi.di.mg4j.document
Class ConcatenatedDocumentCollection

java.lang.Object
  it.unimi.di.mg4j.document.AbstractDocumentSequence
      it.unimi.di.mg4j.document.AbstractDocumentCollection
          it.unimi.di.mg4j.document.ConcatenatedDocumentCollection

All Implemented Interfaces:

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

public class ConcatenatedDocumentCollection
extends AbstractDocumentCollection
implements Serializable

A document collection exhibiting a list of underlying document collections, called segments, as a single collection. The underlying collections are (virtually) concatenated—that is, the first document of the second collection is renumbered to the size of the first collection, and so on. All underlying collections must use the same factory class.

Author:

Sebastiano Vigna

See Also:

Serialized Form

Nested Class Summary

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

AbstractDocumentCollection.PropertyKeys

Field Summary

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

DEFAULT_EXTENSION

Constructor Summary

	ConcatenatedDocumentCollection(String... collectionName) Creates a new, partially uninitialised concatenated document collection using giving component collections names.
protected	ConcatenatedDocumentCollection(String[] collectionName, DocumentCollection[] collection) Creates a new concatenated document collection using giving component collections.

Method Summary

void	close() Closes this document sequence, releasing all resources.
DocumentCollection	copy()
Document	document(int index) Returns the document given its index.
DocumentFactory	factory() Returns the factory used by this sequence.
void	filename(CharSequence filename) Does nothing.
Reference2ObjectMap<Enum<?>,Object>	metadata(int index) Returns the metadata map for a document.
int	size() Returns the number of documents in this collection.
InputStream	stream(int index) Returns an input stream for the raw content of a document.

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

ensureDocumentIndex, iterator, main, printAllDocuments, toString

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

finalize, load

Methods inherited from class java.lang.Object

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

Constructor Detail

ConcatenatedDocumentCollection

protected ConcatenatedDocumentCollection(String[] collectionName,
                                         DocumentCollection[] collection)

Creates a new concatenated document collection using giving component collections.

Parameters:

collection - a list of component collections.

ConcatenatedDocumentCollection

public ConcatenatedDocumentCollection(String... collectionName)
                               throws IllegalArgumentException,
                                      SecurityException

Creates a new, partially uninitialised concatenated document collection using giving component collections names.

Parameters:

collectionName - a list of names of component collections.

Throws:

IllegalArgumentException

SecurityException

Method Detail

filename

public void filename(CharSequence filename)

Description copied from class: AbstractDocumentSequence

Does nothing.

Specified by:

filename in interface DocumentSequence

Overrides:

filename in class AbstractDocumentSequence

Parameters:

filename - the filename of this document sequence.

copy

public DocumentCollection copy()

Specified by:

copy in interface DocumentCollection

Specified by:

copy in interface FlyweightPrototype<DocumentCollection>

document

public Document document(int index)
                  throws IOException

Description copied from interface: DocumentCollection

Returns the document given its index.

Specified by:

document in interface DocumentCollection

Parameters:

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

Returns:

the index-th document.

Throws:

IOException

metadata

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

Description copied from interface: DocumentCollection

Returns the metadata map for a document.

Specified by:

metadata in interface DocumentCollection

Parameters:

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

Returns:

the metadata map for the document.

Throws:

IOException

size

public int size()

Description copied from interface: DocumentCollection

Returns the number of documents in this collection.

Specified by:

size in interface DocumentCollection

Returns:

the number of documents in this collection.

stream

public InputStream stream(int index)
                   throws IOException

Description copied from interface: DocumentCollection

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

Specified by:

stream in interface DocumentCollection

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.

Specified by:

factory in interface DocumentSequence

Returns:

the factory used by this sequence.

close

public void close()
           throws IOException

Description copied from interface: DocumentSequence

Closes this document sequence, releasing all resources.

You should always call this method after having finished with this document sequence. Implementations are invited to call this method in a finaliser as a safety net (even better, implement SafelyCloseable), but since there is no guarantee as to when finalisers are invoked, you should not depend on this behaviour.

Specified by:

close in interface DocumentSequence

Specified by:

close in interface Closeable

Overrides:

close in class AbstractDocumentSequence

Throws:

IOException