org.sakaiproject.tool.assessment.jsf.validator.FinQuestionValidator.java Source code

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Here is the source code for org.sakaiproject.tool.assessment.jsf.validator.FinQuestionValidator.java

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/**********************************************************************************
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 *
 * Copyright (c) 2004, 2005, 2006, 2008 The Sakai Foundation
 *
 * Licensed under the Educational Community License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.opensource.org/licenses/ECL-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
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package org.sakaiproject.tool.assessment.jsf.validator;

import java.math.BigDecimal;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Locale;
import java.util.StringTokenizer;

import javax.faces.application.FacesMessage;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.validator.Validator;
import javax.faces.validator.ValidatorException;

import org.apache.commons.math.complex.Complex;
import org.apache.commons.math.complex.ComplexFormat;
import org.sakaiproject.tool.assessment.ui.listener.util.ContextUtil;

public class FinQuestionValidator implements Validator {

    public FinQuestionValidator() {
        // TODO Auto-generated constructor stub
    }

    public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {

        String text = (String) value;
        text = text.replaceAll("\\s+", "").replace(',', '.'); // in Spain, comma is used as a decimal point     

        int i = text.indexOf("{", 0);
        int j = text.indexOf("}", 0);

        while (i != -1 && j > i) {
            String number = text.substring(i + 1, j);

            StringTokenizer st = new StringTokenizer(number, "|");

            if (st.countTokens() > 1) {
                String number1 = st.nextToken().trim();
                String number2 = st.nextToken().trim();

                // The first value in range must have a valid format
                if (!isRealNumber(number1)) {
                    String error = (String) ContextUtil.getLocalizedString(
                            "org.sakaiproject.tool.assessment.bundle.DeliveryMessages",
                            "fin_invalid_characters_error");
                    throw new ValidatorException(new FacesMessage(error));
                }

                // The second value in range must have a valid format
                if (!isRealNumber(number2)) {
                    String error = (String) ContextUtil.getLocalizedString(
                            "org.sakaiproject.tool.assessment.bundle.DeliveryMessages",
                            "fin_invalid_characters_error");
                    throw new ValidatorException(new FacesMessage(error));
                }

                // The range must be in increasing order
                BigDecimal rango1 = new BigDecimal(number1);
                BigDecimal rango2 = new BigDecimal(number2);
                if (rango1.compareTo(rango2) != -1) {
                    String error = (String) ContextUtil.getLocalizedString(
                            "org.sakaiproject.tool.assessment.bundle.DeliveryMessages",
                            "fin_invalid_characters_error");
                    throw new ValidatorException(new FacesMessage(error));
                }
            } else {
                // The number can be in a decimal format or complex format
                if (!isRealNumber(number) && !isComplexNumber(number)) {
                    String error = (String) ContextUtil.getLocalizedString(
                            "org.sakaiproject.tool.assessment.bundle.DeliveryMessages",
                            "fin_invalid_characters_error");
                    throw new ValidatorException(new FacesMessage(error));
                }
            }

            i = text.indexOf("{", i + 1);
            if (j + 1 < text.length())
                j = text.indexOf("}", j + 1);
            else
                j = -1;
        }

    }

    static boolean isComplexNumber(String value) {

        boolean isComplex = true;
        Complex complex = null;
        try {
            DecimalFormat df = (DecimalFormat) NumberFormat.getNumberInstance(Locale.US);
            df.setGroupingUsed(false);

            // Numerical format ###.## (decimal symbol is the point)
            ComplexFormat complexFormat = new ComplexFormat(df);
            complex = complexFormat.parse(value);

            // This is because there is a bug parsing complex number. 9i is parsed as 9
            if (complex.getImaginary() == 0 && value.contains("i"))
                isComplex = false;
        } catch (Exception e) {
            isComplex = false;
        }

        return isComplex;
    }

    static boolean isRealNumber(String value) {

        boolean isReal = true;
        try {
            // Number has decimal format? If no, Exception is throw
            new BigDecimal(value);

        } catch (Exception e) {
            isReal = false;
        }

        return isReal;
    }

}