/**************************************************************************************
* 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.metrics.instrumentation.InstrumentationHelper;
import com.espertech.esper.util.JavaClassHelper;
import com.espertech.esper.util.LikeUtil;
import java.io.StringWriter;
/**
* Represents the like-clause in an expression tree.
*/
public class ExprLikeNode extends ExprNodeBase implements ExprEvaluator
{
private final boolean isNot;
private boolean isNumericValue;
private boolean isConstantPattern;
private transient LikeUtil likeUtil;
private transient ExprEvaluator[] evaluators;
private static final long serialVersionUID = 34888860063217132L;
/**
* Ctor.
* @param not is true if this is a "not like", or false if just a like
*/
public ExprLikeNode(boolean not)
{
this.isNot = not;
}
public ExprEvaluator getExprEvaluator()
{
return this;
}
public void validate(ExprValidationContext validationContext) throws ExprValidationException
{
if ((this.getChildNodes().length != 2) && (this.getChildNodes().length != 3))
{
throw new ExprValidationException("The 'like' operator requires 2 (no escape) or 3 (with escape) child expressions");
}
evaluators = ExprNodeUtility.getEvaluators(this.getChildNodes());
// check eval child node - can be String or numeric
Class evalChildType = evaluators[0].getType();
isNumericValue = JavaClassHelper.isNumeric(evalChildType);
if ((evalChildType != String.class) && (!isNumericValue))
{
throw new ExprValidationException("The 'like' operator requires a String or numeric type left-hand expression");
}
// check pattern child node
ExprEvaluator patternChildNode = evaluators[1];
Class patternChildType = patternChildNode.getType();
if (patternChildType != String.class)
{
throw new ExprValidationException("The 'like' operator requires a String-type pattern expression");
}
if (getChildNodes()[1].isConstantResult())
{
isConstantPattern = true;
}
// check escape character node
if (this.getChildNodes().length == 3)
{
ExprEvaluator escapeChildNode = evaluators[2];
if (escapeChildNode.getType() != String.class)
{
throw new ExprValidationException("The 'like' operator escape parameter requires a character-type value");
}
}
}
public Class getType()
{
return Boolean.class;
}
public boolean isConstantResult()
{
return false;
}
public Object evaluate(EventBean[] eventsPerStream, boolean isNewData, ExprEvaluatorContext exprEvaluatorContext)
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().qExprLike(this);}
if (likeUtil == null)
{
String patternVal = (String) evaluators[1].evaluate(eventsPerStream, isNewData, exprEvaluatorContext);
if (patternVal == null)
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aExprLike(null);}
return null;
}
String escape = "\\";
Character escapeCharacter = null;
if (this.getChildNodes().length == 3)
{
escape = (String) evaluators[2].evaluate(eventsPerStream, isNewData,exprEvaluatorContext);
}
if (escape.length() > 0)
{
escapeCharacter = escape.charAt(0);
}
likeUtil = new LikeUtil(patternVal, escapeCharacter, false);
}
else
{
if (!isConstantPattern)
{
String patternVal = (String) evaluators[1].evaluate(eventsPerStream, isNewData,exprEvaluatorContext);
if (patternVal == null)
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aExprLike(null);}
return null;
}
likeUtil.resetPattern(patternVal);
}
}
Object evalValue = evaluators[0].evaluate(eventsPerStream, isNewData,exprEvaluatorContext);
if (evalValue == null)
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aExprLike(null);}
return null;
}
if (isNumericValue)
{
evalValue = evalValue.toString();
}
Boolean result = likeUtil.compare( (String) evalValue);
if (isNot)
{
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aExprLike(!result);}
return !result;
}
if (InstrumentationHelper.ENABLED) { InstrumentationHelper.get().aExprLike(result);}
return result;
}
public boolean equalsNode(ExprNode node_)
{
if (!(node_ instanceof ExprLikeNode))
{
return false;
}
ExprLikeNode other = (ExprLikeNode) node_;
if (this.isNot != other.isNot)
{
return false;
}
return true;
}
public void toPrecedenceFreeEPL(StringWriter writer) {
this.getChildNodes()[0].toEPL(writer, getPrecedence());
if (isNot) {
writer.append(" not");
}
writer.append(" like ");
this.getChildNodes()[1].toEPL(writer, getPrecedence());
if (this.getChildNodes().length == 3)
{
writer.append(" escape ");
this.getChildNodes()[2].toEPL(writer, getPrecedence());
}
}
public ExprPrecedenceEnum getPrecedence() {
return ExprPrecedenceEnum.RELATIONAL_BETWEEN_IN;
}
/**
* Returns true if this is a "not like", or false if just a like
* @return indicator whether negated or not
*/
public boolean isNot()
{
return isNot;
}
}