uk.ac.ic.doc.rodex.qproc
Class QueryMediator

java.lang.Object
  uk.ac.ic.doc.rodex.qproc.QueryMediator

All Implemented Interfaces:

IQueryMediator

public class QueryMediator
extends java.lang.Object
implements IQueryMediator

QueryMediator.java This class is the interface to the query processing and execution engine. Its job is to cordinate different components to execute user queries (local and P2P)

Author:

Duc M Le dmle@doc.ic.ac.uk Created on April 5, 2006 Department of Computing, Imperial College

Field Summary

static int	LANG_STANDARD
static int	LANG_XQUERY

Method Summary

java.lang.String	getDebugInf() Debug information
java.lang.String	getDebugResult() Debug result
java.lang.String	getExternalQuery() Getter methods for various query (ASG) objects
java.lang.String	getFormulatedQuery()
java.lang.String	getLogicalOptimisedQuery()
static QueryMediator	getMediatorInstance() Create a singleton mediator object
java.lang.String	getPhysicalOptimisedQuery()
java.lang.String	getProcessedQuery()
void	getSODefinition(QuerySubGoal qsg) Get query definitions for a schema object.
java.util.List	performQuery(QueryDescription qd, Schema srcSchema, Schema[] targetSchemas) Overloading method to perform a query given only the name of the public schema
java.util.List	performQuery(QueryDescription qd, java.lang.String schemaName)

Methods inherited from class java.lang.Object

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

Field Detail

LANG_STANDARD

public static final int LANG_STANDARD

See Also:

Constant Field Values

LANG_XQUERY

public static final int LANG_XQUERY

See Also:

Constant Field Values

Method Detail

getMediatorInstance

public static QueryMediator getMediatorInstance()

Create a singleton mediator object

performQuery

public java.util.List performQuery(QueryDescription qd,
                                   java.lang.String schemaName)
                            throws QueryProcessingException,
                                   AutoMedException

Throws:

QueryProcessingException

AutoMedException

performQuery

public java.util.List performQuery(QueryDescription qd,
                                   Schema srcSchema,
                                   Schema[] targetSchemas)
                            throws QueryProcessingException,
                                   AutoMedException

Overloading method to perform a query given only the name of the public schema

Parameters:

qd - the QueryDescription object

useCache - boolean value to indicate whether or not to use cache for rewriting

optimisedQuery - boolean value to optimise query or not

rewriteQuery - boolean value to rewrite query or not

lang - query language type used

srcSchema - the Schema upon which the query is posted

targetSchemas - an array of data-source Schemas to which query is actually sent for execution. Note that targetSchemas is a subset of the actual data sources of srcSchema

Returns:

List the query result

Throws:

QueryProcessingException

AutoMedException

getSODefinition

public void getSODefinition(QuerySubGoal qsg)
                     throws IntegrityException,
                            DataSourceException

Get query definitions for a schema object. This method basically extracts the schema from the qsg argument, retrieves the associated Schema object, retrieves the associated AutoMedWrapper object to this schema and invoke the AutoMedWrapper.getSODefinition() method to do do the job

Throws:

IntegrityException

DataSourceException

getExternalQuery

public java.lang.String getExternalQuery()

Getter methods for various query (ASG) objects

getFormulatedQuery

public java.lang.String getFormulatedQuery()

getProcessedQuery

public java.lang.String getProcessedQuery()

getLogicalOptimisedQuery

public java.lang.String getLogicalOptimisedQuery()

getPhysicalOptimisedQuery

public java.lang.String getPhysicalOptimisedQuery()

getDebugInf

public java.lang.String getDebugInf()

Debug information

getDebugResult

public java.lang.String getDebugResult()

Debug result