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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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
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package javax.servlet;

import java.io.BufferedReader;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Locale;
import java.util.Map;



/**
 * Defines an object to provide client request information to a servlet.  The
 * servlet container creates a ServletRequest object and passes
 * it as an argument to the servlet's service method.
 *
 * 

A ServletRequest object provides data including * parameter name and values, attributes, and an input stream. * Interfaces that extend ServletRequest can provide * additional protocol-specific data (for example, HTTP data is * provided by {@link javax.servlet.http.HttpServletRequest}. * * @author Various * @version $Version$ * * @see javax.servlet.http.HttpServletRequest * */ public interface ServletRequest { /** * * Returns the value of the named attribute as an Object, * or null if no attribute of the given name exists. * *

Attributes can be set two ways. The servlet container may set * attributes to make available custom information about a request. * For example, for requests made using HTTPS, the attribute * javax.servlet.request.X509Certificate can be used to * retrieve information on the certificate of the client. Attributes * can also be set programatically using * {@link ServletRequest#setAttribute}. This allows information to be * embedded into a request before a {@link RequestDispatcher} call. * *

Attribute names should follow the same conventions as package * names. This specification reserves names matching java.*, * javax.*, and sun.*. * * @param name a String specifying the name of * the attribute * * @return an Object containing the value * of the attribute, or null if * the attribute does not exist * */ public Object getAttribute(String name); /** * Returns an Enumeration containing the * names of the attributes available to this request. * This method returns an empty Enumeration * if the request has no attributes available to it. * * * @return an Enumeration of strings * containing the names * of the request's attributes * */ public Enumeration getAttributeNames(); /** * Returns the name of the character encoding used in the body of this * request. This method returns null if the request * does not specify a character encoding * * * @return a String containing the name of * the character encoding, or null * if the request does not specify a character encoding * */ public String getCharacterEncoding(); /** * Overrides the name of the character encoding used in the body of this * request. This method must be called prior to reading request parameters * or reading input using getReader(). * * * @param env a String containing the name of * the character encoding. * @throws java.io.UnsupportedEncodingException if this is not a valid encoding */ public void setCharacterEncoding(String env) throws java.io.UnsupportedEncodingException; /** * Returns the length, in bytes, of the request body * and made available by the input stream, or -1 if the * length is not known. For HTTP servlets, same as the value * of the CGI variable CONTENT_LENGTH. * * @return an integer containing the length of the * request body or -1 if the length is not known * */ public int getContentLength(); /** * Returns the MIME type of the body of the request, or * null if the type is not known. For HTTP servlets, * same as the value of the CGI variable CONTENT_TYPE. * * @return a String containing the name * of the MIME type of * the request, or null if the type is not known * */ public String getContentType(); /** * Retrieves the body of the request as binary data using * a {@link ServletInputStream}. Either this method or * {@link #getReader} may be called to read the body, not both. * * @return a {@link ServletInputStream} object containing * the body of the request * * @exception IllegalStateException if the {@link #getReader} method * has already been called for this request * * @exception IOException if an input or output exception occurred * */ public ServletInputStream getInputStream() throws IOException; /** * Returns the value of a request parameter as a String, * or null if the parameter does not exist. Request parameters * are extra information sent with the request. For HTTP servlets, * parameters are contained in the query string or posted form data. * *

You should only use this method when you are sure the * parameter has only one value. If the parameter might have * more than one value, use {@link #getParameterValues}. * *

If you use this method with a multivalued * parameter, the value returned is equal to the first value * in the array returned by getParameterValues. * *

If the parameter data was sent in the request body, such as occurs * with an HTTP POST request, then reading the body directly via {@link * #getInputStream} or {@link #getReader} can interfere * with the execution of this method. * * @param name a String specifying the * name of the parameter * * @return a String representing the * single value of the parameter * * @see #getParameterValues * */ public String getParameter(String name); /** * * Returns an Enumeration of String * objects containing the names of the parameters contained * in this request. If the request has * no parameters, the method returns an * empty Enumeration. * * @return an Enumeration of String * objects, each String containing * the name of a request parameter; or an * empty Enumeration if the * request has no parameters * */ public Enumeration getParameterNames(); /** * Returns an array of String objects containing * all of the values the given request parameter has, or * null if the parameter does not exist. * *

