294 lines
13 KiB
Java
294 lines
13 KiB
Java
/*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package javax.servlet;
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import java.io.IOException;
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/**
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* Defines an object that receives requests from the client and sends them to
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* any resource (such as a servlet, HTML file, or JSP file) on the server. The
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* servlet container creates the <code>RequestDispatcher</code> object, which is
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* used as a wrapper around a server resource located at a particular path or
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* given by a particular name.
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*
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* <p>
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* This interface is intended to wrap servlets, but a servlet container can
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* create <code>RequestDispatcher</code> objects to wrap any type of resource.
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*
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* @see ServletContext#getRequestDispatcher(java.lang.String)
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* @see ServletContext#getNamedDispatcher(java.lang.String)
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* @see ServletRequest#getRequestDispatcher(java.lang.String)
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*
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*/
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public interface RequestDispatcher {
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/**
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* The name of the request attribute that should be set by the container
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* when the {@link #forward(ServletRequest, ServletResponse)} method is
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* called. It provides the original value of a path-related property of the
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* request. See the chapter "Forwarded Request Parameters" in the Servlet
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* Specification for details.
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*
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* @since Servlet 3.0
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*/
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static final String FORWARD_REQUEST_URI = "javax.servlet.forward.request_uri";
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/**
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* The name of the request attribute that should be set by the container
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* when the {@link #forward(ServletRequest, ServletResponse)} method is
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* called. It provides the original value of a path-related property of the
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* request. See the chapter "Forwarded Request Parameters" in the Servlet
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* Specification for details.
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*
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* @since Servlet 3.0
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*/
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static final String FORWARD_CONTEXT_PATH = "javax.servlet.forward.context_path";
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/**
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* The name of the request attribute that should be set by the container
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* when the {@link #forward(ServletRequest, ServletResponse)} method is
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* called. It provides the original value of a path-related property of the
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* request. See the chapter "Forwarded Request Parameters" in the Servlet
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* Specification for details.
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*
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* @since Servlet 3.0
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*/
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static final String FORWARD_PATH_INFO = "javax.servlet.forward.path_info";
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/**
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* The name of the request attribute that should be set by the container
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* when the {@link #forward(ServletRequest, ServletResponse)} method is
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* called. It provides the original value of a path-related property of the
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* request. See the chapter "Forwarded Request Parameters" in the Servlet
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* Specification for details.
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*
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* @since Servlet 3.0
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*/
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static final String FORWARD_SERVLET_PATH = "javax.servlet.forward.servlet_path";
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/**
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* The name of the request attribute that should be set by the container
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* when the {@link #forward(ServletRequest, ServletResponse)} method is
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* called. It provides the original value of a path-related property of the
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* request. See the chapter "Forwarded Request Parameters" in the Servlet
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* Specification for details.
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*
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* @since Servlet 3.0
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*/
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static final String FORWARD_QUERY_STRING = "javax.servlet.forward.query_string";
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/**
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* The name of the request attribute that should be set by the container
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* when the {@link #include(ServletRequest, ServletResponse)} method is
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* called on the {@code RequestDispatcher} obtained by a path and not by a
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* name. It provides information on the path that was used to obtain the
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* {@code RequestDispatcher} instance for this include call. See the chapter
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* "Included Request Parameters" in the Servlet Specification for details.
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*
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* @since Servlet 3.0
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*/
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static final String INCLUDE_REQUEST_URI = "javax.servlet.include.request_uri";
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/**
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* The name of the request attribute that should be set by the container
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* when the {@link #include(ServletRequest, ServletResponse)} method is
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* called on the {@code RequestDispatcher} obtained by a path and not by a
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* name. It provides information on the path that was used to obtain the
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* {@code RequestDispatcher} instance for this include call. See the chapter
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* "Included Request Parameters" in the Servlet Specification for details.
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*
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* @since Servlet 3.0
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*/
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static final String INCLUDE_CONTEXT_PATH = "javax.servlet.include.context_path";
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/**
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* The name of the request attribute that should be set by the container
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* when the {@link #include(ServletRequest, ServletResponse)} method is
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* called on the {@code RequestDispatcher} obtained by a path and not by a
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* name. It provides information on the path that was used to obtain the
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* {@code RequestDispatcher} instance for this include call. See the chapter
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* "Included Request Parameters" in the Servlet Specification for details.
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*
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* @since Servlet 3.0
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*/
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static final String INCLUDE_PATH_INFO = "javax.servlet.include.path_info";
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/**
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* The name of the request attribute that should be set by the container
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* when the {@link #include(ServletRequest, ServletResponse)} method is
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* called on the {@code RequestDispatcher} obtained by a path and not by a
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* name. It provides information on the path that was used to obtain the
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* {@code RequestDispatcher} instance for this include call. See the chapter
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* "Included Request Parameters" in the Servlet Specification for details.
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*
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* @since Servlet 3.0
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*/
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static final String INCLUDE_SERVLET_PATH = "javax.servlet.include.servlet_path";
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/**
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* The name of the request attribute that should be set by the container
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* when the {@link #include(ServletRequest, ServletResponse)} method is
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* called on the {@code RequestDispatcher} obtained by a path and not by a
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* name. It provides information on the path that was used to obtain the
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* {@code RequestDispatcher} instance for this include call. See the chapter
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* "Included Request Parameters" in the Servlet Specification for details.
