app/src/main/java/org/apache/roller/weblogger/ui/rendering/filters/DeviceResolverRequestFilter.java

/*
 * Copyright 2010-2014 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.
 */
/*
 * Code from Spring Mobile and modified for use in Apache Roller
 * https://github.com/spring-projects/spring-mobile 11 Feb 2014
 * 
 */

package org.apache.roller.weblogger.ui.rendering.filters;

import java.io.IOException;

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

import org.apache.roller.weblogger.ui.rendering.util.mobile.Device;
import org.apache.roller.weblogger.ui.rendering.util.mobile.DeviceResolver;
import org.apache.roller.weblogger.ui.rendering.util.mobile.DeviceUtils;
import org.apache.roller.weblogger.ui.rendering.util.mobile.LiteDeviceResolver;
import org.springframework.web.filter.OncePerRequestFilter;

/**
 * A Servlet 2.3 Filter that resolves the Device that originated the web
 * request. The resolved Device is exported as a request attribute under the
 * well-known name of {@link DeviceUtils#CURRENT_DEVICE_ATTRIBUTE}. Request
 * handlers such as @Controllers and views may then access the currentDevice to
 * vary their control and rendering logic, respectively.
 * 
 * <!-- Spring-mobile based device type resolver --> <filter>
 * <filter-name>DeviceResolverRequestFilter</filter-name>
 * <filter-class>org.apache
 * .roller.weblogger.ui.rendering.filters.DeviceResolverRequestFilter
 * </filter-class> </filter>
 * 
 * <!-- Mobile device detection (Once per request)--> <filter-mapping>
 * <filter-name>DeviceResolverRequestFilter</filter-name>
 * <url-pattern>/*</url-pattern> <dispatcher>REQUEST</dispatcher>
 * </filter-mapping>
 * 
 * @author Roy Clarkson
 */
public class DeviceResolverRequestFilter extends OncePerRequestFilter {

    private final DeviceResolver deviceResolver;

    /**
     * Create a device resolving {@link Filter} that defaults to a
     * {@link LiteDeviceResolver} implementation.
     */
    public DeviceResolverRequestFilter() {
        this(new LiteDeviceResolver());
    }

    /**
     * Create a device resolving {@link Filter}.
     * 
     * @param deviceResolver
     *            the device resolver to delegate to.
     */
    public DeviceResolverRequestFilter(DeviceResolver deviceResolver) {
        this.deviceResolver = deviceResolver;
    }

    /**
     * @see org.springframework.web.filter.OncePerRequestFilter#doFilterInternal(javax.servlet.http.HttpServletRequest,
     *      javax.servlet.http.HttpServletResponse, javax.servlet.FilterChain)
     */
    @Override
    protected void doFilterInternal(HttpServletRequest request,
            HttpServletResponse response, FilterChain filterChain)
            throws ServletException, IOException {
        Device device = deviceResolver.resolveDevice(request);
        request.setAttribute(DeviceUtils.CURRENT_DEVICE_ATTRIBUTE, device);
        filterChain.doFilter(request, response);
    }

}