/*
 ***************************************************************************************
 *  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;

/**
 * Concatenation expression that concatenates the result of child expressions to the expression.
 */
public class ConcatExpression extends ExpressionBase {
    private static final long serialVersionUID = 0L;

    /**
     * Ctor.
     */
    public ConcatExpression() {
    }

    /**
     * Add a constant to include in the computation.
     *
     * @param object constant to add
     * @return expression
     */
    public ConcatExpression 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 ConcatExpression 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 ConcatExpression add(String propertyName) {
        this.getChildren().add(new PropertyValueExpression(propertyName));
        return this;
    }

    public ExpressionPrecedenceEnum getPrecedence() {
        return ExpressionPrecedenceEnum.CONCAT;
    }

    public void toPrecedenceFreeEPL(StringWriter writer) {
        String delimiter = "";
        for (Expression child : this.getChildren()) {
            writer.write(delimiter);
            child.toEPL(writer, getPrecedence());
            delimiter = "||";
        }
    }
}