authenticationajaxfilter.java

反向的AJAX。最大的特性是我们成为反向的Ajax。DWR1.x允许你用javascript异步的访问java代码。DWR2.0在这上允许你建立异步java访问javascript代码。 反向的Aj

package org.getahead.dwrdemo.filter;

import java.lang.reflect.Method;

import javax.servlet.http.HttpSession;

import org.directwebremoting.AjaxFilter;
import org.directwebremoting.AjaxFilterChain;
import org.directwebremoting.WebContextFactory;

/**
 * Manages the current Authentication state.
 * @author Joe Walker [joe at getahead dot ltd dot uk]
 */
public class AuthenticationAjaxFilter implements AjaxFilter
{
    /* (non-Javadoc)
     * @see org.directwebremoting.AjaxFilter#doFilter(java.lang.Object, java.lang.reflect.Method, java.lang.Object[], org.directwebremoting.AjaxFilterChain)
     */
    public Object doFilter(Object object, Method method, Object[] params, AjaxFilterChain chain) throws Exception
    {
        // We allow anyone to authenticate
        if (authenticateName.equals(method.getName()))
        {
            return chain.doFilter(object, method, params);
        }

        Object user = getUser();
        if (user != null)
        {
            return chain.doFilter(object, method, params);
        }

        throw new SecurityException("Not authenticated");
    }

    /**
     * @return Returns the authenticateName.
     */
    public String getAuthenticateName()
    {
        return authenticateName;
    }

    /**
     * @param authenticateName The authenticateName to set.
     */
    public void setAuthenticateName(String authenticateName)
    {
        this.authenticateName = authenticateName;
    }

    /**
     * What is the name of the authenticate method?
     */
    private String authenticateName = "authenticate";

    /**
     * Accessor for the current user
     * @param user The current user
     */
    public static void setUser(Object user)
    {
        HttpSession session = WebContextFactory.get().getSession(true);
        session.setAttribute(USER, user);
    }

    /**
     * Accessor for the current user
     * @return The current user
     */
    public static Object getUser()
    {
        HttpSession session = WebContextFactory.get().getSession(true);
        return session.getAttribute(USER);
    }

    /**
     * The session key
     */
    private static final String USER = "org.directwebremoting.filter.AuthenticationAjaxFilter.USER";
}