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The public API classes of the Apache MyFaces CORE JSF-2.2 project
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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache 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.apache.org/licenses/LICENSE-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.
 */
package javax.faces.convert;

import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;

import org.apache.myfaces.buildtools.maven2.plugin.builder.annotation.JSFConverter;

import java.text.DecimalFormat;
import java.text.DecimalFormatSymbols;
import java.text.NumberFormat;
import java.text.ParseException;
import java.util.Locale;

/**
 * see Javadoc of JSF Specification
 *
 * @author Thomas Spiegl (latest modification by $Author: lu4242 $)
 * @version $Revision: 1068711 $ $Date: 2011-02-08 19:48:23 -0500 (Tue, 08 Feb 2011) $
 */
@JSFConverter
public class DoubleConverter
        implements Converter
{
    // API FIELDS
    public static final String CONVERTER_ID = "javax.faces.Double";
    public static final String STRING_ID = "javax.faces.converter.STRING";
    public static final String DOUBLE_ID = "javax.faces.converter.DoubleConverter.DOUBLE";

    // CONSTRUCTORS
    public DoubleConverter()
    {
    }

    // METHODS
    public Object getAsObject(FacesContext facesContext, UIComponent uiComponent, String value)
    {
        if (facesContext == null) throw new NullPointerException("facesContext");
        if (uiComponent == null) throw new NullPointerException("uiComponent");

        if (value != null)
        {
            value = value.trim();
            if (value.length() > 0)
            {
                try
                {
                    value = fixLocale(facesContext, value);
                    return this.stringToDouble(value);
                }
                catch (NumberFormatException e)
                {
                    throw new ConverterException(_MessageUtils.getErrorMessage(facesContext,
                                                                               DOUBLE_ID,
                                                                               new Object[]{value,"4214",_MessageUtils.getLabel(facesContext, uiComponent)}), e);
                }

            }
        }
        return null;
    }

    /**
     * Since Double.valueOf is not Locale aware, and NumberFormatter
     * cannot parse E values correctly, we need to make a US Locale
     * string from our input value.
     * E.g. '34,383e3' will be translated to '34.383e3' if Locale.DE
     * is set in the {@link javax.faces.component.UIViewRoot#getLocale()}
     *
     * @param facesContext
     * @param value
     * @return the 'fixed' value String
     */
    private String fixLocale(FacesContext facesContext, String value)
    {
        Locale loc = facesContext.getViewRoot().getLocale();
        if (loc == null || loc == Locale.US)
        {
            // nothing to fix if we are already using the US Locale
            return value;
        }

        // TODO: DecimalFormatSymbols.getInstance exists only on JDK 1.6
        // change it on JSF 2.1
        //DecimalFormatSymbols dfs = DecimalFormatSymbols.getInstance(loc);
        DecimalFormatSymbols dfs = new DecimalFormatSymbols(loc);

        char decSep   = dfs.getDecimalSeparator();


        // replace decimal separators which are different to '.'
        if (decSep != '.' && value.lastIndexOf(decSep) >= 0)
        {
            StringBuffer sbVal = new StringBuffer();

            // remove all groupSeperators and change the decimalSeperator
            for (int i = 0; i < value.length(); i++)
            {
                if (value.charAt(i) == decSep)
                {
                    sbVal.append('.'); // we append the Locale.US decimal separator
                    continue;
                }

                // just append all other characters as usual
                sbVal.append(value.charAt(i));
            }

            value = sbVal.toString();
        }

        // we need the formatter with the correct Locale of the user
        return value;
    }

    private Double stringToDouble(String value)
    {
        // this is a special hack for a jvm vulnerability with
        // converting some special double values.
        // e.g. "2.225073858507201200000e-308"
        // see MYFACES-3024 for further information
        // TODO we can remove this hack, once this got fixed in the jvm!
        if (value.length() >= 23)
        {
            StringBuffer normalized = new StringBuffer();
            for (int i=0; i< value.length(); i++)
            {
                char c = value.charAt(i);
                if ( c != '.')
                {
                    normalized.append(c);
                }
            }

            String normalizedString = normalized.toString();
            if (normalizedString.contains("22250738585072012") && normalizedString.contains("e-"))
            {
                // oops, baaad value!
               throw new NumberFormatException("Not Allowed! This value could possibly kill the VM!");
            }
        }


        return Double.valueOf(value);
    }

    public String getAsString(FacesContext facesContext, UIComponent uiComponent, Object value)
    {
        if (facesContext == null) throw new NullPointerException("facesContext");
        if (uiComponent == null) throw new NullPointerException("uiComponent");

        if (value == null)
        {
            return "";
        }
        if (value instanceof String)
        {
            return (String)value;
        }
        try
        {
            return Double.toString(((Number)value).doubleValue());
        }
        catch (Exception e)
        {
            throw new ConverterException(_MessageUtils.getErrorMessage(facesContext, STRING_ID, new Object[]{value,_MessageUtils.getLabel(facesContext, uiComponent)}),e);
        }
    }
}