ThresholdEvaluatorAbsoluteChange.java

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 * Copyright (C) 2008-2011 The OpenNMS Group, Inc.
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package org.opennms.netmgt.threshd;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.opennms.netmgt.EventConstants;
import org.opennms.netmgt.xml.event.Event;
import org.springframework.util.Assert;

/**
 * Implements an absolute change threshold check.  If the value changes by more than the specified amount
 * then it will trigger.  As for relative change, re-arm and trigger are unused
 *
 * @author ranger
 * @version $Id: $
 */
public class ThresholdEvaluatorAbsoluteChange implements ThresholdEvaluator {
    
    private static final String TYPE = "absoluteChange";

    /** {@inheritDoc} */
    public ThresholdEvaluatorState getThresholdEvaluatorState(BaseThresholdDefConfigWrapper threshold) {
        return new ThresholdEvaluatorStateAbsoluteChange(threshold);
    }

    /** {@inheritDoc} */
    public boolean supportsType(String type) {
        return TYPE.equals(type);
    }
    
    public static class ThresholdEvaluatorStateAbsoluteChange extends AbstractThresholdEvaluatorState {
        private BaseThresholdDefConfigWrapper m_thresholdConfig;
        private double m_change;

        private double m_lastSample = Double.NaN;
        
        private double m_previousTriggeringSample;

        public ThresholdEvaluatorStateAbsoluteChange(BaseThresholdDefConfigWrapper threshold) {
            Assert.notNull(threshold, "threshold argument cannot be null");

            setThresholdConfig(threshold);
        }

        public void setThresholdConfig(BaseThresholdDefConfigWrapper thresholdConfig) {
            Assert.notNull(thresholdConfig.getType(), "threshold must have a 'type' value set");
            Assert.notNull(thresholdConfig.getDatasourceExpression(), "threshold must have a 'ds-name' value set");
            Assert.notNull(thresholdConfig.getDsType(), "threshold must have a 'ds-type' value set");
            Assert.isTrue(thresholdConfig.hasValue(), "threshold must have a 'value' value set");
            Assert.isTrue(thresholdConfig.hasRearm(), "threshold must have a 'rearm' value set");
            Assert.isTrue(thresholdConfig.hasTrigger(), "threshold must have a 'trigger' value set");

            Assert.isTrue(TYPE.equals(thresholdConfig.getType()), "threshold for ds-name '" + thresholdConfig.getDatasourceExpression() + "' has type of '" + thresholdConfig.getType() + "', but this evaluator only supports thresholds with a 'type' value of '" + TYPE + "'");

            Assert.isTrue(!Double.isNaN(thresholdConfig.getValue()), "threshold must have a 'value' value that is a number");
            Assert.isTrue(thresholdConfig.getValue() != Double.POSITIVE_INFINITY && thresholdConfig.getValue() != Double.NEGATIVE_INFINITY, "threshold must have a 'value' value that is not positive or negative infinity");
            Assert.isTrue(thresholdConfig.getValue() != 0.0, "threshold must not be 0 for absolute change");

            m_thresholdConfig = thresholdConfig;
            setChange(thresholdConfig.getValue());
        }

        public BaseThresholdDefConfigWrapper getThresholdConfig() {
            return m_thresholdConfig;
        }

        public Status evaluate(double dsValue) {
            if(!Double.isNaN(getLastSample())) {
                double threshold = getLastSample()+getChange();

                if (getChange() < 0.0) {
                    //Negative change; care if the value is *below* the threshold
                    if (dsValue <= threshold) {
                        setPreviousTriggeringSample(getLastSample());
                        setLastSample(dsValue);
                        log().debug("evaluate: absolute negative change threshold triggered");
                        return Status.TRIGGERED;
                    }
                } else {
                    //Positive change; care if the current value is *above* the threshold
                    if (dsValue >= threshold) {
                        setPreviousTriggeringSample(getLastSample());
                        setLastSample(dsValue);
                        log().debug("evaluate: absolute positive change threshold triggered");
                        return Status.TRIGGERED;
                    }
                }
            }
            setLastSample(dsValue);
            return Status.NO_CHANGE;
        }

        public Double getLastSample() {
            return m_lastSample;
        }

        public void setLastSample(double lastSample) {
            m_lastSample = lastSample;
        }

        public Event getEventForState(Status status, Date date, double dsValue, CollectionResourceWrapper resource) {
            if (status == Status.TRIGGERED) {
                String uei=getThresholdConfig().getTriggeredUEI();
                if(uei==null || "".equals(uei)) {
                    uei=EventConstants.ABSOLUTE_CHANGE_THRESHOLD_EVENT_UEI;
                }
                return createBasicEvent(uei, date, dsValue, resource);
            } else {
                return null;
            }
        }
        
        private Event createBasicEvent(String uei, Date date, double dsValue, CollectionResourceWrapper resource) {
            Map<String,String> params = new HashMap<String,String>();
            params.put("previousValue", formatValue(getPreviousTriggeringSample()));
            params.put("changeThreshold", Double.toString(getThresholdConfig().getValue()));
            params.put("trigger", Integer.toString(getThresholdConfig().getTrigger()));
            return createBasicEvent(uei, date, dsValue, resource, params);
        }

        public double getPreviousTriggeringSample() {
            return m_previousTriggeringSample;
        }
        
        public void setPreviousTriggeringSample(double previousTriggeringSample) {
            m_previousTriggeringSample = previousTriggeringSample;
        }

        public double getChange() {
            return m_change;
        }

        public void setChange(double change) {
            m_change = change;
        }

        public ThresholdEvaluatorState getCleanClone() {
            return new ThresholdEvaluatorStateAbsoluteChange(m_thresholdConfig);
        }

        // FIXME This must be implemented correctly
        public boolean isTriggered() {
            return false;
        }

        // FIXME This must be implemented correctly
        public void clearState() {
        }
    }

}