/**************************************************************************************
* Copyright (C) 2008 EsperTech, Inc. All rights reserved. *
* http://esper.codehaus.org *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
**************************************************************************************/
package com.espertech.esper.view.std;
import com.espertech.esper.client.EventType;
import com.espertech.esper.client.annotation.Hint;
import com.espertech.esper.client.annotation.HintEnum;
import com.espertech.esper.core.context.util.AgentInstanceViewFactoryChainContext;
import com.espertech.esper.core.service.StatementContext;
import com.espertech.esper.epl.expression.ExprNode;
import com.espertech.esper.epl.expression.ExprNodeUtility;
import com.espertech.esper.view.*;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import java.util.List;
import java.util.Set;
/**
* Factory for {@link GroupByView} instances.
*/
public class GroupByViewFactory implements ViewFactory, GroupByViewFactoryMarker
{
private static Log log = LogFactory.getLog(GroupByViewFactory.class);
/**
* View parameters.
*/
protected List<ExprNode> viewParameters;
/**
* List of criteria expressions.
*/
protected ExprNode[] criteriaExpressions;
private EventType eventType;
protected boolean isReclaimAged;
protected double reclaimMaxAge;
protected double reclaimFrequency;
public void setViewParameters(ViewFactoryContext viewFactoryContext, List<ExprNode> expressionParameters) throws ViewParameterException
{
this.viewParameters = expressionParameters;
Hint reclaimGroupAged = HintEnum.RECLAIM_GROUP_AGED.getHint(viewFactoryContext.getStatementContext().getAnnotations());
if (reclaimGroupAged != null) {
isReclaimAged = true;
String hintValueMaxAge = HintEnum.RECLAIM_GROUP_AGED.getHintAssignedValue(reclaimGroupAged);
if (hintValueMaxAge == null)
{
throw new ViewParameterException("Required hint value for hint '" + HintEnum.RECLAIM_GROUP_AGED + "' has not been provided");
}
try {
reclaimMaxAge = Double.parseDouble(hintValueMaxAge);
}
catch (RuntimeException ex) {
throw new ViewParameterException("Required hint value for hint '" + HintEnum.RECLAIM_GROUP_AGED + "' value '" + hintValueMaxAge + "' could not be parsed as a double value");
}
String hintValueFrequency = HintEnum.RECLAIM_GROUP_FREQ.getHintAssignedValue(reclaimGroupAged);
if (hintValueFrequency == null)
{
reclaimFrequency = reclaimMaxAge;
}
else {
try {
reclaimFrequency = Double.parseDouble(hintValueFrequency);
}
catch (RuntimeException ex) {
throw new ViewParameterException("Required hint value for hint '" + HintEnum.RECLAIM_GROUP_FREQ + "' value '" + hintValueFrequency + "' could not be parsed as a double value");
}
}
if (reclaimMaxAge < 0.100) {
log.warn("Reclaim max age parameter is less then 100 milliseconds, are your sure?");
}
if (log.isDebugEnabled()) {
log.debug("Using reclaim-aged strategy for group-window age " + reclaimMaxAge + " frequency " + reclaimFrequency);
}
}
}
public void attach(EventType parentEventType, StatementContext statementContext, ViewFactory optionalParentFactory, List<ViewFactory> parentViewFactories) throws ViewParameterException
{
criteriaExpressions = ViewFactorySupport.validate("Group-by view", parentEventType, statementContext, viewParameters, false);
if (criteriaExpressions.length == 0)
{
String errorMessage = "Unique-by view requires a one or more expressions provinding unique values as parameters";
throw new ViewParameterException(errorMessage);
}
this.eventType = parentEventType;
}
/**
* Returns the names of fields to group by
* @return field names
*/
public ExprNode[] getCriteriaExpressions()
{
return criteriaExpressions;
}
public View makeView(AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext)
{
if (isReclaimAged) {
return new GroupByViewReclaimAged(agentInstanceViewFactoryContext, criteriaExpressions, ExprNodeUtility.getEvaluators(criteriaExpressions), reclaimMaxAge, reclaimFrequency);
}
return new GroupByViewImpl(agentInstanceViewFactoryContext, criteriaExpressions, ExprNodeUtility.getEvaluators(criteriaExpressions));
}
public EventType getEventType()
{
return eventType;
}
public boolean canReuse(View view)
{
if (!(view instanceof GroupByView))
{
return false;
}
if (isReclaimAged) {
return false;
}
GroupByView myView = (GroupByView) view;
if (!ExprNodeUtility.deepEquals(myView.getCriteriaExpressions(), criteriaExpressions))
{
return false;
}
return true;
}
public boolean isRetainAged() {
return isReclaimAged;
}
}