at.porscheinformatik.common.spring.web.extended.locale.LocaleHandlerInterceptor.java Source code

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Here is the source code for at.porscheinformatik.common.spring.web.extended.locale.LocaleHandlerInterceptor.java

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/**
 * Copyright 2014 Daniel Furtlehner 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 at.porscheinformatik.common.spring.web.extended.locale;

import java.util.List;
import java.util.Locale;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.i18n.LocaleContextHolder;
import org.springframework.util.Assert;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import at.porscheinformatik.common.spring.web.extended.util.LocaleUtils;

/**
 * @author Daniel Furtlehner
 */
public class LocaleHandlerInterceptor extends HandlerInterceptorAdapter {

    private List<LocaleSource> sources;
    private List<Locale> availableLocales;

    public LocaleHandlerInterceptor(List<LocaleSource> sources) {
        super();
        Assert.notEmpty(sources, "LocaleSources must not be empty");
        this.sources = sources;
    }

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        for (LocaleSource source : sources) {
            Locale locale = source.getLocale(request, response);

            if (locale != null) {
                LocaleContextHolder.setLocale(locale, true);
                return true;
            }
        }

        // If no Locale is available we simply use the one from the request
        if (availableLocales == null || availableLocales.size() == 0) {
            return true;
        }

        // If no locale was found we check if the one from the request is
        // supported
        Locale locale = LocaleUtils.closestSupportedLocale(availableLocales, LocaleContextHolder.getLocale());
        if (locale != null) {
            LocaleContextHolder.setLocale(locale);
            return true;
        }

        // If the locale from the request is not supported we use the first
        // supported locale
        LocaleContextHolder.setLocale(availableLocales.get(0));

        return true;
    }

    @Autowired
    public void setAvailableLocales(List<Locale> availableLocales) {
        Assert.notNull(availableLocales,
                "No supported locales are configured. Please configure at least one locale");

        this.availableLocales = availableLocales;
    }
}