jakarta.servlet.RequestDispatcher Maven / Gradle / Ivy
/*
* Copyright (c) 1997, 2020 Oracle and/or its affiliates and others.
* All rights reserved.
* Copyright 2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jakarta.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 {
/**
* The name of the request attribute under which the original request URI is made available to the target of a
* {@link #forward(ServletRequest,ServletResponse) forward}
*/
static final String FORWARD_REQUEST_URI = "jakarta.servlet.forward.request_uri";
/**
* The name of the request attribute under which the original context path is made available to the target of a
* {@link #forward(ServletRequest,ServletResponse) forward}
*/
static final String FORWARD_CONTEXT_PATH = "jakarta.servlet.forward.context_path";
/**
* The name of the request attribute under which the original {@link jakarta.servlet.http.HttpServletMapping} is made
* available to the target of a {@link #forward(ServletRequest,ServletResponse) forward}
*
* @since 4.0
*/
static final String FORWARD_MAPPING = "jakarta.servlet.forward.mapping";
/**
* The name of the request attribute under which the original path info is made available to the target of a
* {@link #forward(ServletRequest,ServletResponse) forward}
*/
static final String FORWARD_PATH_INFO = "jakarta.servlet.forward.path_info";
/**
* The name of the request attribute under which the original servlet path is made available to the target of a
* {@link #forward(ServletRequest,ServletResponse) forward}
*/
static final String FORWARD_SERVLET_PATH = "jakarta.servlet.forward.servlet_path";
/**
* The name of the request attribute under which the original query string is made available to the target of a
* {@link #forward(ServletRequest,ServletResponse) forward}
*/
static final String FORWARD_QUERY_STRING = "jakarta.servlet.forward.query_string";
/**
* The name of the request attribute under which the request URI of the target of an
* {@link #include(ServletRequest,ServletResponse) include} is stored
*/
static final String INCLUDE_REQUEST_URI = "jakarta.servlet.include.request_uri";
/**
* The name of the request attribute under which the context path of the target of an
* {@link #include(ServletRequest,ServletResponse) include} is stored
*/
static final String INCLUDE_CONTEXT_PATH = "jakarta.servlet.include.context_path";
/**
* The name of the request attribute under which the path info of the target of an
* {@link #include(ServletRequest,ServletResponse) include} is stored
*/
static final String INCLUDE_PATH_INFO = "jakarta.servlet.include.path_info";
/**
* The name of the request attribute under which the {@link jakarta.servlet.http.HttpServletMapping} of the target of an
* {@link #include(ServletRequest,ServletResponse) include} is stored
*/
static final String INCLUDE_MAPPING = "jakarta.servlet.include.mapping";
/**
* The name of the request attribute under which the servlet path of the target of an
* {@link #include(ServletRequest,ServletResponse) include} is stored
*/
static final String INCLUDE_SERVLET_PATH = "jakarta.servlet.include.servlet_path";
/**
* The name of the request attribute under which the query string of the target of an
* {@link #include(ServletRequest,ServletResponse) include} is stored
*/
static final String INCLUDE_QUERY_STRING = "jakarta.servlet.include.query_string";
/**
* The name of the request attribute under which the exception object is propagated during an error dispatch
*/
public static final String ERROR_EXCEPTION = "jakarta.servlet.error.exception";
/**
* The name of the request attribute under which the type of the exception object is propagated during an error dispatch
*/
public static final String ERROR_EXCEPTION_TYPE = "jakarta.servlet.error.exception_type";
/**
* The name of the request attribute under which the exception message is propagated during an error dispatch
*/
public static final String ERROR_MESSAGE = "jakarta.servlet.error.message";
/**
* The name of the request attribute under which the request URI whose processing caused the error is propagated during
* an error dispatch
*/
public static final String ERROR_REQUEST_URI = "jakarta.servlet.error.request_uri";
/**
* The name of the request attribute under which the name of the servlet in which the error occurred is propagated
* during an error dispatch
*/
public static final String ERROR_SERVLET_NAME = "jakarta.servlet.error.servlet_name";
/**
* The name of the request attribute under which the response status is propagated during an error dispatch
*/
public static final String ERROR_STATUS_CODE = "jakarta.servlet.error.status_code";
/**
* 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.
*
*
* This method sets the dispatcher type of the given request to DispatcherType.FORWARD.
*
* @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
*
* @throws ServletException if the target resource throws this exception
*
* @throws IOException if the target resource throws this exception
*
* @throws IllegalStateException if the response was already committed
*
* @see ServletRequest#getDispatcherType
*/
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.
*
*
* This method sets the dispatcher type of the given request to DispatcherType.INCLUDE.
*
* @param request a {@link ServletRequest} object that contains the client's request
*
* @param response a {@link ServletResponse} object that contains the servlet's response
*
* @throws ServletException if the included resource throws this exception
*
* @throws IOException if the included resource throws this exception
*
* @see ServletRequest#getDispatcherType
*/
public void include(ServletRequest request, ServletResponse response) throws ServletException, IOException;
}