/**************************************************************************************
* 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.window;
import com.espertech.esper.client.EventType;
import com.espertech.esper.core.context.util.AgentInstanceViewFactoryChainContext;
import com.espertech.esper.core.service.ExprEvaluatorContextStatement;
import com.espertech.esper.core.service.StatementContext;
import com.espertech.esper.epl.expression.ExprEvaluator;
import com.espertech.esper.epl.expression.ExprNode;
import com.espertech.esper.epl.expression.ExprNodeUtility;
import com.espertech.esper.util.JavaClassHelper;
import com.espertech.esper.view.*;
import java.util.List;
/**
* Factory for {@link com.espertech.esper.view.window.ExternallyTimedBatchView}.
*/
public class ExternallyTimedBatchViewFactory implements DataWindowBatchingViewFactory, DataWindowViewFactory, DataWindowViewWithPrevious
{
private List<ExprNode> viewParameters;
private EventType eventType;
/**
* The timestamp property name.
*/
protected ExprNode timestampExpression;
protected ExprEvaluator timestampExpressionEval;
protected Long optionalReferencePoint;
/**
* The number of msec to expire.
*/
protected long millisecondsBeforeExpiry;
public void setViewParameters(ViewFactoryContext viewFactoryContext, List<ExprNode> expressionParameters) throws ViewParameterException
{
this.viewParameters = expressionParameters;
}
public void attach(EventType parentEventType, StatementContext statementContext, ViewFactory optionalParentFactory, List<ViewFactory> parentViewFactories) throws ViewParameterException
{
final String windowName = "Externally-timed batch window";
ExprNode[] validated = ViewFactorySupport.validate(windowName, parentEventType, statementContext, viewParameters, true);
String errorMessage = "Externally-timed batch window view requires a timestamp expression and a numeric or time period parameter for window size and an optional long-typed reference point in msec, and an optional list of control keywords as a string parameter (please see the documentation)";
if (viewParameters.size() < 2 || viewParameters.size() > 3) {
throw new ViewParameterException(errorMessage);
}
// validate first parameter: timestamp expression
if (!JavaClassHelper.isNumeric(validated[0].getExprEvaluator().getType()))
{
throw new ViewParameterException(errorMessage);
}
timestampExpression = validated[0];
timestampExpressionEval = timestampExpression.getExprEvaluator();
// validate second: window size
ViewFactorySupport.assertReturnsNonConstant(windowName, validated[0], 0);
Object parameter = ViewFactorySupport.evaluateAssertNoProperties(windowName, validated[1], 1, new ExprEvaluatorContextStatement(statementContext));
if (!(parameter instanceof Number))
{
throw new ViewParameterException(errorMessage);
}
else
{
Number param = (Number) parameter;
if (JavaClassHelper.isFloatingPointNumber(param))
{
millisecondsBeforeExpiry = Math.round(1000d * param.doubleValue());
}
else
{
millisecondsBeforeExpiry = 1000 * param.longValue();
}
}
// validate optional parameters
if (validated.length == 3) {
Object constant = ViewFactorySupport.validateAndEvaluate(windowName, statementContext, validated[2]);
if ((!(constant instanceof Number)) || (JavaClassHelper.isFloatingPointNumber((Number)constant)))
{
throw new ViewParameterException("Externally-timed batch view requires a Long-typed reference point in msec as a third parameter");
}
optionalReferencePoint = ((Number) constant).longValue();
}
this.eventType = parentEventType;
}
public Object makePreviousGetter() {
return new RelativeAccessByEventNIndexMap();
}
public View makeView(AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext)
{
IStreamRelativeAccess relativeAccessByEvent = ViewServiceHelper.getOptPreviousExprRelativeAccess(agentInstanceViewFactoryContext);
return new ExternallyTimedBatchView(this, timestampExpression, timestampExpressionEval, millisecondsBeforeExpiry, optionalReferencePoint, relativeAccessByEvent, agentInstanceViewFactoryContext);
}
public EventType getEventType()
{
return eventType;
}
public boolean canReuse(View view)
{
if (!(view instanceof ExternallyTimedBatchView))
{
return false;
}
ExternallyTimedBatchView myView = (ExternallyTimedBatchView) view;
if ((myView.getMillisecondsBeforeExpiry() != millisecondsBeforeExpiry) ||
(!ExprNodeUtility.deepEquals(myView.getTimestampExpression(), timestampExpression)))
{
return false;
}
return myView.isEmpty();
}
}