/*
 * The TMC source file
 * Copyright ® 2005 Beijing Topsec Network Security Technology Co.,Ltd
 * All right reserved.
 */
package com.test.common;

import java.io.IOException;

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 sun.rmi.transport.proxy.HttpReceiveSocket;

/**
 * 
 * Filter that sets the character encoding to be used in parsing the
 * 
 * incoming request, either unconditionally or only if the client did not
 * 
 * specify a character encoding. Configuration of this filter is based on
 * 
 * the following initialization parameters:
 * 
 * 
 * 
 * encoding - The character encoding to be configured for this request, either conditionally or
 * unconditionally based on
 * 
 * the ignore initialization parameter. This parameter
 * 
 * is required, so there is no default.
 * 
 * ignore - If set to "true", any character encoding specified by the client is ignored, and the
 * value returned by the
 * 
 * selectEncoding() method is set. If set to "false,
 * 
 * selectEncoding() is called only if the
 * 
 * client has not already specified an encoding. By default, this
 * 
 * parameter is set to "true".
 * 
 * 
 * 
 * 
 * 
 * Although this filter can be used unchanged, it is also easy to
 * 
 * subclass it and make the selectEncoding() method more
 * 
 * intelligent about what encoding to choose, based on characteristics of
 * 
 * the incoming request (such as the values of the Accept-Language
 * 
 * and User-Agent headers, or a value stashed in the current
 * 
 * user′s session.
 * 
 * 
 *  
 */

public class EncodingFilter implements Filter {

    // ----------------------------------------------------- Instance Variables

    /**
     * 
     * The default character encoding to set for requests that pass through
     * 
     * this filter.
     *  
     */

    protected String encoding = null;
    
    protected String getEncoding = null;

    /**
     * 
     * The filter configuration object we are associated with. If this value
     * 
     * is null, this filter instance is not currently configured.
     *  
     */

    protected FilterConfig filterConfig = null;

    /**
     * 
     * Should a character encoding specified by the client be ignored?
     *  
     */

    protected boolean ignore = true;

    // --------------------------------------------------------- Public Methods

    /**
     * 
     * Take this filter out of service.
     *  
     */

    public void destroy() {

        this.encoding = null;

        this.filterConfig = null;

        this.getEncoding = null;
    }

    /**
     * 
     * Select and set (if specified) the character encoding to be used to
     * 
     * interpret request parameters for this request.
     * 
     * 
     * 
     * @param request
     *            The servlet request we are processing
     * 
     * @param result
     *            The servlet response we are creating
     * 
     * @param chain
     *            The filter chain we are processing
     * 
     * 
     * 
     * @exception IOException
     *                if an input/output error occurs
     * 
     * @exception ServletException
     *                if a servlet error occurs
     *  
     */

    public void doFilter(ServletRequest request, ServletResponse response,

    FilterChain chain)

    throws IOException, ServletException {

        // Conditionally select and set the character encoding to be used

        if (ignore || (request.getCharacterEncoding() == null)) {

            String encoding = selectEncoding(request);

            if (encoding != null)

                request.setCharacterEncoding(encoding);

        }

        // Pass control on to the next filter

        chain.doFilter(request, response);

    }

    /**
     * 
     * Place this filter into service.
     * 
     * 
     * 
     * @param filterConfig
     *            The filter configuration object
     *  
     */

    public void init(FilterConfig filterConfig) throws ServletException {

        this.filterConfig = filterConfig;

        this.encoding = filterConfig.getInitParameter("encoding");
        
        this.getEncoding = filterConfig.getInitParameter("getEncoding");

        String value = filterConfig.getInitParameter("ignore");

        if (value == null)

            this.ignore = true;

        else if (value.equalsIgnoreCase("true"))

            this.ignore = true;

        else if (value.equalsIgnoreCase("yes"))

            this.ignore = true;

        else

            this.ignore = false;

    }

    // ------------------------------------------------------ Protected Methods

    /**
     * 
     * Select an appropriate character encoding to be used, based on the
     * 
     * characteristics of the current request and/or filter initialization
     * 
     * parameters. If no character encoding should be set, return
     * 
     * null.
     * 
     * 
     * 
     * 
     * The default implementation unconditionally returns the value configured
     * 
     * by the encoding initialization parameter for this
     * 
     * filter.
     * 
     * 
     * 
     * @param request
     *            The servlet request we are processing
     *  
     */

    protected String selectEncoding(ServletRequest request) {

    	if (request instanceof HttpServletRequest) {
			HttpServletRequest req = (HttpServletRequest) request;
			if("get".equalsIgnoreCase(req.getMethod())){
				return (this.getEncoding);
			}
		}
        return (this.encoding);

    }

}//EOC