uk.ac.ic.doc.automed.wrappers
Class CSVWrapper

java.lang.Object
  uk.ac.ic.doc.automed.wrappers.AutoMedWrapper
      uk.ac.ic.doc.automed.wrappers.CSVWrapper

public class CSVWrapper
extends AutoMedWrapper

Author:

Andrew Charles Smith - acs203 This class provides methods to wrap an CSV file

Field Summary

static java.lang.String

driverString

Fields inherited from class uk.ac.ic.doc.automed.wrappers.AutoMedWrapper

am, awf, debug, driver, emptyKeyProtection, emptyKeys, optionKeyProtection, optionKeys, password, protocol, s, url, username

Constructor Summary

CSVWrapper()
Creates a new, empty instance of XMLSchemaWrapper

CSVWrapper(AccessMethod am, java.lang.String password)
This constructor is used when querying the schema

Method Summary

protected void	connect() Check that the CSV file exists
ASG	executeCSVQuery(ASG ASGquery) Given an IQL query, this method queries the CSV file, then returns the answer in ASG format.
ASG	executeIQL(ASG q) Execute an IQL query on the datasource.
AutoMedWrapperFactory	getAutoMedWrapperFactory() Return the AutoMedWrapperFactory currently associated with this wrapper.
protected AutoMedWrapperFactory	getDefaultWrapperFactory() Return the default AutoMedWrapperFactory that is used to generate Schema instances from information in a data sources
static java.lang.String	getDriver() The name of the driver string that identifies this wrapper
java.lang.String	getProtocolName() The name of the Protocol that this wrapper uses
void	getSODefinition(QuerySubGoal qsg) Implement AutoMedWrapper abstract method This method should never be executed because the calling method should already know that the transformation leading to the schema object represented by qsg variable belongs to a source schema.
java.lang.String	getUri() Return the url for this wrapper
boolean	insertIQL(ASG aSG) Execute an IQL insert on the datasource.

Methods inherited from class uk.ac.ic.doc.automed.wrappers.AutoMedWrapper

atDebugLevel, cacheWrapper, deleteIQL, executeIQL, executeLocalQuery, getAccessMethod, getAutoMedWrapper, getAutoMedWrapper, getDrivers, getOption, getOptionKeyProtection, getOptionKeys, getProtocol, getQueryCache, getQueryCache, getQueryParser, getSchema, getSchema, getSODefinition, newAutoMedSchema, newAutoMedWrapper, newAutoMedWrapper, newAutoMedWrapper, registerWrapper, selectNewAutoMedWrapper, selectNewAutoMedWrapper, setDebugLevel, setOption, updateCache

Methods inherited from class java.lang.Object

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

Field Detail

driverString

public static final java.lang.String driverString

See Also:

Constant Field Values

Constructor Detail

CSVWrapper

public CSVWrapper()

Creates a new, empty instance of XMLSchemaWrapper

CSVWrapper

public CSVWrapper(AccessMethod am,
                  java.lang.String password)
           throws DataSourceException,
                  NotFoundException

This constructor is used when querying the schema

Throws:

DataSourceException

NotFoundException

Method Detail

getUri

public java.lang.String getUri()

Return the url for this wrapper

Returns:

the url

connect

protected void connect()
                throws DataSourceException

Check that the CSV file exists

Specified by:

connect in class AutoMedWrapper

Throws:

DataSourceException - if unable to connect to the data source

executeIQL

public ASG executeIQL(ASG q)
               throws DataSourceException

Description copied from class: AutoMedWrapper

Execute an IQL query on the datasource.

Specified by:

executeIQL in class AutoMedWrapper

Parameters:

q - An IQL query held in an ASG which complies with the limitations of what this wrapper is able to process

Returns:

An ASG containing the results of the query

Throws:

DataSourceException

executeCSVQuery

public ASG executeCSVQuery(ASG ASGquery)
                    throws DataSourceException

Given an IQL query, this method queries the CSV file, then returns the answer in ASG format.

Parameters:

ASGquery - the IQL query in ASG format

Returns:

the answer to the IQL query in ASG format

Throws:

DataSourceException

getDriver

public static java.lang.String getDriver()

The name of the driver string that identifies this wrapper

getAutoMedWrapperFactory

public AutoMedWrapperFactory getAutoMedWrapperFactory()

Description copied from class: AutoMedWrapper

Return the AutoMedWrapperFactory currently associated with this wrapper.

Overrides:

getAutoMedWrapperFactory in class AutoMedWrapper

getDefaultWrapperFactory

protected AutoMedWrapperFactory getDefaultWrapperFactory()

Description copied from class: AutoMedWrapper

Return the default AutoMedWrapperFactory that is used to generate Schema instances from information in a data sources

Specified by:

getDefaultWrapperFactory in class AutoMedWrapper

getProtocolName

public java.lang.String getProtocolName()

Description copied from class: AutoMedWrapper

The name of the Protocol that this wrapper uses

Specified by:

getProtocolName in class AutoMedWrapper

insertIQL

public boolean insertIQL(ASG aSG)

Description copied from class: AutoMedWrapper

Execute an IQL insert on the datasource. Note that in later releases this method will become abstract, but at present no Wrapper implements this method.

Overrides:

insertIQL in class AutoMedWrapper

Parameters:

aSG - is the ASG representation of an IQL query of the form

sub [t1, ..., tn] s

where:

• 'sub' is the sub-bag builtin function (this has the same semantics as sub-set if operating on sets, which is what the extents of schemes are)
• [t1, ..., tn] are the tuples to be inserted/deleted
• s is the scheme that they will be inserted into/deleted from

The semantics and execution of the insert request will depend on the data source e.g. for a relational database it could be translated into a series of INSERT requests within a single transaction, which may fail or succeeed as a whole (and thus return False or True respectively from the insertIQL method). For a non-transactional repository like the HDM or XML flat files, we may choose to allow partial updates e.g. some of a set of tuples are inserted, while some already exist or violate some constraint or another.

getSODefinition

public void getSODefinition(QuerySubGoal qsg)
                     throws DataSourceException

Implement AutoMedWrapper abstract method This method should never be executed because the calling method should already know that the transformation leading to the schema object represented by qsg variable belongs to a source schema.

Specified by:

getSODefinition in class AutoMedWrapper

Throws:

DataSourceException