001 package com.croftsoft.core.servlet;
002
003 import java.io.*;
004
005 import javax.servlet.*;
006 import javax.servlet.http.*;
007
008 import com.croftsoft.core.io.Encoder;
009 import com.croftsoft.core.io.Parser;
010 import com.croftsoft.core.role.Server;
011
012 /*********************************************************************
013 * Relays HTTP requests to a Server.
014 *
015 * @version
016 * $Id: HttpGatewayServlet.java,v 1.2 2006/11/28 01:31:07 croft Exp $
017 * @since
018 * 2003-05-13
019 * @author
020 * <a href="https://www.croftsoft.com/">David Wallace Croft</a>
021 *********************************************************************/
022
023 public abstract class HttpGatewayServlet
024 extends HttpServlet
025 //////////////////////////////////////////////////////////////////////
026 //////////////////////////////////////////////////////////////////////
027 {
028
029 private final Server server;
030
031 private final Parser parser;
032
033 private final Encoder encoder;
034
035 //////////////////////////////////////////////////////////////////////
036 // protected and public constructor methods
037 //////////////////////////////////////////////////////////////////////
038
039 protected HttpGatewayServlet (
040 Server server,
041 Parser parser,
042 Encoder encoder )
043 //////////////////////////////////////////////////////////////////////
044 {
045 this.server = server;
046
047 this.parser = parser;
048
049 this.encoder = encoder;
050 }
051
052 public HttpGatewayServlet ( )
053 //////////////////////////////////////////////////////////////////////
054 {
055 this ( ( Server ) null, ( Parser ) null, ( Encoder ) null );
056 }
057
058 //////////////////////////////////////////////////////////////////////
059 // protected Encoder/Parser/Server methods that may be overridden
060 //////////////////////////////////////////////////////////////////////
061
062 protected byte [ ] encode ( Object object )
063 throws IOException
064 //////////////////////////////////////////////////////////////////////
065 {
066 return encoder.encode ( object );
067 }
068
069 protected Object parse (
070 InputStream inputStream,
071 int contentLength )
072 throws IOException
073 //////////////////////////////////////////////////////////////////////
074 {
075 return parser.parse ( inputStream, contentLength );
076 }
077
078 protected Object serve ( Object request )
079 //////////////////////////////////////////////////////////////////////
080 {
081 return server.serve ( request );
082 }
083
084 //////////////////////////////////////////////////////////////////////
085 // public final service method
086 //////////////////////////////////////////////////////////////////////
087
088 @Override
089 public final void service (
090 HttpServletRequest httpServletRequest,
091 HttpServletResponse httpServletResponse )
092 throws IOException, ServletException
093 //////////////////////////////////////////////////////////////////////
094 {
095 try
096 {
097 Object request = null;
098
099 try
100 {
101 request = parse (
102 httpServletRequest.getInputStream ( ), -1 );
103 }
104 catch ( IOException ex )
105 {
106 httpServletResponse.setStatus (
107 HttpServletResponse.SC_BAD_REQUEST );
108 }
109
110 if ( request != null )
111 {
112 Object response = serve ( request );
113
114 if ( response != null )
115 {
116 httpServletResponse.setStatus ( HttpServletResponse.SC_OK );
117
118 byte [ ] bytes = encode ( response );
119
120 httpServletResponse.getOutputStream ( ).write ( bytes );
121 }
122 else
123 {
124 httpServletResponse.setStatus (
125 HttpServletResponse.SC_ACCEPTED );
126 }
127 }
128 }
129 catch ( Exception ex )
130 {
131 httpServletResponse.setStatus (
132 HttpServletResponse.SC_INTERNAL_SERVER_ERROR );
133
134 log ( ex.getMessage ( ), ex );
135 }
136 }
137
138 //////////////////////////////////////////////////////////////////////
139 //////////////////////////////////////////////////////////////////////
140 }