/* * ECatalog is a database front-end, with two main features: * 1. Use of preferences * A preference-based approach, where the user is allowed to define the importance of each criterion. * Then the items are ranked accordingly to his criteria. * 2. Trade-off analysis * A cooperative database approach, where the system "argues" with the user about his criteria. * When there are no matching items, the system explains the minimal conflicting set and * give some possible strong and weak relaxations about his criteria. * This package also containts the software and the set-up details used for our User Study, * comparing the use or not of the two previous features mentioned above. * * Copyright (C) 2006 David Portabella Clotet, Artificial Intelligence Laboratory, EPFL * * This file is part of ecatalog-1.0.zip * * ECatalog is free software and a free user study set-up; * you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * ECatalog is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with ECatalog; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * @version 1.0 * @author David Portabella * To contact the author: * email: david@portabella.name and david.portabella@epfl.ch * * More information about ECatalog: * http://sourceforge.net/projects/ecatalog/ * http://icwww.epfl.ch/~portabel/ecatalogs/ */ package ecatalog.db; import ecatalog.ECatalog; import dpc.utils.SqlUtil; import java.util.Vector; import java.sql.*; import ecatalog.jaxb.ecatalogConfig.ECatalogConfigType; import ecatalog.jaxb.ecatalogConfig.AttributeType; /* An Attribute is a column in the SQL database. * All the distinct values for that column are retrieved in the subclass class of Attribute, typically valuesId[]. * An valueIndex refers to the distinct values, e.g. valueIndex = 2 refers to valuesId[2] * * getValueString(valueIndex = 2) is a function that computes a string for this value, * e.g. for a "Price" attribute, there could be valueId=20, getValueString()="20 CHF". * this script function to compute this string is in the config file * * At any given moment in time, if the solution space is not overconstrained, there is a column in the database * is selected as an example. To get the value for this attribute, call getCurrentExampleValueIndex() */ public abstract class Attribute { protected String id; protected String label; protected int attributeIndex; protected int dbColumnIndex; protected AttributeType config; protected int nbrDistinctValues; protected int currentNbrCompatibleDistinctValues; protected String[] valuesString; protected boolean valueSatisfiesConstraints[]; protected int currentExampleValueIndex; //only valid in a non-overconstrained situation!! protected Database db; public Attribute(AttributeType config, Database db, int attributeIndex) { this.config = config; this.db = db; this.id = config.getId(); this.label = config.getLabel(); this.attributeIndex = attributeIndex; dbColumnIndex = attributeIndex + 1; } public String getId() { return id; } public String getLabel() { return label; } public AttributeType getConfig() { return config; } public int getNbrDistinctValues() { return nbrDistinctValues; } /* Taking into account all user constraints (for all attributes) */ public int getCurrentNbrCompatibleDistinctValues() throws SQLException { if (currentNbrCompatibleDistinctValues == -1) computeCurrentNbrCompatibleDistinctValues(); return currentNbrCompatibleDistinctValues; } /* The value string representation for all the distinct possible values */ public String getValueString(int valueIndex) { return valuesString[valueIndex]; } public int getCurrentExampleValueIndex() { return currentExampleValueIndex; } /* update (or mark to be updated) currentNbrCompatibleDistinctValues, valueSatisfiesConstraints */ public void update() { currentNbrCompatibleDistinctValues = -1; valueSatisfiesConstraints = null; currentExampleValueIndex = -1; } public void updateExample(Item item) throws SQLException { currentExampleValueIndex = getValueIndex(item); } /* Indicates whether a value satisfies all the user constraints (without taking into account the database!) * i.e., valueSatisfiesConstraints[i] is true if valuesId[i] satisfies all the user constraints */ public boolean getValueSatisfiesConstraints(int valueIndex) { if (valueSatisfiesConstraints == null) computeValueSatisfiesConstraints(); return valueSatisfiesConstraints[valueIndex]; } abstract public void init() throws SQLException, Exception; /* Given an item, the function extracts the value from the row (using rs.getXXXX(dbColumnIndex), and gives the index of the value */ public int getValueIndex(Item item) throws SQLException { return item.getValueIndex(attributeIndex); } /* Given a current row from a ResultSet rs, the function extracts the value from the row (using rs.getXXXX(dbColumnIndex), and gives the index of the value */ abstract public int getValueIndex(ResultSet rs) throws SQLException; /* Given a current row from a ResultSet rs, the function extracts the value from the row (using rs.getXXXX(dbColumnIndex), and gives the index of the value */ abstract public int getValueIndex(ResultSet rs, int dbColumnIndex) throws SQLException; /* public String getDbValueString(int valueIndex) { return getDbValueString(valueIndex, true); } */ abstract public String getDbValueString(int valueIndex, boolean quoteIfNecessary); public String getDbValueString(Item item, boolean quoteIfNecessary) throws SQLException { return getDbValueString(getValueIndex(item), quoteIfNecessary); } /* For a given valueIndex, it gets a string corresponding to the equal constraint on this value */ public abstract String getEqualConstraintString(int valueIndex); protected void computeCurrentNbrCompatibleDistinctValues() throws SQLException { ECatalog.lowlevelMsg("EXPENSIVE: " + label + ".computeCurrentNbrCompatibleDistinctValues()"); String query="SELECT COUNT(DISTINCT(" + id + ")) FROM " + db.fromClause + " WHERE " + db.getConstraintsClause(); currentNbrCompatibleDistinctValues = SqlUtil.getUniqueInt(db.executeQuery(query)); } /* It computes valueSatisfiesConstraints[] * This function requieres that db.constraints.updateContext() was called first! */ private void computeValueSatisfiesConstraints() { ECatalog.lowlevelMsg("EXPENSIVE: " + label + ".computeValueSatisfiesConstraints()"); //Selecte the constraints that use this attribute. TODO minor: this could be computed only once at the begining, and each time constraints are added/removed Vector cs = new Vector(); for (Constraint c : db.constraints) { if (!c.areDetailsDefined()) continue; if (c.doesInvolveAttribute(this)) cs.add(c); } valueSatisfiesConstraints = new boolean[nbrDistinctValues]; for (int valueIndex = 0; valueIndex < nbrDistinctValues; valueIndex++) valueSatisfiesConstraints[valueIndex] = computeValueSatisfiesConstraints(cs, valueIndex); } /* This call is expensive, and it is called once by updateConstraintsContext. * This info is later available at valueSatisfiesConstraints * This function requieres that db.constraints.updateContext() was called first! */ private boolean computeValueSatisfiesConstraints(Vector cs, int valueIndex) { for (Constraint c : cs) { if (!c.doesAttributeValueSatisfyConstraint(this, valueIndex)) return false; } return true; } }