org.objectweb.cjdbc.controller.cache.metadata
Class MetadataCache

java.lang.Object
  org.objectweb.cjdbc.controller.cache.metadata.MetadataCache

public class MetadataCache

extends java.lang.Object

This class implements a ResultSet metadata cache.

ResultSet Fields are kept here to prevent recomputing them and allocating them each time a query is executed.

Version:

1.0

Author:

Emmanuel Cecchet

Field Summary

private java.util.Hashtable	fieldCache
private static Trace	logger
private int	maxNbOfField
private int	maxNbOfMetadata
private java.util.Hashtable	metadataCache

Constructor Summary

MetadataCache(int maxNbOfMetadata, int maxNbOfField)
Constructor for MetadataCache.

Method Summary

void	addField(java.lang.String fullyQualifiedFieldName, Field field) Add a Field entry to the cache and associate it to the given name.
void	addMetadata(AbstractRequest request, Field[] metadata) Add a metadata entry to the cache and associate it to the given request.
void	flushCache() Flush the cache
Field	getField(java.lang.String fullyQualifiedFieldName) Get the field corresponding to a column name.
Field[]	getMetadata(AbstractRequest request) Get metadata associated to a request.
java.lang.String	getXml() Get xml information about this ParsingCache

Methods inherited from class java.lang.Object

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

Field Detail

logger

private static Trace logger

metadataCache

private java.util.Hashtable metadataCache

fieldCache

private java.util.Hashtable fieldCache

maxNbOfMetadata

private int maxNbOfMetadata

maxNbOfField

private int maxNbOfField

Constructor Detail

MetadataCache

public MetadataCache(int maxNbOfMetadata,
                     int maxNbOfField)

Constructor for MetadataCache.

Parameters:

maxNbOfMetadata - maximum nb of entries in metadata cache

maxNbOfField - maximum nb of entries in field cache

Method Detail

flushCache

public void flushCache()

Flush the cache

getMetadata

public Field[] getMetadata(AbstractRequest request)

Get metadata associated to a request.

Returns null if the cache contains no metadata for the given request.

Parameters:

request - the request we look for

Returns:

the metadata or null if not in cache

addMetadata

public void addMetadata(AbstractRequest request,
                        Field[] metadata)

Add a metadata entry to the cache and associate it to the given request.

Parameters:

request - request to which the metadata belong

metadata - metadata to cache

getField

public Field getField(java.lang.String fullyQualifiedFieldName)

Get the field corresponding to a column name.

Returns null if the cache contains no field for the given name.

Parameters:

fullyQualifiedFieldName - the field name (table.column) to look for

Returns:

the corresponding Field or null if not in cache

addField

public void addField(java.lang.String fullyQualifiedFieldName,
                     Field field)

Add a Field entry to the cache and associate it to the given name.

Parameters:

fullyQualifiedFieldName - table.column name that uniquely identifies the field

field - field to cache

getXml

public java.lang.String getXml()

Get xml information about this ParsingCache

Returns:

String in xml formatted text