If the parameter has a single value, the array has a length * of 1. * * @param name a String containing the name of * the parameter whose value is requested * * @return an array of String objects * containing the parameter's values * * @see #getParameter * */ public String[] getParameterValues(String name); /** Returns a java.util.Map of the parameters of this request. * Request parameters * are extra information sent with the request. For HTTP servlets, * parameters are contained in the query string or posted form data. * * @return an immutable java.util.Map containing parameter names as * keys and parameter values as map values. The keys in the parameter * map are of type String. The values in the parameter map are of type * String array. * */ public Map getParameterMap(); /** * Returns the name and version of the protocol the request uses * in the form protocol/majorVersion.minorVersion, for * example, HTTP/1.1. For HTTP servlets, the value * returned is the same as the value of the CGI variable * SERVER_PROTOCOL. * * @return a String containing the protocol * name and version number * */ public String getProtocol(); /** * Returns the name of the scheme used to make this request, * for example, * http, https, or ftp. * Different schemes have different rules for constructing URLs, * as noted in RFC 1738. * * @return a String containing the name * of the scheme used to make this request * */ public String getScheme(); /** * Returns the host name of the server to which the request was sent. * It is the value of the part before ":" in the Host * header value, if any, or the resolved server name, or the server IP address. * * @return a String containing the name * of the server */ public String getServerName(); /** * Returns the port number to which the request was sent. * It is the value of the part after ":" in the Host * header value, if any, or the server port where the client connection * was accepted on. * * @return an integer specifying the port number * */ public int getServerPort(); /** * Retrieves the body of the request as character data using * a BufferedReader. The reader translates the character * data according to the character encoding used on the body. * Either this method or {@link #getInputStream} may be called to read the * body, not both. * * * @return a BufferedReader * containing the body of the request * * @exception UnsupportedEncodingException if the character set encoding * used is not supported and the * text cannot be decoded * * @exception IllegalStateException if {@link #getInputStream} method * has been called on this request * * @exception IOException if an input or output exception occurred * * @see #getInputStream * */ public BufferedReader getReader() throws IOException; /** * Returns the Internet Protocol (IP) address of the client * or last proxy that sent the request. * For HTTP servlets, same as the value of the * CGI variable REMOTE_ADDR. * * @return a String containing the * IP address of the client that sent the request * */ public String getRemoteAddr(); /** * Returns the fully qualified name of the client * or the last proxy that sent the request. * If the engine cannot or chooses not to resolve the hostname * (to improve performance), this method returns the dotted-string form of * the IP address. For HTTP servlets, same as the value of the CGI variable * REMOTE_HOST. * * @return a String containing the fully * qualified name of the client * */ public String getRemoteHost(); /** * * Stores an attribute in this request. * Attributes are reset between requests. This method is most * often used in conjunction with {@link RequestDispatcher}. * *

Attribute names should follow the same conventions as * package names. Names beginning with java.*, * javax.*, and com.sun.*, are * reserved for use by Sun Microsystems. *
If the object passed in is null, the effect is the same as * calling {@link #removeAttribute}. *
It is warned that when the request is dispatched from the * servlet resides in a different web application by * RequestDispatcher, the object set by this method * may not be correctly retrieved in the caller servlet. * * * @param name a String specifying * the name of the attribute * * @param o the Object to be stored * */ public void setAttribute(String name, Object o); /** * * Removes an attribute from this request. This method is not * generally needed as attributes only persist as long as the request * is being handled. * *

Attribute names should follow the same conventions as * package names. Names beginning with java.*, * javax.*, and com.sun.*, are * reserved for use by Sun Microsystems. * * * @param name a String specifying * the name of the attribute to remove * */ public void removeAttribute(String name); /** * * Returns the preferred Locale that the client will * accept content in, based on the Accept-Language header. * If the client request doesn't provide an Accept-Language header, * this method returns the default locale for the server. * * * @return the preferred Locale for the client * */ public Locale getLocale(); /** * * Returns an Enumeration of Locale objects * indicating, in decreasing order starting with the preferred locale, the * locales that are acceptable to the client based on the Accept-Language * header. * If the client request doesn't provide an Accept-Language header, * this method returns an Enumeration containing one * Locale, the default locale for the server. * * * @return an Enumeration of preferred * Locale objects for the client * */ public Enumeration getLocales(); /** * * Returns a boolean indicating whether this request was made using a * secure channel, such as HTTPS. * * * @return a boolean indicating if the request was made using a * secure channel * */ public boolean isSecure(); /** * * Returns a {@link RequestDispatcher} object that acts as a wrapper for * the resource located at the given path. * A RequestDispatcher object can be used to forward * a request to the resource or to include the resource in a response. * The resource can be dynamic or static. * *

The pathname specified may be relative, although it cannot extend * outside the current servlet context. If the path begins with * a "/" it is interpreted as relative to the current context root. * This method returns null if the servlet container * cannot return a RequestDispatcher. * *

The difference between this method and {@link * ServletContext#getRequestDispatcher} is that this method can take a * relative path. * * @param path a String specifying the pathname * to the resource. If it is relative, it must be * relative against the current servlet. * * @return a RequestDispatcher object * that acts as a wrapper for the resource * at the specified path, or null * if the servlet container cannot return a * RequestDispatcher * * @see RequestDispatcher * @see ServletContext#getRequestDispatcher * */ public RequestDispatcher getRequestDispatcher(String path); /** * * @deprecated As of Version 2.1 of the Java Servlet API, * use {@link ServletContext#getRealPath} instead. * */ public String getRealPath(String path); /** * Returns the Internet Protocol (IP) source port of the client * or last proxy that sent the request. * * @return an integer specifying the port number * * @since 2.4 */ public int getRemotePort(); /** * Returns the host name of the Internet Protocol (IP) interface on * which the request was received. * * @return a String containing the host * name of the IP on which the request was received. * * @since 2.4 */ public String getLocalName(); /** * Returns the Internet Protocol (IP) address of the interface on * which the request was received. * * @return a String containing the * IP address on which the request was received. * * @since 2.4 * */ public String getLocalAddr(); /** * Returns the Internet Protocol (IP) port number of the interface * on which the request was received. * * @return an integer specifying the port number * * @since 2.4 */ public int getLocalPort(); }





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