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package javax.faces.convert;


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


/**
 * <p>{@link Converter} implementation for <code>java.lang.Double</code>
 * (and double primitive) values.</p>
 */

public class DoubleConverter implements Converter {

    // ------------------------------------------------------ Manifest Constants


    /**
     * <p>The standard converter id for this converter.</p>
     */
    public static final String CONVERTER_ID = "javax.faces.Double";

    /**
     * <p>The message identifier of the {@link javax.faces.application.FacesMessage} to be created if
     * the conversion to <code>Double</code> fails.  The message format
     * string for this message may optionally include the following
     * placeholders:
     * <ul>
     * <li><code>{0}</code> replaced by the unconverted value.</li>
     * <li><code>{1}</code> replaced by an example value.</li>
     * <li><code>{2}</code> replaced by a <code>String</code> whose value
     * is the label of the input component that produced this message.</li>
     * </ul></p>
     */
    public static final String DOUBLE_ID =
         "javax.faces.converter.DoubleConverter.DOUBLE";

    /**
     * <p>The message identifier of the {@link javax.faces.application.FacesMessage} to be created if
     * the conversion of the <code>Double</code> value to
     * <code>String</code> fails.   The message format string for this message
     * may optionally include the following placeholders:
     * <ul>
     * <li><code>{0}</code> relaced by the unconverted value.</li>
     * <li><code>{1}</code> replaced by a <code>String</code> whose value
     * is the label of the input component that produced this message.</li>
     * </ul></p>
     */
    public static final String STRING_ID =
         "javax.faces.converter.STRING";

    // ------------------------------------------------------- Converter Methods


    /**
     * @throws ConverterException   {@inheritDoc}
     * @throws NullPointerException {@inheritDoc}
     */
    public Object getAsObject(FacesContext context, UIComponent component,
                              String value) {

        if (context == null || component == null) {
            throw new NullPointerException();
        }

        // If the specified value is null or zero-length, return null
        if (value == null) {
            return (null);
        }
        value = value.trim();
        if (value.length() < 1) {
            return (null);
        }

        try {
            return (Double.valueOf(value));
        } catch (NumberFormatException nfe) {
            throw new ConverterException(MessageFactory.getMessage(
                 context, DOUBLE_ID, value, "1999999",
                 MessageFactory.getLabel(context, component)), nfe);
        } catch (Exception e) {
            throw new ConverterException(e);
        }
    }

    /**
     * @throws ConverterException   {@inheritDoc}
     * @throws NullPointerException {@inheritDoc}
     */
    public String getAsString(FacesContext context, UIComponent component,
                              Object value) {

        if (context == null || component == null) {
            throw new NullPointerException();
        }

        // If the specified value is null, return a zero-length String
        if (value == null) {
            return "";
        }

        // If the incoming value is still a string, play nice
        // and return the value unmodified
        if (value instanceof String) {
            return (String) value;
        }

        try {
            return (Double.toString(((Number) value).doubleValue()));
        } catch (Exception e) {
            throw new ConverterException(MessageFactory.getMessage(
                 context, STRING_ID, value,
                 MessageFactory.getLabel(context, component)), e);
        }
    }
}
