/*
* 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 <code>finishedby</code> evaluator definition.</p>
*
* <p>The <b><code>finishedby</code></b> evaluator correlates two events and matches when the current event
* start timestamp happens before the correlated event start timestamp, but both end timestamps occur at
* the same time. This is the symmetrical opposite of <code>finishes</code> evaluator.</p>
*
* <p>Lets look at an example:</p>
*
* <pre>$eventA : EventA( this finishedby $eventB )</pre>
*
* <p>The previous pattern will match if and only if the $eventA starts before $eventB starts and finishes
* at the same time $eventB finishes. In other words:</p>
*
* <pre>
* $eventA.startTimestamp < $eventB.startTimestamp &&
* $eventA.endTimestamp == $eventB.endTimestamp
* </pre>
*
* <p>The <b><code>finishedby</code></b> evaluator accepts one optional parameter. If it is defined, it determines
* the maximum distance between the end timestamp of both events in order for the operator to match. Example:</p>
*
* <pre>$eventA : EventA( this finishedby[ 5s ] $eventB )</pre>
*
* Will match if and only if:
*
* <pre>
* $eventA.startTimestamp < $eventB.startTimestamp &&
* abs( $eventA.endTimestamp - $eventB.endTimestamp ) <= 5s
* </pre>
*
* <p><b>NOTE:</b> it makes no sense to use a negative interval value for the parameter and the
* engine will raise an exception if that happens.</p>
*
* @author etirelli
* @author mgroch
*/
public class FinishedByEvaluatorDefinition
implements
EvaluatorDefinition {
public static final Operator FINISHED_BY = Operator.addOperatorToRegistry( "finishedby",
false );
public static final Operator NOT_FINISHED_BY = Operator.addOperatorToRegistry( "finishedby",
true );
private static final String[] SUPPORTED_IDS = {FINISHED_BY.getOperatorString()};
private Map<String, FinishedByEvaluator> cache = Collections.emptyMap();
private volatile TimeIntervalParser parser = new TimeIntervalParser();
@SuppressWarnings("unchecked")
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
cache = (Map<String, FinishedByEvaluator>) 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) {
return this.getEvaluator( type,
operatorId,
isNegated,
parameterText,
Target.HANDLE,
Target.HANDLE );
}
/**
* @inheritDoc
*/
public Evaluator getEvaluator(final ValueType type,
final String operatorId,
final boolean isNegated,
final String parameterText,
final Target left,
final Target right ) {
if ( this.cache == Collections.EMPTY_MAP ) {
this.cache = new HashMap<String, FinishedByEvaluator>();
}
String key = isNegated + ":" + parameterText;
FinishedByEvaluator eval = this.cache.get( key );
if ( eval == null ) {
Long[] params = parser.parse( parameterText );
eval = new FinishedByEvaluator( 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 Target getTarget() {
return Target.HANDLE;
}
/**
* @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 'finishedby' evaluator itself
*/
public static class FinishedByEvaluator extends BaseEvaluator {
private static final long serialVersionUID = -5156972073099070733L;
private long endDev;
private String paramText;
public FinishedByEvaluator() {
}
public FinishedByEvaluator(final ValueType type,
final boolean isNegated,
final Long[] parameters,
final String paramText) {
super( type,
isNegated ? NOT_FINISHED_BY : FINISHED_BY );
this.paramText = paramText;
this.setParameters( parameters );
}
public void readExternal(ObjectInput in) throws IOException,
ClassNotFoundException {
super.readExternal( in );
endDev = in.readLong();
paramText = (String) in.readObject();
}
public void writeExternal(ObjectOutput out) throws IOException {
super.writeExternal( out );
out.writeLong( endDev );
out.writeObject( paramText );
}
@Override
public Object prepareLeftObject(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( Interval.MIN,
0 );
}
public boolean evaluate(InternalWorkingMemory workingMemory,
final InternalReadAccessor extractor,
final Object object1,
final FieldValue object2) {
throw new RuntimeDroolsException( "The 'finishedby' 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 = ((EventFactHandle) left).getStartTimestamp() - ((EventFactHandle) ((ObjectVariableContextEntry) context).right).getStartTimestamp();
long distEnd = Math.abs( ((EventFactHandle) left).getEndTimestamp() - ((EventFactHandle) ((ObjectVariableContextEntry) context).right).getEndTimestamp() );
return this.getOperator().isNegated() ^ (distStart > 0 && distEnd <= this.endDev);
}
public boolean evaluateCachedLeft(InternalWorkingMemory workingMemory,
final VariableContextEntry context,
final Object right) {
if ( context.extractor.isNullValue( workingMemory,
right ) ) {
return false;
}
long distStart = ((EventFactHandle) ((ObjectVariableContextEntry) context).left).getStartTimestamp() - ((EventFactHandle) right).getStartTimestamp();
long distEnd = Math.abs( ((EventFactHandle) ((ObjectVariableContextEntry) context).left).getEndTimestamp() - ((EventFactHandle) right).getEndTimestamp() );
return this.getOperator().isNegated() ^ (distStart > 0 && 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 = ((EventFactHandle) object2).getStartTimestamp() - ((EventFactHandle) object1).getStartTimestamp();
long distEnd = Math.abs( ((EventFactHandle) object2).getEndTimestamp() - ((EventFactHandle) object1).getEndTimestamp() );
return this.getOperator().isNegated() ^ (distStart > 0 && distEnd <= this.endDev);
}
public String toString() {
return "finishedby[" + ((paramText != null) ? paramText : "") + "]";
}
/* (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));
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 FinishedByEvaluator other = (FinishedByEvaluator) obj;
return endDev == other.endDev;
}
/**
* This methods sets the parameters appropriately.
*
* @param parameters
*/
private void setParameters(Long[] parameters) {
if ( parameters == null || parameters.length == 0 ) {
this.endDev = 0;
} else if ( parameters.length == 1 ) {
if( parameters[0].longValue() >= 0 ) {
// defined deviation for end timestamp
this.endDev = parameters[0].longValue();
} else {
throw new RuntimeDroolsException("[FinishedBy Evaluator]: Not possible to use negative parameter: '" + paramText + "'");
}
} else {
throw new RuntimeDroolsException( "[FinishedBy Evaluator]: Not possible to use " + parameters.length + " parameters: '" + paramText + "'" );
}
}
}
}
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