/*
 * Copyright 2000-2016 Vaadin Ltd.
 *
 * Licensed 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 com.vaadin.data.util.converter;

import java.text.NumberFormat;
import java.util.Locale;

import com.vaadin.data.Result;

/**
 * A converter that converts from {@link String} to {@link Long} and back. Uses
 * the given locale and a {@link NumberFormat} instance for formatting and
 * parsing.
 * <p>
 * Override and overwrite {@link #getFormat(Locale)} to use a different format.
 * </p>
 *
 * @author Vaadin Ltd
 * @since 8.0
 */
public class StringToLongConverter
        extends AbstractStringToNumberConverter<Long> {

    /**
     * Returns the format used by {@link #convertToPresentation(Long, Locale)}
     * and {@link #convertToModel(String, Locale)}.
     *
     * @param locale
     *            The locale to use
     * @return A NumberFormat instance
     */
    @Override
    protected NumberFormat getFormat(Locale locale) {
        if (locale == null) {
            locale = Locale.getDefault();
        }
        return NumberFormat.getIntegerInstance(locale);
    }

    @Override
    public Result<Long> convertToModel(String value, Locale locale) {
        Number n = convertToNumber(value, locale);
        return n == null ? Result.ok(null) : Result.ok(n.longValue());

    }

}