org.terrier.realtime.memory

Class MemoryMetaIndex

java.lang.Object

org.terrier.structures.indexing.MetaIndexBuilder

org.terrier.realtime.memory.MemoryMetaIndex

All Implemented Interfaces:

Closeable, Serializable, AutoCloseable, MetaIndex

Direct Known Subclasses:

MemoryCompressedMetaIndex, MemoryMetaIndexMap

public class MemoryMetaIndex
extends MetaIndexBuilder
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.compressed.crop.long - 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, Craig Macdonald

See Also:

Serialized Form

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method and Description
void	close() Delete contents of metadata index (but keep the configured keys).
String[]	getAllItems(int docid) Obtain all metadata for specified document.
int	getDocument(String key, String value) Obtain docid where document has specified metadata value in the specified type.
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
String[]	getReverseKeys() Returns the reverse 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

Constructor Detail

MemoryMetaIndex

public MemoryMetaIndex()

MemoryMetaIndex

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

MemoryMetaIndex

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

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)

Write meta-data for document.

Specified by:

writeDocumentEntry in class MetaIndexBuilder

writeDocumentEntry

public void writeDocumentEntry(String[] data)

This method has been made public for creating

Specified by:

writeDocumentEntry in class MetaIndexBuilder

Parameters:

data -

getDocument

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

Description copied from interface: MetaIndex

Obtain docid where document has specified metadata value in the specified type. Returns -1 if the value cannot be found for the specified key type.

Specified by:

getDocument in interface MetaIndex

Throws:

IOException

getReverseKeys

public String[] getReverseKeys()

Description copied from interface: MetaIndex

Returns the reverse keys of this meta index

Specified by:

getReverseKeys in interface MetaIndex

close

public void close()
           throws IOException

Delete contents of metadata index (but keep the configured 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()