Package jade.domain

Class DFDBKB

java.lang.Object

jade.domain.KBManagement.KB

jade.domain.KBManagement.DBKB

jade.domain.DFDBKB

Direct Known Subclasses:

DFHSQLKB

public class DFDBKB
extends DBKB

This class implements a knowledge base used by the DF which stores its content in an external database.

Author:

Elisabetta Cortese - TILab, Roland Mungenast - Profactor

Nested Class Summary

Nested classes/interfaces inherited from class jade.domain.KBManagement.DBKB

DBKB.ConnectionWrapper, DBKB.EmptyKBIterator

Field Summary

Fields

Modifier and Type	Field	Description
protected String	DEFAULT_LONGVARCHAR_TYPE	Default data type for very long strings

Fields inherited from class jade.domain.KBManagement.DBKB

cleanTables, driver

Fields inherited from class jade.domain.KBManagement.KB

lm, logger, sr

Constructor Summary

Constructors

Constructor	Description
DFDBKB(int maxResultLimit, String drv, String url, String user, String passwd, boolean cleanTables)	Constructor

Method Summary

Modifier and Type	Method	Description
protected void	createDFTables()	Creates the proper DB tables.
protected void	createIndices()	Adds explicit indices to the database to speed up queries
protected void	createTable(String name, String[] entries)	Creates a new DB table
protected void	dropDFTables()	Drops all existing DB tables used by the DF.
protected void	dropTable(Statement stmt, String tableName)	Drops a DB table or does nothing if the table doesn't exist.
protected String	getGUID()	Returns a global unique identifier
protected String	getHashValue(Object obj)	Returns an MD5 hash value for an object
protected String	getLongVarCharType()	Returns the name of the SQL type used in the database to represent very long strings.
Enumeration	getSubscriptions()	Return all known subscriptions at the DF
protected void	initConnectionWrapper(DBKB.ConnectionWrapper wrapper)	Subclasses can redefine this method to provide implementation specific ConnectionWrapper initializations
protected Object	insertSingle(Object name, Object fact)	Insert a new DFD object.
protected KBIterator	iteratorSingle(Object template)
protected String	prepDBStr(String s)	This method must be used when inserting text values into a DB.
protected Object	removeSingle(Object name)	Remove the DFD object corresponding to the indicated AID.
protected String	replace(String str, String pattern, String replaceWith)	Replaces all occurences of a pattern in str with replaceWith
protected List	searchSingle(Object template, int maxResult)	Retrieve the DFDs matching the given template
void	setup()	Initializes all used SQL statements, the DB tables and the logging
protected void	subscribeSingle(Object dfd, SubscriptionResponder.Subscription s)
protected boolean	tableExists(String name)	Check whether a database table already exists
protected void	unsubscribeSingle(SubscriptionResponder.Subscription sub)

Methods inherited from class jade.domain.KBManagement.DBKB

createDBConnection, getConnectionWrapper, insert, iterator, remove, search, subscribe, unsubscribe

Methods inherited from class jade.domain.KBManagement.KB

deregister, register, search, setLeaseManager, setSubscriptionResponder

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_LONGVARCHAR_TYPE

protected String DEFAULT_LONGVARCHAR_TYPE

Default data type for very long strings

Constructor Detail

DFDBKB

public DFDBKB(int maxResultLimit,
              String drv,
              String url,
              String user,
              String passwd,
              boolean cleanTables)
       throws SQLException

Constructor

Parameters:

maxResultLimit - internal limit for the number of maximum search results.

drv - database driver

url - database URL

user - database user name

passwd - database password

cleanTables - specifies whether the KB should delete all existing tables for the DF at startup

Throws:

SQLException - an error occured while opening a connection to the database

Method Detail

setup

public void setup()
           throws SQLException

Initializes all used SQL statements, the DB tables and the logging

Specified by:

setup in class DBKB

Throws:

SQLException

initConnectionWrapper

protected void initConnectionWrapper(DBKB.ConnectionWrapper wrapper)
                              throws SQLException

Description copied from class: DBKB

Subclasses can redefine this method to provide implementation specific ConnectionWrapper initializations

Overrides:

initConnectionWrapper in class DBKB

Throws:

SQLException

getLongVarCharType

protected String getLongVarCharType()

Returns the name of the SQL type used in the database to represent very long strings.

getGUID

protected String getGUID()

Returns a global unique identifier

dropTable

protected void dropTable(Statement stmt,
                         String tableName)

Drops a DB table or does nothing if the table doesn't exist.

dropDFTables

protected void dropDFTables()
                     throws SQLException

Drops all existing DB tables used by the DF.

Throws:

SQLException

tableExists

protected boolean tableExists(String name)

Check whether a database table already exists

Parameters:

name - name of the table

createTable

protected void createTable(String name,
                           String[] entries)

Creates a new DB table

Parameters:

name - name of the table

entries - array of column and constraint specifications

Throws:

SQLException - If the table cannot be created

createIndices

protected void createIndices()

Adds explicit indices to the database to speed up queries

createDFTables

protected void createDFTables()

Creates the proper DB tables.

insertSingle

protected Object insertSingle(Object name,
                              Object fact)
                       throws SQLException

Insert a new DFD object.

Specified by:

insertSingle in class DBKB

Returns:

the previous DFD (if any) corresponding to the same AID

Throws:

SQLException

removeSingle

protected Object removeSingle(Object name)
                       throws SQLException

Remove the DFD object corresponding to the indicated AID.

Specified by:

removeSingle in class DBKB

Returns:

the removed DFD (if any)

Throws:

SQLException

searchSingle

protected List searchSingle(Object template,
                            int maxResult)
                     throws SQLException

Retrieve the DFDs matching the given template

Specified by:

searchSingle in class DBKB

Throws:

SQLException

iteratorSingle

protected KBIterator iteratorSingle(Object template)
                             throws SQLException

Specified by:

iteratorSingle in class DBKB

Throws:

SQLException

subscribeSingle

protected void subscribeSingle(Object dfd,
                               SubscriptionResponder.Subscription s)
                        throws SQLException,
                               NotUnderstoodException

Specified by:

subscribeSingle in class DBKB

Throws:

SQLException

NotUnderstoodException

getSubscriptions

public Enumeration getSubscriptions()

Return all known subscriptions at the DF

Specified by:

getSubscriptions in class DBKB

Returns:

Enumeration with instances of the class jade.proto.SubscriptionResponder&Subscription

unsubscribeSingle

protected void unsubscribeSingle(SubscriptionResponder.Subscription sub)
                          throws SQLException

Specified by:

unsubscribeSingle in class DBKB

Throws:

SQLException

getHashValue

protected String getHashValue(Object obj)
                       throws Exception

Returns an MD5 hash value for an object

Parameters:

obj - Object to use for the hash value calcualtion

Returns:

an MD5 value encoded in ISO-8859-1

Throws:

Exception - The hash value couldn't be generated

prepDBStr

protected String prepDBStr(String s)

This method must be used when inserting text values into a DB. It doubles all ' and " characters If the passed parameter is null, then an empty string is returned.

replace

protected String replace(String str,
                         String pattern,
                         String replaceWith)

Replaces all occurences of a pattern in str with replaceWith

Parameters:

str - source string

pattern - pattern string to search for

replaceWith - new string