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*
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* @since Servlet 3.0
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*/
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static final String INCLUDE_QUERY_STRING = "javax.servlet.include.query_string";
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/**
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* The name of the request attribute that should be set by the container
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* when custom error-handling servlet or JSP page is invoked. The value of
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* the attribute is of type {@code java.lang.Throwable}. See the chapter
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* "Error Handling" in the Servlet Specification for details.
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*
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* @since Servlet 3.0
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*/
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public static final String ERROR_EXCEPTION = "javax.servlet.error.exception";
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/**
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* The name of the request attribute that should be set by the container
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* when custom error-handling servlet or JSP page is invoked. The value of
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* the attribute is of type {@code java.lang.Class}. See the chapter
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* "Error Handling" in the Servlet Specification for details.
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*
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* @since Servlet 3.0
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*/
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public static final String ERROR_EXCEPTION_TYPE = "javax.servlet.error.exception_type";
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/**
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* The name of the request attribute that should be set by the container
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* when custom error-handling servlet or JSP page is invoked. The value of
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* the attribute is of type {@code java.lang.String}. See the chapter
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* "Error Handling" in the Servlet Specification for details.
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*
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* @since Servlet 3.0
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*/
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public static final String ERROR_MESSAGE = "javax.servlet.error.message";
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/**
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* The name of the request attribute that should be set by the container
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* when custom error-handling servlet or JSP page is invoked. The value of
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* the attribute is of type {@code java.lang.String}. See the chapter
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* "Error Handling" in the Servlet Specification for details.
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*
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* @since Servlet 3.0
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*/
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public static final String ERROR_REQUEST_URI = "javax.servlet.error.request_uri";
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/**
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* The name of the request attribute that should be set by the container
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* when custom error-handling servlet or JSP page is invoked. The value of
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* the attribute is of type {@code java.lang.String}. See the chapter
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* "Error Handling" in the Servlet Specification for details.
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*
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* @since Servlet 3.0
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*/
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public static final String ERROR_SERVLET_NAME = "javax.servlet.error.servlet_name";
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/**
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* The name of the request attribute that should be set by the container
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* when custom error-handling servlet or JSP page is invoked. The value of
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* the attribute is of type {@code java.lang.Integer}. See the chapter
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* "Error Handling" in the Servlet Specification for details.
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*
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* @since Servlet 3.0
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*/
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public static final String ERROR_STATUS_CODE = "javax.servlet.error.status_code";
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/**
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* Forwards a request from a servlet to another resource (servlet, JSP file,
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* or HTML file) on the server. This method allows one servlet to do
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* preliminary processing of a request and another resource to generate the
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* response.
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*
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* <p>
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* For a <code>RequestDispatcher</code> obtained via
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* <code>getRequestDispatcher()</code>, the <code>ServletRequest</code>
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* object has its path elements and parameters adjusted to match the path of
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* the target resource.
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*
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* <p>
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* <code>forward</code> should be called before the response has been
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* committed to the client (before response body output has been flushed).
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* If the response already has been committed, this method throws an
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* <code>IllegalStateException</code>. Uncommitted output in the response
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* buffer is automatically cleared before the forward.
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*
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* <p>
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* The request and response parameters must be either the same objects as
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* were passed to the calling servlet's service method or be subclasses of
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* the {@link ServletRequestWrapper} or {@link ServletResponseWrapper}
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* classes that wrap them.
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*
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*
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* @param request
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* a {@link ServletRequest} object that represents the request
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* the client makes of the servlet
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*
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* @param response
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* a {@link ServletResponse} object that represents the response
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* the servlet returns to the client
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*
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* @exception ServletException
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* if the target resource throws this exception
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*
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* @exception IOException
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* if the target resource throws this exception
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*
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* @exception IllegalStateException
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* if the response was already committed
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*/
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public void forward(ServletRequest request, ServletResponse response)
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throws ServletException, IOException;
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/**
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* Includes the content of a resource (servlet, JSP page, HTML file) in the
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* response. In essence, this method enables programmatic server-side
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* includes.
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*
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* <p>
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* The {@link ServletResponse} object has its path elements and parameters
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* remain unchanged from the caller's. The included servlet cannot change
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* the response status code or set headers; any attempt to make a change is
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* ignored.
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*
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* <p>
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* The request and response parameters must be either the same objects as
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* were passed to the calling servlet's service method or be subclasses of
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* the {@link ServletRequestWrapper} or {@link ServletResponseWrapper}
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* classes that wrap them.
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*
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* @param request
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* a {@link ServletRequest} object that contains the client's
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* request
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*
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* @param response
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* a {@link ServletResponse} object that contains the servlet's
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* response
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*
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* @exception ServletException
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* if the included resource throws this exception
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*
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* @exception IOException
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* if the included resource throws this exception
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*/
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public void include(ServletRequest request, ServletResponse response)
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throws ServletException, IOException;
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}
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