com.espertech.esper.view.window.TimeWindowViewFactory Maven / Gradle / Ivy

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Complex event processing and event series analysis component
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/**************************************************************************************
 * Copyright (C) 2006-2015 EsperTech Inc. All rights reserved.                        *
 * http://www.espertech.com/esper                                                          *
 * 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.collection.ViewUpdatedCollection;
import com.espertech.esper.core.context.util.AgentInstanceViewFactoryChainContext;
import com.espertech.esper.core.service.StatementContext;
import com.espertech.esper.epl.expression.core.ExprNode;
import com.espertech.esper.epl.expression.time.ExprTimePeriodEvalDeltaConst;
import com.espertech.esper.view.*;

import java.util.List;

/**
 * Factory for {@link TimeWindowView}.
 */
public class TimeWindowViewFactory implements DataWindowViewFactory, DataWindowViewWithPrevious
{
    protected ExprTimePeriodEvalDeltaConst timeDeltaComputation;

    private EventType eventType;

    public void setViewParameters(ViewFactoryContext viewFactoryContext, List expressionParameters) throws ViewParameterException
    {
        if (expressionParameters.size() != 1) {
            throw new ViewParameterException(getViewParamMessage());
        }
        timeDeltaComputation = ViewFactoryTimePeriodHelper.validateAndEvaluateTimeDelta(getViewName(), viewFactoryContext.getStatementContext(), expressionParameters.get(0), getViewParamMessage(), 0);
    }

    public void attach(EventType parentEventType, StatementContext statementContext, ViewFactory optionalParentFactory, List parentViewFactories) throws ViewParameterException
    {
        this.eventType = parentEventType;
    }

    public Object makePreviousGetter() {
        return new RandomAccessByIndexGetter();
    }

    public View makeView(AgentInstanceViewFactoryChainContext agentInstanceViewFactoryContext)
    {
        ViewUpdatedCollection randomAccess = agentInstanceViewFactoryContext.getStatementContext().getViewServicePreviousFactory().getOptPreviousExprRandomAccess(agentInstanceViewFactoryContext);
        return new TimeWindowView(agentInstanceViewFactoryContext, this, timeDeltaComputation, randomAccess);
    }

    public EventType getEventType()
    {
        return eventType;
    }

    public boolean canReuse(View view)
    {
        if (!(view instanceof TimeWindowView))
        {
            return false;
        }

        TimeWindowView myView = (TimeWindowView) view;
        if (!timeDeltaComputation.equalsTimePeriod(myView.getTimeDeltaComputation()))
        {
            return false;
        }

        // For reuse of the time window it doesn't matter if it provides random access or not
        return myView.isEmpty();
    }

    public String getViewName() {
        return "Time";
    }

    public ExprTimePeriodEvalDeltaConst getTimeDeltaComputation() {
        return timeDeltaComputation;
    }

    private String getViewParamMessage() {
        return getViewName() + " view requires a single numeric or time period parameter";
    }
}