it.unimi.di.mg4j.index.cluster
Class DocumentalCluster

java.lang.Object
  it.unimi.di.mg4j.index.Index
      it.unimi.di.mg4j.index.cluster.IndexCluster
          it.unimi.di.mg4j.index.cluster.DocumentalCluster

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

DocumentalConcatenatedCluster, DocumentalMergedCluster

public abstract class DocumentalCluster
extends IndexCluster

A abstract class representing a cluster of local indices containing separate set of documents from the same collection.

This class stores the strategy and possibly the Bloom filters associated with this documental cluster.

Author:

Alessandro Arrabito, Sebastiano Vigna

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class it.unimi.di.mg4j.index.cluster.IndexCluster

IndexCluster.PropertyKeys

Nested classes/interfaces inherited from class it.unimi.di.mg4j.index.Index

Index.EmptyIndexIterator, Index.UriKeys

Field Summary

int[]	allIndices An Array containing the numbers from 0 to the number of local indices (excluded).
boolean	concatenated Whether this documental cluster is concatenated.
static int	DEFAULT_BUFFER_SIZE
boolean	flat Whether this documental cluster is flat; in this case, all local indices have the same term list.
protected DocumentalClusteringStrategy	strategy The clustering strategy.

Fields inherited from class it.unimi.di.mg4j.index.cluster.IndexCluster

BLOOM_EXTENSION, localIndex, STRATEGY_DEFAULT_EXTENSION, termFilter

Fields inherited from class it.unimi.di.mg4j.index.Index

field, hasCounts, hasPayloads, hasPositions, keyIndex, maxCount, numberOfDocuments, numberOfOccurrences, numberOfPostings, numberOfTerms, payload, prefixMap, properties, singletonSet, sizes, termMap, termProcessor

Constructor Summary

DocumentalCluster(Index[] localIndex, DocumentalClusteringStrategy strategy, boolean flat, BloomFilter[] termFilter, int numberOfDocuments, int numberOfTerms, long numberOfPostings, long numberOfOccurences, int maxCount, Payload payload, boolean hasCounts, boolean hasPositions, TermProcessor termProcessor, String field, IntList sizes, Properties properties)
Creates a new documental index cluster.

Method Summary

IndexIterator	documents(CharSequence prefix, int limit) Creates a number of instances of IndexReader for this index and uses them to return a MultiTermIndexIterator over the documents containing any term our of a set of terms defined by a prefix; the prefix is given explicitly, and unless the index has a prefix map, an UnsupportedOperationException will be thrown.
DocumentalClusterIndexReader	getReader(int bufferSize) Creates and returns a new IndexReader based on this index.
String	toString()

Methods inherited from class it.unimi.di.mg4j.index.cluster.IndexCluster

getInstance, keyIndex

Methods inherited from class it.unimi.di.mg4j.index.Index

documents, documents, getEmptyIndexIterator, getEmptyIndexIterator, getEmptyIndexIterator, getEmptyIndexIterator, getInstance, getInstance, getInstance, getInstance, getInstance, getReader, getTermProcessor

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_BUFFER_SIZE

public static final int DEFAULT_BUFFER_SIZE

See Also:

Constant Field Values

concatenated

public final boolean concatenated

Whether this documental cluster is concatenated.

flat

public final boolean flat

Whether this documental cluster is flat; in this case, all local indices have the same term list.

allIndices

public final int[] allIndices

An Array containing the numbers from 0 to the number of local indices (excluded). Used to implement IndexReader.documents(int) more efficiently in flat indices.

strategy

protected final DocumentalClusteringStrategy strategy

The clustering strategy.

Constructor Detail

DocumentalCluster

public DocumentalCluster(Index[] localIndex,
                         DocumentalClusteringStrategy strategy,
                         boolean flat,
                         BloomFilter[] termFilter,
                         int numberOfDocuments,
                         int numberOfTerms,
                         long numberOfPostings,
                         long numberOfOccurences,
                         int maxCount,
                         Payload payload,
                         boolean hasCounts,
                         boolean hasPositions,
                         TermProcessor termProcessor,
                         String field,
                         IntList sizes,
                         Properties properties)

Creates a new documental index cluster.

Method Detail

getReader

public DocumentalClusterIndexReader getReader(int bufferSize)
                                       throws IOException

Description copied from class: Index

Creates and returns a new IndexReader based on this index. After that, you can use the reader to read this index.

Specified by:

getReader in class Index

Parameters:

bufferSize - the size of the buffer to be used accessing the reader, or -1 for a default buffer size.

Returns:

a new IndexReader to read this index.

Throws:

IOException

documents

public IndexIterator documents(CharSequence prefix,
                               int limit)
                        throws IOException,
                               TooManyTermsException

Description copied from class: Index

Creates a number of instances of IndexReader for this index and uses them to return a MultiTermIndexIterator over the documents containing any term our of a set of terms defined by a prefix; the prefix is given explicitly, and unless the index has a prefix map, an UnsupportedOperationException will be thrown.

Overrides:

documents in class Index

Parameters:

prefix - a prefix.

limit - a limit on the number of terms that will be used to resolve the prefix query; if the terms starting with prefix are more than limit, a TooManyTermsException will be thrown.

Throws:

TooManyTermsException - if there are more than limit terms starting with prefix.

IOException

toString

public String toString()

Overrides:

toString in class Object