CheckFilter.java Source code

Introduction

Here is the source code for CheckFilter.java

Source

import java.io.IOException;
import java.util.Enumeration;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class CheckFilter implements Filter {

    private FilterConfig config;

    public CheckFilter() {
    }

    public void init(FilterConfig filterConfig) throws ServletException {

        this.config = filterConfig;

    }

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {

        Enumeration params = request.getParameterNames();
        boolean rejected = false;

        while (params.hasMoreElements()) {

            if (isEmpty(request.getParameter((String) params.nextElement()))) {
                reject(request, response);
                rejected = true;
            }

        }

        if (!rejected)
            chain.doFilter(request, response);

    }// doFilter

    private boolean isEmpty(String param) {

        if (param == null || param.length() < 1) {
            return true;
        }

        return false;

    }

    private void reject(ServletRequest request, ServletResponse response) throws IOException, ServletException {

        request.setAttribute("errorMsg", "Please make sure to provide a valid value for all of the text fields.");

        Enumeration params = request.getParameterNames();
        String paramN = null;

        while (params.hasMoreElements()) {

            paramN = (String) params.nextElement();

            request.setAttribute(paramN, request.getParameter(paramN));

        }

        RequestDispatcher dispatcher = request.getRequestDispatcher("/form.jsp");
        dispatcher.forward(request, response);

    }

    public void destroy() {
        /*
         * called before the Filter instance is removed from service by the web
         * container
         */
    }

}