javax.servlet.RequestDispatcher Maven / Gradle / Ivy
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* as indicated by the @author tags. See the copyright.txt file in the
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*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package javax.servlet;
import java.io.IOException;
/**
* Defines an object that receives requests from the client and sends them to
* any resource (such as a servlet, HTML file, or JSP file) on the server. The
* servlet container creates the RequestDispatcher object, which
* is used as a wrapper around a server resource located at a particular path or
* given by a particular name.
*
* This interface is intended to wrap servlets, but a servlet container can
* create RequestDispatcher objects to wrap any type of resource.
*
* @author Various
* @see ServletContext#getRequestDispatcher(java.lang.String)
* @see ServletContext#getNamedDispatcher(java.lang.String)
* @see ServletRequest#getRequestDispatcher(java.lang.String)
*/
public interface RequestDispatcher
{
/**
* Forwards a request from a servlet to another resource (servlet, JSP file,
* or HTML file) on the server. This method allows one servlet to do
* preliminary processing of a request and another resource to generate the
* response.
*
* For a RequestDispatcher obtained via
* getRequestDispatcher(), the ServletRequest
* object has its path elements and parameters adjusted to match the path of
* the target resource.
*
* forward should be called before the response has been
* committed to the client (before response body output has been flushed). If
* the response already has been committed, this method throws an
* IllegalStateException. Uncommitted output in the response
* buffer is automatically cleared before the forward.
*
* The request and response parameters must be either the same objects as
* were passed to the calling servlet's service method or be subclasses of
* the {@link ServletRequestWrapper} or {@link ServletResponseWrapper}
* classes that wrap them.
*
* @param request
* a {@link ServletRequest} object that represents the request the
* client makes of the servlet
* @param response
* a {@link ServletResponse} object that represents the response
* the servlet returns to the client
* @exception ServletException
* if the target resource throws this exception
* @exception IOException
* if the target resource throws this exception
* @exception IllegalStateException
* if the response was already committed
*/
public void forward(ServletRequest request, ServletResponse response) throws ServletException, IOException;
/**
* Includes the content of a resource (servlet, JSP page, HTML file) in the
* response. In essence, this method enables programmatic server-side
* includes.
*
* The {@link ServletResponse} object has its path elements and parameters
* remain unchanged from the caller's. The included servlet cannot change the
* response status code or set headers; any attempt to make a change is
* ignored.
*
* The request and response parameters must be either the same objects as
* were passed to the calling servlet's service method or be subclasses of
* the {@link ServletRequestWrapper} or {@link ServletResponseWrapper}
* classes that wrap them.
*
* @param request
* a {@link ServletRequest} object that contains the client's
* request
* @param response
* a {@link ServletResponse} object that contains the servlet's
* response
* @exception ServletException
* if the included resource throws this exception
* @exception IOException
* if the included resource throws this exception
*/
public void include(ServletRequest request, ServletResponse response) throws ServletException, IOException;
}