uk.ac.gla.terrier.structures
Class Index

java.lang.Object
  uk.ac.gla.terrier.structures.Index

All Implemented Interfaces:

Closeable

public class Index
extends java.lang.Object
implements Closeable

This class encapsulates all the Indexes at retrieval time. It is loaded by giving a path and prefix. This looks for an index properties file at path/prefix.properties. Essentially, the properties file then specifies which index structures the index supports. The index then loads these so they can be used in retrieval.

Arbitrary properties can be defined in the index properties files, and in particular, properties are used to record index statistics and the contructor type and values of various index objects. Properties defaults are chosen appropriately for Terrier 1.x indices.

The Index will apply methods on specially marked interfaces. Currently, these are LegacyBitFileStructure and IndexConfigurable. Moreover, structures implementing Closeable will have their close method called when the Index is closed.

Version:

$Revision: 1.35 $

Author:

Craig Macdonald & Vassilis Plachouras

Method Summary

void	addIndexStructure(java.lang.String structureName, java.lang.String className) add an index structure to this index.
void	addIndexStructure(java.lang.String structureName, java.lang.String className, java.lang.String[] paramTypes, java.lang.String[] paramValues) add an index structure to this index.
void	addIndexStructure(java.lang.String structureName, java.lang.String className, java.lang.String paramTypes, java.lang.String paramValues) add an index structure to this index.
void	addIndexStructureInputStream(java.lang.String structureName, java.lang.String className) tell the index about a new input stream index structure it provides.
void	addIndexStructureInputStream(java.lang.String structureName, java.lang.String className, java.lang.String[] paramTypes, java.lang.String[] paramValues) tell the index about a new input stream index structure it provides.
void	addIndexStructureInputStream(java.lang.String structureName, java.lang.String className, java.lang.String paramTypes, java.lang.String paramValues) tell the index about a new input stream index structure it provides.
void	close() Closes the data structures of the index.
static Index	createIndex() Factory method for creating an index.
static Index	createIndex(java.lang.String path, java.lang.String prefix) Factory method for load an index.
static Index	createNewIndex(java.lang.String path, java.lang.String prefix) Factory method create a new index.
static boolean	existsIndex(java.lang.String path, java.lang.String prefix) Returns true if it is likely that an index exists at the specified location
void	flush() Write any dirty data structures down to disk
CollectionStatistics	getCollectionStatistics()
DirectIndex	getDirectIndex() Return the DirectIndex associated with this index
DocumentIndex	getDocumentIndex() Return the DocumentIndex associated with this index
java.lang.String	getIndexProperty(java.lang.String key, java.lang.String defaultValue) get an arbitrary property in the index
java.lang.Object	getIndexStructure(java.lang.String structureName) Obtains the named index structure, using an already loaded one if possible.
java.lang.Object	getIndexStructureInputStream(java.lang.String structureName) Return the input stream associated with the specified structure of this index
int	getIntIndexProperty(java.lang.String key, int defaultValue) get an arbitrary int property from the index
InvertedIndex	getInvertedIndex() Returns the InvertedIndex to use for this index
static java.lang.String	getLastIndexLoadError() Returns the last warning given by an index being loaded.
Lexicon	getLexicon() Return the Lexicon associated with this index
java.lang.String	getPath() Returns the path of this index
java.lang.String	getPrefix() Returns the prefix of this index
boolean	hasIndexStructure(java.lang.String structureName) Does this index have an index structure with the specified name?
boolean	hasIndexStructureInputStream(java.lang.String structureName) Does this index have an index structure input stream with the specified name?
void	setIndexProperty(java.lang.String key, java.lang.String value) set an arbitrary property in the index
java.lang.String	toString() Returns a String representation of this index

Methods inherited from class java.lang.Object

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

Method Detail

hasIndexStructure

public boolean hasIndexStructure(java.lang.String structureName)

Does this index have an index structure with the specified name?

Parameters:

structureName - name of the required structure

Returns:

true if the index has an appropriately named structure

hasIndexStructureInputStream

public boolean hasIndexStructureInputStream(java.lang.String structureName)

Does this index have an index structure input stream with the specified name?

Parameters:

structureName - name of the required structure

Returns:

true if the index has an appropriately named structure

getIndexStructure

public java.lang.Object getIndexStructure(java.lang.String structureName)

Obtains the named index structure, using an already loaded one if possible.

