uk.ac.bbk.dcs.automed.qproc.reformulate
Class QueryReformulator

java.lang.Object
  uk.ac.bbk.dcs.automed.qproc.reformulate.QueryReformulator

All Implemented Interfaces:

QueryReformulationProvider

public class QueryReformulator
extends java.lang.Object
implements QueryReformulationProvider

Responsible for reformulating a query along AutoMed pathways (GAV, LAV or BAV). Reformulation logic is the same irrespective of the reformulation technique(GAV, BAV, LAV). This is because the functionality to create composite views takes care of providing the correct set of views to the reformulation class. Query reformulator is constructed as an empty instance. When using the reformulate() method, the source schema, target schema and the query processor configuration is provided. Because of caching of composite and atomics views at lower levels, its very cheap to have any number of instances of this class and just use reformulate method whenever needed.

Author:

Sandeep Mittal, Lucas Zamboulis

Field Summary

protected java.util.logging.Logger	_logger
protected java.lang.String	_schemaPrefix
protected QueryProcessorConfiguration	originalQpc

Constructor Summary

QueryReformulator()
Constructs an instance of this class.

Method Summary

private void	changeCollectionSemantics(Cell c, java.lang.String desiredColType)
private void	convertQueryToTargets(Cell qc, Schema source, Schema[] targets, java.lang.String integrationSemantics, QueryProcessorConfiguration qpc)
protected void	convertSchemeToTarget(Cell n, Schema source, Schema[] targets, java.lang.String integrationSemantics, QueryProcessorConfiguration qpc)
private java.lang.String	createIdQueryString(java.lang.String integrationSemantics, Schema[] targets)
private CompositeViewMap	getCompositeViewMap(Schema source, Schema target, QueryProcessorConfiguration qpc)
private Schema	getDualModelDataSource(Schema target)
private java.lang.String	getIdSemanticsFromPathways(Schema source, Schema[] targets)
private Cell	getTargetsIdSemantics(java.lang.String integrationSemantics, Schema source, Schema[] targets) Semantics of how to combine the results from data sources.
static void	main(java.lang.String[] args)
protected void	o(java.lang.Object s)
protected void	o(java.lang.Object s, java.util.logging.Level logLevel) Logging functionality
void	reformulate(ASG query, Schema source, Schema[] targets, java.lang.String integrationSemantics, QueryProcessorConfiguration qpc) Reformulate an IQL query based on a given configuration
protected void	reformulateInternal(Cell query, Schema source, Schema[] targets, java.lang.String integrationSemantics, QueryProcessorConfiguration qpc)
private void	replaceIdGraph(Cell idc, java.util.Map finalViewMap)

Methods inherited from class java.lang.Object

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

Field Detail

_schemaPrefix

protected final java.lang.String _schemaPrefix

See Also:

Constant Field Values

_logger

protected java.util.logging.Logger _logger

originalQpc

protected QueryProcessorConfiguration originalQpc

Constructor Detail

QueryReformulator

public QueryReformulator()

Constructs an instance of this class.

Method Detail

reformulate

public void reformulate(ASG query,
                        Schema source,
                        Schema[] targets,
                        java.lang.String integrationSemantics,
                        QueryProcessorConfiguration qpc)
                 throws QueryReformulationException

Description copied from interface: QueryReformulationProvider

Reformulate an IQL query based on a given configuration

Specified by:

reformulate in interface QueryReformulationProvider

Parameters:

query - an ASG object of an IQL query

integrationSemantics - Semantics of how to combine results from various target databases.

qpc - a {@link QueryProcessingConfiguration) object specific for query reformulation

Throws:

QueryReformulationException

reformulateInternal

protected void reformulateInternal(Cell query,
                                   Schema source,
                                   Schema[] targets,
                                   java.lang.String integrationSemantics,
                                   QueryProcessorConfiguration qpc)
                            throws QueryReformulationException

Throws:

QueryReformulationException

convertQueryToTargets

private void convertQueryToTargets(Cell qc,
                                   Schema source,
                                   Schema[] targets,
                                   java.lang.String integrationSemantics,
                                   QueryProcessorConfiguration qpc)
                            throws QueryReformulationException

Throws:

QueryReformulationException

convertSchemeToTarget

protected void convertSchemeToTarget(Cell n,
                                     Schema source,
                                     Schema[] targets,
                                     java.lang.String integrationSemantics,
                                     QueryProcessorConfiguration qpc)
                              throws QueryReformulationException

Throws:

QueryReformulationException

getDualModelDataSource

private Schema getDualModelDataSource(Schema target)

getCompositeViewMap

private CompositeViewMap getCompositeViewMap(Schema source,
                                             Schema target,
                                             QueryProcessorConfiguration qpc)
                                      throws QueryReformulationException

Throws:

QueryReformulationException

replaceIdGraph

private void replaceIdGraph(Cell idc,
                            java.util.Map finalViewMap)
                     throws QueryReformulationException

Throws:

QueryReformulationException

getTargetsIdSemantics

private Cell getTargetsIdSemantics(java.lang.String integrationSemantics,
                                   Schema source,
                                   Schema[] targets)
                            throws QueryReformulationException

Semantics of how to combine the results from data sources. Given a set of data sources, e.g. DS1 , DS2 and DS3 , a user has the following ways of specifying the integration semantics to an instance of GQP:

• Shorthand: The following four integration operators can be used as a shorthand notation to specify a generic integration semantics for all the target data sources, without specifying the names of the data sources. The GQP combines the results of all the target data sources using the same operator in the order the target data sources are specified in the input target data source array.
  • Choose semantics: values coming from one data source are returned (choose DS1 DS2 ); which data source is chosen depends on the ChooseOptimiser (Section 3.6) or, if the ChooseOptimiser is not used, the choose IQL function (Appendix A).
  • Append semantics: all values from all data sources are returned ((++) DS1 DS2 ).
  • Intersect semantics: a value is returned only if it is present in all data sources ((intersect) DS1 DS2 ).
  • Union semantics: a value is returned if it is present in any data source (distinct ((++) DS1 DS2)).
• Verbose: In verbose form, a user must specify an expression containing the names of each of the target datasources and joined together using any the operators described above or any of the set operators, such as, -- (monus). Data source name must be prefixed by a $ symbol. For example, integration semantics can be as simple as DS1 ++ DS2 ++ DS3 or arbitrarily complex, e.g. (DS1 intersect DS2 ) ++ (DS1 -- DS2)

Throws:

QueryReformulationException

createIdQueryString

private java.lang.String createIdQueryString(java.lang.String integrationSemantics,
                                             Schema[] targets)

getIdSemanticsFromPathways

private java.lang.String getIdSemanticsFromPathways(Schema source,
                                                    Schema[] targets)

changeCollectionSemantics

private void changeCollectionSemantics(Cell c,
                                       java.lang.String desiredColType)

o

protected void o(java.lang.Object s,
                 java.util.logging.Level logLevel)

Logging functionality

Parameters:

s -

logLevel -

o

protected void o(java.lang.Object s)

main

public static void main(java.lang.String[] args)
                 throws java.lang.Exception

Throws:

java.lang.Exception