org.terrier.realtime.memory

Class MemoryMetaIndex

java.lang.Object

org.terrier.realtime.memory.MemoryMetaIndex

All Implemented Interfaces:

Closeable, Serializable, AutoCloseable, MetaIndex

Direct Known Subclasses:

MemoryCompressedMetaIndex, MemoryMetaIndexMap

public class MemoryMetaIndex
extends Object
implements MetaIndex, Serializable

An in-memory version of a Meta-data index. It stores additional information about each document, e.g. the docno or title. Access to the memory versions of the meta index are faster than the on-disk versions, but can use up large amounts of RAM to store.

Properties

• indexer.meta.forward.keys - key names to store in the meta index
• indexer.meta.forward.keylens - max key lengths for keys to store (this is ignored unless metaindex.crop is set)
• metaindex.crop - should the content to store be cropped down to the length specified in indexer.meta.forward.keylens?

Since:

4.0

Author:

Richard McCreadie, Stuart Mackie

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
String[]	keylens
String[]	keys
static String[]	reverse

Constructor Summary

Constructors

Constructor and Description
MemoryMetaIndex() Constructor.
MemoryMetaIndex(String[] metaKeys, int[] metaLengths) Constructor.

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Delete contents of metadata index (but keep keys).
String[]	getAllItems(int docid) Obtain all metadata for specified document.
int	getDocument(String key, String value) Not implemented.
String	getItem(String key, int docid) Obtain metadata of specified type for specified document.
String[]	getItems(String[] keys, int docid) Obtain metadata of specified types for specified document.
String[][]	getItems(String[] keys, int[] docids) Obtain metadata of specified types for specified documents.
String[]	getItems(String key, int[] docids) Obtain metadata of specified type for specified documents.
int[]	getKeyLengths()
String[]	getKeys() Returns the keys of this meta index
Iterator<String[]>	iterator() Return iterator over meta-data index.
void	writeDocumentEntry(Map<String,String> data) Write meta-data for document.
void	writeDocumentEntry(String[] data) This method has been made public for creating

Methods inherited from class java.lang.Object

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

Field Detail

reverse

public static String[] reverse

keys

public String[] keys

keylens

public String[] keylens

Constructor Detail

MemoryMetaIndex

public MemoryMetaIndex(String[] metaKeys,
               int[] metaLengths)

Constructor.

MemoryMetaIndex

public MemoryMetaIndex()

Constructor.

Method Detail

getKeys

public String[] getKeys()

Returns the keys of this meta index

Specified by:

getKeys in interface MetaIndex

getItem

public String getItem(String key,
             int docid)
               throws IOException

Obtain metadata of specified type for specified document.

Specified by:

getItem in interface MetaIndex

Throws:

IOException

getAllItems

public String[] getAllItems(int docid)
                     throws IOException

Obtain all metadata for specified document.

Specified by:

getAllItems in interface MetaIndex

Throws:

IOException

getItems

public String[] getItems(String key,
                int[] docids)
                  throws IOException

Obtain metadata of specified type for specified documents.

Specified by:

getItems in interface MetaIndex

Throws:

IOException

getItems

public String[] getItems(String[] keys,
                int docid)
                  throws IOException

Obtain metadata of specified types for specified document.

Specified by:

getItems in interface MetaIndex

Throws:

IOException

getItems

public String[][] getItems(String[] keys,
                  int[] docids)
                    throws IOException

Obtain metadata of specified types for specified documents.

Specified by:

getItems in interface MetaIndex

Throws:

IOException

writeDocumentEntry

public void writeDocumentEntry(Map<String,String> data)
                        throws Exception

Write meta-data for document.

Throws:

Exception

writeDocumentEntry

public void writeDocumentEntry(String[] data)

This method has been made public for creating

Parameters:

data -

getDocument

public int getDocument(String key,
              String value)
                throws IOException

Not implemented.

Specified by:

getDocument in interface MetaIndex

Throws:

IOException

close

public void close()
           throws IOException

Delete contents of metadata index (but keep keys).

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException

iterator

public Iterator<String[]> iterator()

Return iterator over meta-data index.

getKeyLengths

public int[] getKeyLengths()