/*
* Copyright 2007 JBoss Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Created on Dec 6, 2007
*/
package org.drools.base.evaluators;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import org.drools.RuntimeDroolsException;
import org.drools.base.BaseEvaluator;
import org.drools.base.ValueType;
import org.drools.common.EventFactHandle;
import org.drools.common.InternalFactHandle;
import org.drools.common.InternalWorkingMemory;
import org.drools.rule.VariableRestriction.ObjectVariableContextEntry;
import org.drools.rule.VariableRestriction.VariableContextEntry;
import org.drools.spi.Evaluator;
import org.drools.spi.FieldValue;
import org.drools.spi.InternalReadAccessor;
import org.drools.time.Interval;
/**
* <p>The implementation of the 'coincides' evaluator definition.</p>
*
* <p>The <b><code>coincides</code></b> evaluator correlates two events and matches when both
* happen at the same time. Optionally, the evaluator accept thresholds for the distance between
* events' start and finish timestamps.</p>
*
* <p>Lets look at an example:</p>
*
* <pre>$eventA : EventA( this coincides $eventB )</pre>
*
* <p>The previous pattern will match if and only if the start timestamps of both $eventA
* and $eventB are the same AND the end timestamp of both $eventA and $eventB also are
* the same.</p>
*
* <p>Optionally, this operator accepts one or two parameters. These parameters are the thresholds
* for the distance between matching timestamps. If only one paratemer is given, it is used for
* both start and end timestamps. If two parameters are given, then the first is used as a threshold
* for the start timestamp and the second one is used as a threshold for the end timestamp. In other
* words:</p>
*
* <pre> $eventA : EventA( this coincides[15s, 10s] $eventB ) </pre>
*
* Above pattern will match if and only if:
*
* <pre>
* abs( $eventA.startTimestamp - $eventB.startTimestamp ) <= 15s &&
* abs( $eventA.endTimestamp - $eventB.endTimestamp ) <= 10s
* </pre>
*
* <p><b>NOTE:</b> it makes no sense to use negative interval values for the parameters and the
* engine will raise an error if that happens.</p>
*
* @author etirelli
* @author mgroch
*/
public class CoincidesEvaluatorDefinition
implements
EvaluatorDefinition {
public static final Operator COINCIDES = Operator.addOperatorToRegistry( "coincides",
false );
public static final Operator COINCIDES_NOT = Operator.addOperatorToRegistry( "coincides",
true );
private static final String[] SUPPORTED_IDS = {COINCIDES.getOperatorString()};
private Map<String, CoincidesEvaluator> cache = Collections.emptyMap();
private volatile TimeIntervalParser parser = new TimeIntervalParser();
@SuppressWarnings("unchecked")
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
cache = (Map<String, CoincidesEvaluator>) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
out.writeObject( cache );
}
/**
* @inheridDoc
*/
public Evaluator getEvaluator(ValueType type,
Operator operator) {
return this.getEvaluator( type,
operator.getOperatorString(),
operator.isNegated(),
null );
}
/**
* @inheridDoc
*/
public Evaluator getEvaluator(ValueType type,
Operator operator,
String parameterText) {
return this.getEvaluator( type,
operator.getOperatorString(),
operator.isNegated(),
parameterText );
}
/**
* @inheritDoc
*/
public Evaluator getEvaluator(final ValueType type,
final String operatorId,
final boolean isNegated,
final String parameterText) {
if ( this.cache == Collections.EMPTY_MAP ) {
this.cache = new HashMap<String, CoincidesEvaluator>();
}
String key = isNegated + ":" + parameterText;
CoincidesEvaluator eval = this.cache.get( key );
if ( eval == null ) {
Long[] params = parser.parse( parameterText );
eval = new CoincidesEvaluator( type,
isNegated,
params,
parameterText );
this.cache.put( key,
eval );
}
return eval;
}
/**
* @inheritDoc
*/
public String[] getEvaluatorIds() {
return SUPPORTED_IDS;
}
/**
* @inheritDoc
*/
public boolean isNegatable() {
return true;
}
/**
* @inheritDoc
*/
public boolean operatesOnFactHandles() {
return true;
}
/**
* @inheritDoc
*/
public boolean supportsType(ValueType type) {
// supports all types, since it operates over fact handles
// Note: should we change this interface to allow checking of event classes only?
