edu.ucsb.adl.middleware
Class QueryServlet

java.lang.Object
  |
  +--javax.servlet.GenericServlet
        |
        +--javax.servlet.http.HttpServlet
              |
              +--edu.ucsb.adl.middleware.QueryServlet

All Implemented Interfaces:

java.io.Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

public final class QueryServlet

extends javax.servlet.http.HttpServlet

HTTP interface to the ADL query service. The query service can be accessed by an HTTP GET or POST request containing one URL-encoded parameter: query, the query to submit. The content type of the return is text/plain with platform-specific encoding, and consists of the query ID followed by a newline.

Service exceptions are caught and returned as HTTP errors. In particular, BadRequestException is mapped to 400 (bad request), NoAuthorizationException is mapped to 403 (forbidden), UnsupportedException is mapped to 501 (not implemented), and InternalErrorException is mapped to 500 (internal server error).

Version:

$Header: /export/home/gjanee/middleware/edu/ucsb/adl/middleware/RCS/QueryServlet.java,v 1.4 2004/03/02 22:01:48 gjanee Exp $

$Log: QueryServlet.java,v $ Revision 1.4 2004/03/02 22:01:48 gjanee
If the middleware_configuration_file servlet initialization parameter is not available, we now look for it as a context-wide initialization parameter.

Revision 1.3 2001/10/04 18:21:31 gjanee
To support the middleware being a web application, we now allow the location of the middleware configuration file to be specified relative to the web application directory.

Revision 1.2 2001/02/15 18:36:46 gjanee
Minor upgrade to servlet API 2.2.

Revision 1.1 2000/04/20 19:44:31 gjanee
Initial revision

Author:

Greg Janée
Alexandria Digital Library

See Also:

Serialized Form

Constructor Summary

QueryServlet()
Creates a QueryServlet.

Method Summary

void	destroy() Frees all resources held by the servlet.
void	doGet(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) HTTP GET interface to the ADL query service.
void	doPost(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) HTTP POST interface to the ADL query service.
void	init(javax.servlet.ServletConfig config) Initializes the servlet.

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doHead, doOptions, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

QueryServlet

public QueryServlet()

Creates a QueryServlet.

Method Detail

init

public void init(javax.servlet.ServletConfig config)
          throws javax.servlet.ServletException

Initializes the servlet.

Specified by:

init in interface javax.servlet.Servlet

Overrides:

init in class javax.servlet.GenericServlet

Parameters:

config - Must contain the following initialization parameter: middleware_configuration_file, the filename of the ADL middleware configuration file. If the filename is not absolute, it is interpreted relative to the middleware web application directory.

Throws:

javax.servlet.UnavailableException - If the initialization fails.

javax.servlet.ServletException

doGet

public void doGet(javax.servlet.http.HttpServletRequest request,
                  javax.servlet.http.HttpServletResponse response)
           throws java.io.IOException

HTTP GET interface to the ADL query service. This method is multithread-safe.

Overrides:

doGet in class javax.servlet.http.HttpServlet

Parameters:

request - The HTTP request.

response - The HTTP response.

Throws:

java.io.IOException - On any I/O error.

doPost

public void doPost(javax.servlet.http.HttpServletRequest request,
                   javax.servlet.http.HttpServletResponse response)
            throws java.io.IOException

HTTP POST interface to the ADL query service. This method is multithread-safe.

Overrides:

doPost in class javax.servlet.http.HttpServlet

Parameters:

request - The HTTP request.

response - The HTTP response.

Throws:

java.io.IOException - On any I/O error.

destroy

public void destroy()

Frees all resources held by the servlet.

Specified by:

destroy in interface javax.servlet.Servlet

Overrides:

destroy in class javax.servlet.GenericServlet