/*
***************************************************************************************
* Copyright (C) 2006 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.client.soda;
import java.io.StringWriter;
/**
* Minimum-value per-row expression (not aggregating) determines the minimum value among a set of values.
*/
public class MinRowExpression extends ExpressionBase {
private static final long serialVersionUID = 8073671607714248651L;
/**
* Ctor - for use to create an expression tree, without child expression.
* <p>
* Use add methods to add child expressions to acts upon.
*/
public MinRowExpression() {
}
/**
* Ctor.
*
* @param propertyOne the name of the property providing a value to determine the minimum of
* @param propertyTwo the name of the property providing a value to determine the minimum of
* @param moreProperties optional additional properties to consider
*/
public MinRowExpression(String propertyOne, String propertyTwo, String[] moreProperties) {
addChild(new PropertyValueExpression(propertyOne));
addChild(new PropertyValueExpression(propertyTwo));
for (int i = 0; i < moreProperties.length; i++) {
addChild(new PropertyValueExpression(moreProperties[i]));
}
}
/**
* Ctor.
*
* @param exprOne provides a value to determine the maximum of
* @param exprTwo provides a value to determine the maximum of
* @param moreExpressions optional additional values to consider
*/
public MinRowExpression(Expression exprOne, Expression exprTwo, Expression... moreExpressions) {
addChild(exprOne);
addChild(exprTwo);
for (int i = 0; i < moreExpressions.length; i++) {
addChild(moreExpressions[i]);
}
}
/**
* Add a constant to include in the computation.
*
* @param object constant to add
* @return expression
*/
public MinRowExpression add(Object object) {
this.getChildren().add(new ConstantExpression(object));
return this;
}
/**
* Add an expression to include in the computation.
*
* @param expression to add
* @return expression
*/
public MinRowExpression add(Expression expression) {
this.getChildren().add(expression);
return this;
}
/**
* Add a property to include in the computation.
*
* @param propertyName is the name of the property
* @return expression
*/
public MinRowExpression add(String propertyName) {
this.getChildren().add(new PropertyValueExpression(propertyName));
return this;
}
public ExpressionPrecedenceEnum getPrecedence() {
return ExpressionPrecedenceEnum.UNARY;
}
public void toPrecedenceFreeEPL(StringWriter writer) {
writer.write("min(");
String delimiter = "";
for (Expression expr : this.getChildren()) {
writer.write(delimiter);
expr.toEPL(writer, ExpressionPrecedenceEnum.MINIMUM);
delimiter = ",";
}
writer.write(')');
}
}