weka.associations.AssociationRule.java Source code

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Here is the source code for weka.associations.AssociationRule.java

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/*
 *   This program is free software: 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 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *    AssociationRule.java
 *    Copyright (C) 2010-2012 University of Waikato, Hamilton, New Zealand
 *
 */

package weka.associations;

import java.util.ArrayList;
import java.util.Collection;

/**
 * Abstract class for storing and manipulating an association rule.
 * 
 * @author Mark Hall (mhall{[at]}pentaho{[dot]}com).
 * @version $Revision$
 */
public abstract class AssociationRule implements Comparable<AssociationRule> {

    /**
     * Get the premise of this rule.
     * 
     * @return the premise of this rule.
     */
    public abstract Collection<Item> getPremise();

    /**
     * Get the consequence of this rule.
     * 
     * @return the consequence of this rule.
     */
    public abstract Collection<Item> getConsequence();

    /**
     * Get the name of the primary metric of this rule (e.g. confidence).
     * 
     * @return the name of the primary metric of this rule.
     */
    public abstract String getPrimaryMetricName();

    /**
     * Get the value of the metric for this rule. 
     * 
     * @return the value of the metric for this rule.
     */
    public abstract double getPrimaryMetricValue();

    /**
     * Get the value of the named metric for this rule
     * 
     * @param metricName the metric to get the value for
     * @return the value of the named metric
     * @throws Exception if the requested metric is unknown for this rule
     */
    public abstract double getNamedMetricValue(String metricName) throws Exception;

    /**
     * Gets the number of metrics available for this rule.
     * 
     * @return the number of metrics available for this rule
     */
    public abstract int getNumberOfMetricsForRule();

    /**
     * Return the names of the metrics available for this rule.
     * 
     * @return the names of the metrics that are available for this rule.
     */
    public abstract String[] getMetricNamesForRule();

    /**
     * Get all the available metric values for this rule. Values are
     * returned in an array with entries that correspond to the metric
     * names returned by getMetricNamesForRule().
     * 
     * @return all the available metrics for this rule.
     * @throws Exception if a metric can't be computed for some reason.
     */
    public abstract double[] getMetricValuesForRule() throws Exception;

    /**
     * Get the support for the premise.
     * 
     * @return the support for the premise.
     */
    public abstract int getPremiseSupport();

    /**
     * Get the support for the consequence.
     * 
     * @return the support for the consequence.
     */
    public abstract int getConsequenceSupport();

    /**
     * Get the total support for this rule (premise + consequence).
     * 
     * @return the total support for this rule.
     */
    public abstract int getTotalSupport();

    /**
     * Get the total number of transactions in the data.
     * 
     * @return the total number of transactions in the data.
     */
    public abstract int getTotalTransactions();

    /**
     * Compare this rule to the supplied rule.
     * 
     * @param other the rule to compare to.
     * @return the result of the comparison.
     */
    public int compareTo(AssociationRule other) {
        return -Double.compare(getPrimaryMetricValue(), other.getPrimaryMetricValue());
    }

    /**
     * Return true if this rule is equal to the supplied one.
     * 
     * @return true if this rule is the same as the supplied rule.
     */
    public boolean equals(Object other) {
        if (!(other instanceof AssociationRule)) {
            return false;
        }

        AssociationRule otherRule = (AssociationRule) other;
        boolean result = getPremise().equals(otherRule.getPremise())
                && getConsequence().equals(otherRule.getConsequence())
                && (getPrimaryMetricValue() == otherRule.getPrimaryMetricValue());

        return result;
    }

    public boolean containsItems(ArrayList<Item> items, boolean useOr) {
        int numItems = items.size();
        int count = 0;

        for (Item i : getPremise()) {
            if (items.contains(i)) {
                if (useOr) {
                    return true; // can stop here
                } else {
                    count++;
                }
            }
        }

        for (Item i : getConsequence()) {
            if (items.contains(i)) {
                if (useOr) {
                    return true; // can stop here
                } else {
                    count++;
                }
            }
        }

        if (!useOr) {
            if (count == numItems) {
                return true;
            }
        }

        return false;
    }
}