pt.webdetails.cda.utils.FormulaEvaluator.java Source code

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Here is the source code for pt.webdetails.cda.utils.FormulaEvaluator.java

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/*!
* Copyright 2002 - 2013 Webdetails, a Pentaho company.  All rights reserved.
* 
* This software was developed by Webdetails and is provided under the terms
* of the Mozilla Public License, Version 2.0, or any later version. You may not use
* this file except in compliance with the license. If you need a copy of the license,
* please go to  http://mozilla.org/MPL/2.0/. The Initial Developer is Webdetails.
*
* Software distributed under the Mozilla Public License is distributed on an "AS IS"
* basis, WITHOUT WARRANTY OF ANY KIND, either express or  implied. Please refer to
* the license for the specific language governing your rights and limitations.
*/

package pt.webdetails.cda.utils;

import java.util.ArrayList;

import org.apache.commons.lang.StringUtils;
import org.pentaho.reporting.libraries.formula.Formula;
import org.pentaho.reporting.libraries.formula.FormulaContext;

import pt.webdetails.cda.CdaEngine;
import pt.webdetails.cda.dataaccess.InvalidParameterException;

public class FormulaEvaluator {

    private final static String FORMULA_BEGIN = "${";
    private final static String FORMULA_END = "}";

    public static String replaceFormula(String text) {

        if (!StringUtils.contains(text, FORMULA_BEGIN))
            return text;
        try {
            FormulaContext formulaContext = CdaEngine.getEnvironment().getFormulaContext();

            return replaceFormula(text, formulaContext);

        } catch (Exception e) {//TODO: change
            throw new RuntimeException(e);
        }
    }

    public static String replaceFormula(String text, FormulaContext context) throws InvalidParameterException {
        int startIdx = StringUtils.indexOf(text, FORMULA_BEGIN);
        int contentStartIdx = startIdx + FORMULA_BEGIN.length();

        if (startIdx > -1) {
            int contentEndIdx = StringUtils.lastIndexOf(text, FORMULA_END);
            int endIdx = contentEndIdx + FORMULA_END.length();
            if (contentEndIdx >= contentStartIdx) {
                String contents = StringUtils.substring(text, contentStartIdx, contentEndIdx);

                StringBuilder result = new StringBuilder();
                result.append(StringUtils.substring(text, 0, startIdx));
                result.append(processFormula(contents, context));
                result.append(StringUtils.substring(text, endIdx, text.length()));

                return result.toString();
            }
            //TODO: else throw something
        }
        return text;
    }

    public static Object processFormula(String localValue) throws InvalidParameterException {
        return processFormula(localValue, null);
    }

    public static Object processFormula(String localValue, FormulaContext formulaContext)
            throws InvalidParameterException {
        try {
            Formula formula = new Formula(localValue);

            // set context if available
            if (formulaContext == null) {
                formulaContext = CdaEngine.getEnvironment().getFormulaContext();
            }
            formula.initialize(formulaContext);

            // evaluate
            Object result = formula.evaluate();
            if (result instanceof ArrayList) {//TODO: this returns Object[] with no specific type
                result = ((ArrayList<?>) result).toArray();
            }
            return result;
        } catch (org.pentaho.reporting.libraries.formula.parser.ParseException e) {
            throw new InvalidParameterException("Unable to parse expression " + localValue, e);
        } catch (org.pentaho.reporting.libraries.formula.EvaluationException e) {
            throw new InvalidParameterException("Unable to evaluate expression " + localValue, e);
        }
    }

}