return true;
}
/**
* Implements the 'coincides' evaluator itself
*/
public static class CoincidesEvaluator extends BaseEvaluator {
private static final long serialVersionUID = 6031520837249122183L;
private long startDev;
private long endDev;
private String paramText;
public CoincidesEvaluator() {
}
public CoincidesEvaluator(final ValueType type,
final boolean isNegated,
final Long[] parameters,
final String paramText) {
super( type,
isNegated ? COINCIDES_NOT : COINCIDES );
this.paramText = paramText;
this.setParameters( parameters );
}
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
super.readExternal( in );
startDev = in.readLong();
endDev = in.readLong();
paramText = (String) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
super.writeExternal( out );
out.writeLong( startDev );
out.writeLong( endDev );
out.writeObject( paramText );
}
@Override
public Object prepareObject(InternalFactHandle handle) {
return handle;
}
@Override
public boolean isTemporal() {
return true;
}
@Override
public Interval getInterval() {
if ( this.getOperator().isNegated() ) {
return new Interval( Interval.MIN,
Interval.MAX );
}
return new Interval( 0,
0 );
}
public boolean evaluate(InternalWorkingMemory workingMemory,
final InternalReadAccessor extractor,
final Object object1,
final FieldValue object2) {
throw new RuntimeDroolsException( "The 'coincides' operator can only be used to compare one event to another, and never to compare to literal constraints." );
}
public boolean evaluateCachedRight(InternalWorkingMemory workingMemory,
final VariableContextEntry context,
final Object left) {
if ( context.rightNull ) {
return false;
}
long distStart = Math.abs( ((EventFactHandle) ((ObjectVariableContextEntry) context).right).getStartTimestamp() - ((EventFactHandle) left).getStartTimestamp() );
long distEnd = Math.abs( ((EventFactHandle) ((ObjectVariableContextEntry) context).right).getEndTimestamp() - ((EventFactHandle) left).getEndTimestamp() );
return this.getOperator().isNegated() ^ (distStart <= this.startDev && distEnd <= this.endDev);
}
public boolean evaluateCachedLeft(InternalWorkingMemory workingMemory,
final VariableContextEntry context,
final Object right) {
if ( context.extractor.isNullValue( workingMemory,
right ) ) {
return false;
}
long distStart = Math.abs( ((EventFactHandle) right).getStartTimestamp() - ((EventFactHandle) ((ObjectVariableContextEntry) context).left).getStartTimestamp() );
long distEnd = Math.abs( ((EventFactHandle) right).getEndTimestamp() - ((EventFactHandle) ((ObjectVariableContextEntry) context).left).getEndTimestamp() );
return this.getOperator().isNegated() ^ (distStart <= this.startDev && distEnd <= this.endDev);
}
public boolean evaluate(InternalWorkingMemory workingMemory,
final InternalReadAccessor extractor1,
final Object object1,
final InternalReadAccessor extractor2,
final Object object2) {
if ( extractor1.isNullValue( workingMemory,
object1 ) ) {
return false;
}
long distStart = Math.abs( ((EventFactHandle) object1).getStartTimestamp() - ((EventFactHandle) object2).getStartTimestamp() );
long distEnd = Math.abs( ((EventFactHandle) object1).getEndTimestamp() - ((EventFactHandle) object2).getEndTimestamp() );
return this.getOperator().isNegated() ^ (distStart <= this.startDev && distEnd <= this.endDev);
}
public String toString() {
return "coincides[" + startDev + ", " + endDev + "]";
}
/* (non-Javadoc)
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode() {
final int PRIME = 31;
int result = super.hashCode();
result = PRIME * result + (int) (endDev ^ (endDev >>> 32));
result = PRIME * result + (int) (startDev ^ (startDev >>> 32));
return result;
}
/* (non-Javadoc)
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals(Object obj) {
if ( this == obj ) return true;
if ( !super.equals( obj ) ) return false;
if ( getClass() != obj.getClass() ) return false;
final CoincidesEvaluator other = (CoincidesEvaluator) obj;
return endDev == other.endDev && startDev == other.startDev;
}
/**
* This methods sets the parameters appropriately.
*
* @param parameters
*/
private void setParameters(Long[] parameters) {
if ( parameters == null || parameters.length == 0 ) {
// open bounded range
this.startDev = 0;
this.endDev = 0;
return;
} else {
for( Long param : parameters ) {
if( param.longValue() < 0 ) {
throw new RuntimeDroolsException( "[Coincides Evaluator]: negative values not allowed for temporal distance thresholds: '" + paramText + "'" );
}
}
if ( parameters.length == 1 ) {
// same deviation for both
this.startDev = parameters[0].longValue();
this.endDev = parameters[0].longValue();
} else if ( parameters.length == 2 ) {
// different deviation
this.startDev = parameters[0].longValue();
this.endDev = parameters[1].longValue();
} else {
throw new RuntimeDroolsException( "[Coincides Evaluator]: Not possible to have more than 2 parameters: '" + paramText + "'" );
}
}
}
}
}