SessionCheckFilter

SessionCheckFilter.java

package tld.example.groupid;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InvalidClassException;
import java.io.NotSerializableException;
import java.io.ObjectOutputStream;
import java.util.Enumeration;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

public class SessionCheckFilter
		implements Filter {

	@Override
	public void init(FilterConfig filterConfig)
			throws ServletException {
	}

	@Override
	public void destroy() {
	}

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

		if (request instanceof HttpServletRequest) {
			final HttpServletRequest httpRequest = (HttpServletRequest) request;

			final HttpSession session = httpRequest.getSession(false);

			if (session != null) {
				try {
					final Enumeration<String> attributeNames = session.getAttributeNames();
					while (attributeNames.hasMoreElements()) {
						final String attributeName = attributeNames.nextElement();

						final Object obj = session.getAttribute(attributeName);

						try {
							new ObjectOutputStream(new ByteArrayOutputStream()).writeObject(obj);

						} catch (final InvalidClassException ice) {
							System.out.println("InvalidClassException for Session Object " + attributeName);
							ice.printStackTrace();

						} catch (final NotSerializableException nse) {
							System.out.println("NotSerializableException for Session Object " + attributeName);
							nse.printStackTrace();

						} catch (final IOException ioe) {
							System.out.println("IOException for Session Object " + attributeName);
							ioe.printStackTrace();
						}
					}

				} catch (final Exception e) {
					e.printStackTrace();
				}
			}
		}

		chain.doFilter(request, response);
	}

}