/**************************************************************************************
* 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.core.start;
import com.espertech.esper.core.context.util.AgentInstanceViewFactoryChainContext;
import com.espertech.esper.epl.core.ViewResourceDelegateVerified;
import com.espertech.esper.epl.core.ViewResourceDelegateVerifiedStream;
import com.espertech.esper.epl.expression.*;
import com.espertech.esper.view.DataWindowViewWithPrevious;
import com.espertech.esper.view.ViewFactory;
import com.espertech.esper.view.window.RandomAccessByIndexGetter;
import com.espertech.esper.view.window.RelativeAccessByEventNIndexMap;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Starts and provides the stop method for EPL statements.
*/
public class EPStatementStartMethodHelperPrevious
{
public static Map<ExprPreviousNode, ExprPreviousEvalStrategy> compilePreviousNodeStrategies(ViewResourceDelegateVerified viewResourceDelegate, AgentInstanceViewFactoryChainContext[] contexts) {
if (!viewResourceDelegate.isHasPrevious()) {
return Collections.emptyMap();
}
Map<ExprPreviousNode, ExprPreviousEvalStrategy> strategies = new HashMap<ExprPreviousNode, ExprPreviousEvalStrategy>();
for (int streamNum = 0; streamNum < contexts.length; streamNum++) {
// get stream-specific info
ViewResourceDelegateVerifiedStream delegate = viewResourceDelegate.getPerStream()[streamNum];
// obtain getter
handlePrevious(delegate.getPreviousRequests(), contexts[streamNum].getPreviousNodeGetter(), strategies);
}
return strategies;
}
public static DataWindowViewWithPrevious findPreviousViewFactory(List<ViewFactory> factories) {
ViewFactory factoryFound = null;
for (ViewFactory factory : factories) {
if (factory instanceof DataWindowViewWithPrevious) {
factoryFound = factory;
break;
}
}
if (factoryFound == null) {
throw new RuntimeException("Failed to find 'previous'-handling view factory"); // was verified earlier, should not occur
}
return (DataWindowViewWithPrevious) factoryFound;
}
private static void handlePrevious(List<ExprPreviousNode> previousRequests, Object previousNodeGetter, Map<ExprPreviousNode, ExprPreviousEvalStrategy> strategies) {
if (previousRequests.isEmpty()) {
return;
}
RandomAccessByIndexGetter randomAccessGetter = null;
RelativeAccessByEventNIndexMap relativeAccessGetter = null;
if (previousNodeGetter instanceof RandomAccessByIndexGetter) {
randomAccessGetter = (RandomAccessByIndexGetter) previousNodeGetter;
}
else if (previousNodeGetter instanceof RelativeAccessByEventNIndexMap) {
relativeAccessGetter = (RelativeAccessByEventNIndexMap) previousNodeGetter;
}
else {
throw new RuntimeException("Unexpected 'previous' handler: " + previousNodeGetter);
}
for (ExprPreviousNode previousNode : previousRequests) {
int streamNumber = previousNode.getStreamNumber();
PreviousType previousType = previousNode.getPreviousType();
ExprPreviousEvalStrategy evaluator;
if (previousType == PreviousType.PREVWINDOW) {
evaluator = new ExprPreviousEvalStrategyWindow(streamNumber, previousNode.getChildNodes()[1].getExprEvaluator(), previousNode.getResultType().getComponentType(),
randomAccessGetter, relativeAccessGetter);
}
else if (previousType == PreviousType.PREVCOUNT) {
evaluator = new ExprPreviousEvalStrategyCount(streamNumber, randomAccessGetter, relativeAccessGetter);
}
else {
evaluator = new ExprPreviousEvalStrategyPrev(streamNumber, previousNode.getChildNodes()[0].getExprEvaluator(), previousNode.getChildNodes()[1].getExprEvaluator(),
randomAccessGetter, relativeAccessGetter, previousNode.isConstantIndex(), previousNode.getConstantIndexNumber(), previousType == PreviousType.PREVTAIL);
}
strategies.put(previousNode, evaluator);
}
}
}