Parameters:

structureName - name of the required structure

Returns:

desired object or null if not found

getIndexStructureInputStream

public java.lang.Object getIndexStructureInputStream(java.lang.String structureName)

Return the input stream associated with the specified structure of this index

Parameters:

structureName - The name of the structure of which you want the inputstream. Eg "lexicon"

Returns:

Required structure, or null if not found

close

public void close()

Closes the data structures of the index.

Specified by:

close in interface Closeable

flush

public void flush()

Write any dirty data structures down to disk

getInvertedIndex

public InvertedIndex getInvertedIndex()

Returns the InvertedIndex to use for this index

getDirectIndex

public DirectIndex getDirectIndex()

Return the DirectIndex associated with this index

getLexicon

public Lexicon getLexicon()

Return the Lexicon associated with this index

getDocumentIndex

public DocumentIndex getDocumentIndex()

Return the DocumentIndex associated with this index

getCollectionStatistics

public CollectionStatistics getCollectionStatistics()

toString

public java.lang.String toString()

Returns a String representation of this index

Overrides:

toString in class java.lang.Object

getPath

public java.lang.String getPath()

Returns the path of this index

getPrefix

public java.lang.String getPrefix()

Returns the prefix of this index

addIndexStructure

public void addIndexStructure(java.lang.String structureName,
                              java.lang.String className)

add an index structure to this index. Structure will be called structureName, and instantiated by a class called className. Instantiation parameters are "String,String", which are "path,prefix".

Parameters:

structureName -

className -

addIndexStructure

public void addIndexStructure(java.lang.String structureName,
                              java.lang.String className,
                              java.lang.String[] paramTypes,
                              java.lang.String[] paramValues)

add an index structure to this index. Structure will be called structureName, and instantiated by a class called className. Instantiation type parameters or values are non-default.

addIndexStructure

public void addIndexStructure(java.lang.String structureName,
                              java.lang.String className,
                              java.lang.String paramTypes,
                              java.lang.String paramValues)

add an index structure to this index. Structure will be called structureName, and instantiated by a class called className. Instantiation type parameters or values are non-default.

addIndexStructureInputStream

public void addIndexStructureInputStream(java.lang.String structureName,
                                         java.lang.String className)

tell the index about a new input stream index structure it provides.

addIndexStructureInputStream

public void addIndexStructureInputStream(java.lang.String structureName,
                                         java.lang.String className,
                                         java.lang.String[] paramTypes,
                                         java.lang.String[] paramValues)

tell the index about a new input stream index structure it provides.

addIndexStructureInputStream

public void addIndexStructureInputStream(java.lang.String structureName,
                                         java.lang.String className,
                                         java.lang.String paramTypes,
                                         java.lang.String paramValues)

tell the index about a new input stream index structure it provides.

setIndexProperty

public void setIndexProperty(java.lang.String key,
                             java.lang.String value)

set an arbitrary property in the index

Parameters:

key - Key to of the property to set

value - Value of the property to set

getIndexProperty

public java.lang.String getIndexProperty(java.lang.String key,
                                         java.lang.String defaultValue)

get an arbitrary property in the index

Parameters:

key - Key of the property to get

defaultValue - value of the property to use if property is not set

Returns:

Value of the property

getIntIndexProperty

public int getIntIndexProperty(java.lang.String key,
                               int defaultValue)

get an arbitrary int property from the index

createIndex

public static Index createIndex(java.lang.String path,
                                java.lang.String prefix)

Factory method for load an index. This method should be used in order to load an existing index in the applications.

Parameters:

path - String the path in which the data structures will be created.

prefix - String the prefix of the files to be created.

createNewIndex

public static Index createNewIndex(java.lang.String path,
                                   java.lang.String prefix)

Factory method create a new index. This method should be used in order to load a new index in the applications.

Parameters:

path - String the path in which the data structures will be created.

prefix - String the prefix of the files to be created.

getLastIndexLoadError

public static java.lang.String getLastIndexLoadError()

Returns the last warning given by an index being loaded.

existsIndex

public static boolean existsIndex(java.lang.String path,
                                  java.lang.String prefix)

Returns true if it is likely that an index exists at the specified location

Parameters:

path -

prefix -

Returns:

true if a .properties or a .log files exists

createIndex

public static Index createIndex()

Factory method for creating an index. This method should be used in order to load an existing index in the applications.