biz.letsweb.lukasfloorspring.interceptors.MobileInterceptor.java Source code

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Here is the source code for biz.letsweb.lukasfloorspring.interceptors.MobileInterceptor.java

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package biz.letsweb.lukasfloorspring.interceptors;

/**
 * Copyright (c) 2010 Mark S. Kolich http://mark.koli.ch
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
 * associated documentation files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
 * NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

public class MobileInterceptor extends HandlerInterceptorAdapter {

    /**
     * The name of the mobile view that the viewer is re-directed to in the event that a mobile device
     * is detected.
     */
    private static final String MOBILE_VIEWER_VIEW_NAME = "mobile";

    /**
     * The User-Agent Http header.
     */
    private static final String USER_AGENT_HEADER = "User-Agent";

    private List<String> mobileAgents;
    private List<Pattern> agentPatterns;

    public void init() {
        agentPatterns = new ArrayList<>();
        // Pre-compile the user-agent patterns as specified in mvc.xml
        for (final String ua : mobileAgents) {
            try {
                agentPatterns.add(Pattern.compile(ua, Pattern.CASE_INSENSITIVE));
            } catch (PatternSyntaxException e) {
                // Ignore the pattern, if it failed to compile
                // for whatever reason.
            }
        }
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView model) throws Exception {
        final String userAgent = request.getHeader(USER_AGENT_HEADER);
        if (userAgent != null) {
            // If the User-Agent matches a mobile device, then we set
            // the view name to the mobile view JSP so that a mobile
            // JSP is rendered instead of a normal view.
            if (isMobile(userAgent)) {
                if (model == null) {
                } else {
                    final String view = model.getViewName();
                    model.setViewName(view + "-" + MOBILE_VIEWER_VIEW_NAME);
                }
            }
        }
    }

    /**
     * Returns true of the given User-Agent string matches a suspected mobile device.
     * 
     * @param agent
     * @return
     */
    private final boolean isMobile(final String agent) {
        boolean mobile = false;
        for (final Pattern p : agentPatterns) {
            final Matcher m = p.matcher(agent);
            if (m.find()) {
                mobile = true;
                break;
            }
        }
        return mobile;
    }

    public void setMobileUserAgents(List<String> agents) {
        mobileAgents = agents;
    }

}