Spring Framework example source code file (ThemeChangeInterceptor.java)

This example Spring Framework source code file (ThemeChangeInterceptor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Spring Framework tags/keywords

default_param_name, default_param_name, dispatcherservlet, handlerinterceptoradapter, http, illegalstateexception, no, object, request, response, servlet, servletexception, servletexception, string, string, themechangeinterceptor, themeresolver, themeresolver

The Spring Framework ThemeChangeInterceptor.java source code

/*
 * Copyright 2002-2005 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
 * limitations under the License.
 */

package org.springframework.web.servlet.theme;

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

import org.springframework.web.servlet.ThemeResolver;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
import org.springframework.web.servlet.support.RequestContextUtils;

/**
 * Interceptor that allows for changing the current theme on every request,
 * via a configurable request parameter.
 *
 * @author Juergen Hoeller
 * @since 20.06.2003
 * @see org.springframework.web.servlet.ThemeResolver
 */
public class ThemeChangeInterceptor extends HandlerInterceptorAdapter {

	/**
	 * Default name of the theme specification parameter: "theme".
	 */
	public static final String DEFAULT_PARAM_NAME = "theme";

	private String paramName = DEFAULT_PARAM_NAME;


	/**
	 * Set the name of the parameter that contains a theme specification
	 * in a theme change request. Default is "theme".
	 */
	public void setParamName(String paramName) {
		this.paramName = paramName;
	}


	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws ServletException {

		ThemeResolver themeResolver = RequestContextUtils.getThemeResolver(request);
		if (themeResolver == null) {
			throw new IllegalStateException("No ThemeResolver found: not in a DispatcherServlet request?");
		}
		String newTheme = request.getParameter(this.paramName);
		if (newTheme != null) {
			themeResolver.setThemeName(request, response, newTheme);
		}
		// Proceed in any case.
		return true;
	}

}