/************************************************************************************** * 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.StatementContext; import com.espertech.esper.epl.expression.ExprNode; import com.espertech.esper.util.JavaClassHelper; import com.espertech.esper.view.*; import java.util.List; /** * Factory for {@link TimeWindowView}. */ public class TimeWindowViewFactory implements DataWindowViewFactory, DataWindowViewWithPrevious { /** * Number of msec before expiry. */ protected long millisecondsBeforeExpiry; private EventType eventType; public void setViewParameters(ViewFactoryContext viewFactoryContext, List<ExprNode> expressionParameters) throws ViewParameterException { List<Object> viewParameters = ViewFactorySupport.validateAndEvaluate("Time window view", viewFactoryContext.getStatementContext(), expressionParameters); String errorMessage = "Time window view requires a single numeric or time period parameter"; if (viewParameters.size() != 1) { throw new ViewParameterException(errorMessage); } Object parameter = viewParameters.get(0); 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(); } } if (millisecondsBeforeExpiry < 1) { throw new ViewParameterException("Time window view requires a size of at least 1 msec"); } } public void attach(EventType parentEventType, StatementContext statementContext, ViewFactory optionalParentFactory, List<ViewFactory> parentViewFactories) throws ViewParameterException { this.eventType = parentEventType; } public Object makePreviousGetter() { return new RandomAccessByIndexGetter(); } public View makeView(AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext) { IStreamRandomAccess randomAccess = ViewServiceHelper.getOptPreviousExprRandomAccess(agentInstanceViewFactoryContext); return new TimeWindowView(agentInstanceViewFactoryContext, this, millisecondsBeforeExpiry, randomAccess); } public EventType getEventType() { return eventType; } public boolean canReuse(View view) { if (!(view instanceof TimeWindowView)) { return false; } TimeWindowView myView = (TimeWindowView) view; if (myView.getMillisecondsBeforeExpiry() != millisecondsBeforeExpiry) { return false; } // For reuse of the time window it doesn't matter if it provides random access or not return myView.isEmpty(); } }