/*
 * Copyright 2002-2017 the original author or authors.
 *
 * 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
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package org.springframework.web.server.i18n;

import org.springframework.context.i18n.LocaleContext;
import org.springframework.lang.Nullable;
import org.springframework.web.server.ServerWebExchange;

Interface for web-based locale context resolution strategies that allows
for both locale context resolution via the request and locale context modification
via the HTTP exchange.
The LocaleContext object can potentially includes associated time zone and other locale related information. 
Author:
Sebastien Deleuze
See Also:
LocaleContext
Since:
5.0/**
 * Interface for web-based locale context resolution strategies that allows
 * for both locale context resolution via the request and locale context modification
 * via the HTTP exchange.
 *
 * <p>The {@link org.springframework.context.i18n.LocaleContext} object can potentially
 * includes associated time zone and other locale related information.
 *
 * @author Sebastien Deleuze
 * @since 5.0
 * @see LocaleContext
 */
public interface LocaleContextResolver {

	
Resolve the current locale context via the given exchange.
The returned context may be a TimeZoneAwareLocaleContext, containing a locale with associated time zone information. Simply apply an instanceof check and downcast accordingly. 
Custom resolver implementations may also return extra settings in
the returned context, which again can be accessed through downcasting.
Params:
exchange – current server exchange
Returns:
the current locale context (never null)/**
	 * Resolve the current locale context via the given exchange.
	 * <p>The returned context may be a
	 * {@link org.springframework.context.i18n.TimeZoneAwareLocaleContext},
	 * containing a locale with associated time zone information.
	 * Simply apply an {@code instanceof} check and downcast accordingly.
	 * <p>Custom resolver implementations may also return extra settings in
	 * the returned context, which again can be accessed through downcasting.
	 * @param exchange current server exchange
	 * @return the current locale context (never {@code null})
	 */
	LocaleContext resolveLocaleContext(ServerWebExchange exchange);

	
Set the current locale context to the given one,
potentially including a locale with associated time zone information.
Params:
exchange – current server exchange
localeContext – the new locale context, or null to clear the locale
Throws:
UnsupportedOperationException – if the LocaleResolver implementation
does not support dynamic changing of the locale or time zone
See Also:
SimpleLocaleContext
SimpleTimeZoneAwareLocaleContext/**
	 * Set the current locale context to the given one,
	 * potentially including a locale with associated time zone information.
	 * @param exchange current server exchange
	 * @param localeContext the new locale context, or {@code null} to clear the locale
	 * @throws UnsupportedOperationException if the LocaleResolver implementation
	 * does not support dynamic changing of the locale or time zone
	 * @see org.springframework.context.i18n.SimpleLocaleContext
	 * @see org.springframework.context.i18n.SimpleTimeZoneAwareLocaleContext
	 */
	void setLocaleContext(ServerWebExchange exchange, @Nullable LocaleContext localeContext);

}