/**************************************************************************************
* 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.ext;
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.ExprNode;
import com.espertech.esper.epl.expression.ExprNodeUtility;
import com.espertech.esper.util.JavaClassHelper;
import com.espertech.esper.view.*;
import com.espertech.esper.view.window.RandomAccessByIndexGetter;
import java.util.List;
/**
* Factory for views for time-ordering events.
*/
public class TimeOrderViewFactory implements DataWindowViewFactory, DataWindowViewWithPrevious
{
private List<ExprNode> viewParameters;
/**
* The timestamp expression.
*/
protected ExprNode timestampExpression;
/**
* The interval to wait for newer events to arrive.
*/
protected long intervalSize;
private EventType eventType;
public void setViewParameters(ViewFactoryContext viewFactoryContext, List<ExprNode> expressionParameters) throws ViewParameterException
{
viewParameters = expressionParameters;
}
public void attach(EventType parentEventType, StatementContext statementContext, ViewFactory optionalParentFactory, List<ViewFactory> parentViewFactories) throws ViewParameterException
{
ExprNode[] validated = ViewFactorySupport.validate(getViewName(), parentEventType, statementContext, viewParameters, true);
if (viewParameters.size() != 2)
{
throw new ViewParameterException(getViewParamMessage());
}
if (!JavaClassHelper.isNumeric(validated[0].getExprEvaluator().getType()))
{
throw new ViewParameterException(getViewParamMessage());
}
timestampExpression = validated[0];
ExprEvaluatorContextStatement exprEvaluatorContext = new ExprEvaluatorContextStatement(statementContext);
Object parameter = ViewFactorySupport.evaluateAssertNoProperties(getViewName(), validated[1], 1, exprEvaluatorContext);
if (!(parameter instanceof Number))
{
throw new ViewParameterException(getViewParamMessage());
}
else
{
Number param = (Number) parameter;
if (JavaClassHelper.isFloatingPointNumber(param))
{
intervalSize = Math.round(1000d * param.doubleValue());
}
else
{
intervalSize = 1000 * param.longValue();
}
}
if (intervalSize < 1)
{
throw new ViewParameterException(getViewName() + " view requires a size of at least 1 msec");
}
eventType = parentEventType;
}
public Object makePreviousGetter() {
return new RandomAccessByIndexGetter();
}
public View makeView(AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext)
{
IStreamSortRankRandomAccess sortedRandomAccess = ViewServiceHelper.getOptPreviousExprSortedRankedAccess(agentInstanceViewFactoryContext);
return new TimeOrderView(agentInstanceViewFactoryContext, this, timestampExpression, timestampExpression.getExprEvaluator(), intervalSize, sortedRandomAccess);
}
public EventType getEventType()
{
return eventType;
}
public boolean canReuse(View view)
{
if (!(view instanceof TimeOrderView))
{
return false;
}
TimeOrderView other = (TimeOrderView) view;
if ((other.getIntervalSize() != intervalSize) ||
(!ExprNodeUtility.deepEquals(other.getTimestampExpression(), timestampExpression)))
{
return false;
}
return other.isEmpty();
}
public String getViewName() {
return "Time-Order";
}
private String getViewParamMessage() {
return getViewName() + " view requires the expression supplying timestamp values, and a numeric or time period parameter for interval size";
}
}