/**************************************************************************************
* 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.epl.expression;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.client.EventType;
import com.espertech.esper.metrics.instrumentation.InstrumentationHelper;
/**
* Represents an stream selector that returns the streams underlying event, or null if undefined.
*/
public class ExprStreamUnderlyingNodeImpl extends ExprNodeBase implements ExprEvaluator, ExprStreamUnderlyingNode
{
private final String streamName;
private final boolean isWildcard;
private int streamNum = -1;
private Class type;
private static final long serialVersionUID = 6611578192872250478L;
/**
* Ctor.
* @param streamName is the name of the stream for which to return the underlying event
*/
public ExprStreamUnderlyingNodeImpl(String streamName, boolean isWildcard)
{
if ((streamName == null) && (!isWildcard))
{
throw new IllegalArgumentException("Stream name is null");
}
this.streamName = streamName;
this.isWildcard = isWildcard;
}
public ExprStreamUnderlyingNodeImpl(String streamName, boolean wildcard, int streamNum, Class type) {
this.streamName = streamName;
isWildcard = wildcard;
this.streamNum = streamNum;
this.type = type;
}
@Override
public ExprEvaluator getExprEvaluator() {
return this;
}
/**
* Returns the stream name.
* @return stream name
*/
public String getStreamName()
{
return streamName;
}
public void validate(ExprValidationContext validationContext) throws ExprValidationException
{
if (isWildcard) {
if (validationContext.getStreamTypeService().getStreamNames().length > 1) {
throw new ExprValidationException("Wildcard must be stream wildcard if specifying multiple streams, use the 'streamname.*' syntax instead");
}
streamNum = 0;
}
else {
streamNum = validationContext.getStreamTypeService().getStreamNumForStreamName(streamName);
}
if (streamNum == -1)
{
throw new ExprValidationException("Stream by name '" + streamName + "' could not be found among all streams");
}
EventType eventType = validationContext.getStreamTypeService().getEventTypes()[streamNum];
type = eventType.getUnderlyingType();
}
public Class getType()
{
if (streamNum == -1)
{
throw new IllegalStateException("Stream underlying node has not been validated");
}
return type;
}
public boolean isConstantResult()
{
return false;
}
/**
* Returns stream id supplying the property value.
* @return stream number
*/
public int getStreamId()
{
if (streamNum == -1)
{
throw new IllegalStateException("Stream underlying node has not been validated");
}
return streamNum;
}
public String toString()
{
return "streamName=" + streamName +
" streamNum=" + streamNum;
}
public Object evaluate(EventBean[] eventsPerStream, boolean isNewData, ExprEvaluatorContext exprEvaluatorContext)
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().qExprStreamUnd(this);}
EventBean theEvent = eventsPerStream[streamNum];
if (theEvent == null)
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aExprStreamUnd(null);}
return null;
}
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aExprStreamUnd(theEvent.getUnderlying());}
return theEvent.getUnderlying();
}
public String toExpressionString()
{
StringBuilder buffer = new StringBuilder();
buffer.append(streamName);
return buffer.toString();
}
public boolean equalsNode(ExprNode node)
{
if (!(node instanceof ExprStreamUnderlyingNodeImpl))
{
return false;
}
ExprStreamUnderlyingNodeImpl other = (ExprStreamUnderlyingNodeImpl) node;
if (this.isWildcard != other.isWildcard) {
return false;
}
if (this.isWildcard) {
return true;
}
return (this.streamName.equals(other.streamName));
}
}