servlet::ServletContext Class Reference

#include <ServletContext.h>

Inheritance diagram for servlet::ServletContext:


Public Member Functions
virtual	~ServletContext ()
virtual ServletContext *	getContext (const std::string &uripath)=0
virtual int	getMajorVersion ()=0
virtual int	getMinorVersion ()=0
virtual std::string	getMimeType (const std::string &file)=0
virtual std::auto_ptr < std::set< std::string > >	getResourcePaths (const std::string &path)=0
virtual std::string	getResource (const std::string &path)=0
virtual std::istream &	getResourceAsStream (const std::string &path)=0
virtual RequestDispatcher *	getRequestDispatcher (const std::string &path)=0
virtual RequestDispatcher *	getNamedDispatcher (const std::string &name)=0
virtual void	log (const std::string &msg) const =0
virtual void	log (const std::string &message, const std::exception &e) const =0
virtual std::string	getRealPath (const std::string &path)=0
virtual std::string	getServerInfo ()=0
virtual std::string	getInitParameter (const std::string &name)=0
virtual std::auto_ptr < std::vector< std::string > >	getInitParameterNames ()=0
virtual boost::shared_ptr< void >	getAttribute (const std::string &name)=0
template<typename T >
T	getAttribute (const std::string &name)
virtual std::auto_ptr < std::vector< std::string > >	getAttributeNames ()=0
virtual void	setAttribute (const std::string &name, boost::shared_ptr< void > object)=0
template<typename T >
void	setAttribute (const std::string &name, boost::shared_ptr< T > object)
template<typename T >
void	setAttribute (const std::string &name, const T &object)
virtual void	removeAttribute (const std::string &name)=0
virtual bool	hasAttribute (const std::string &name) const =0
virtual std::string	getServletContextName () const =0

Detailed Description

ServletContext

Defines a set of methods that a servlet uses to communicate with its servlet container, for example, to get the MIME type of a file, dispatch requests, or write to a log file.

There is one context per "web application" per Java Virtual Machine. (A "web application" is a collection of servlets and content installed under a specific subset of the server's URL namespace such as /catalog and possibly installed via a .war file.)

In the case of a web application marked "distributed" in its deployment descriptor, there will be one context instance for each virtual machine. In this situation, the context cannot be used as a location to share global information (because the information won't be truly global). Use an external resource like a database instead.

The ServletContext object is contained within the servlet::ServletConfig object, which the Web server provides the servlet when the servlet is initialized.

Author:: Various

Version:: $Version$

See also:: Servlet::getServletConfig
ServletConfig::getServletContext

Definition at line 96 of file ServletContext.h.

Constructor & Destructor Documentation

virtual servlet::ServletContext::~ServletContext ( ) [inline, virtual]

Definition at line 98 of file ServletContext.h.

Member Function Documentation

template<typename T >

T servlet::ServletContext::getAttribute ( const std::string & name ) [inline]

Reimplemented in container::serverconfig::AppContext.

T servlet::ServletContext::getAttribute ( const std::string & name ) [inline, pure virtual]

Returns the servlet container attribute with the given name, or null if there is no attribute by that name. An attribute allows a servlet container to give the servlet additional information not already provided by this interface. See your server documentation for information about its attributes. A list of supported attributes can be retrieved using getAttributeNames.

The attribute is returned as a java.lang.Object or some subclass. Attribute names should follow the same convention as package names. The Java Servlet API specification reserves names matching java.*, javax.*, and sun.*.

Parameters:

name a String specifying the name of the attribute

Returns:: an Object containing the value of the attribute, or null if no attribute exists matching the given name

See also:: ServletContext::getAttributeNames

Implemented in container::serverconfig::AppContext.

Definition at line 595 of file ServletContext.h.

virtual std::auto_ptr< std::vector<std::string> > servlet::ServletContext::getAttributeNames ( ) [pure virtual]

Returns an Enumeration containing the attribute names available within this servlet context. Use the getAttribute method with an attribute name to get the value of an attribute.

Returns:: an Enumeration of attribute names

See also:: getAttribute

Implemented in container::serverconfig::AppContext.

virtual ServletContext* servlet::ServletContext::getContext ( const std::string & uripath ) [pure virtual]

Returns a ServletContext object that corresponds to a specified URL on the server.

This method allows servlets to gain access to the context for various parts of the server, and as needed obtain servlet::RequestDispatcher objects from the context. The given path must be begin with "/", is interpreted relative to the server's document root and is matched against the context roots of other web applications hosted on this container.

In a security conscious environment, the servlet container may return null for a given URL.

Parameters:

uripath a String specifying the context path of another web application in the container.

Returns:: the ServletContext object that corresponds to the named URL, or null if either none exists or the container wishes to restrict this access.

See also:: RequestDispatcher

Implemented in container::serverconfig::AppContext.

virtual std::string servlet::ServletContext::getInitParameter ( const std::string & name ) [pure virtual]

Returns a String containing the value of the named context-wide initialization parameter, or null if the parameter does not exist.

This method can make available configuration information useful to an entire "web application". For example, it can provide a webmaster's email address or the name of a system that holds critical data.

Parameters:

name a String containing the name of the parameter whose value is requested

Returns:: a String containing at least the servlet container name and version number

See also:: ServletConfig::getInitParameter

Implemented in container::serverconfig::AppContext.

virtual std::auto_ptr< std::vector<std::string> > servlet::ServletContext::getInitParameterNames ( ) [pure virtual]

Returns the names of the context's initialization parameters as an Enumeration of String objects, or an empty Enumeration if the context has no initialization parameters.

Returns:: an Enumeration of String objects containing the names of the context's initialization parameters

See also:: ServletConfig::getInitParameter

Implemented in container::serverconfig::AppContext.

virtual int servlet::ServletContext::getMajorVersion ( ) [pure virtual]

Returns the major version of the Java Servlet API that this servlet container supports. All implementations that comply with Version 2.4 must have this method return the integer 2.

Returns:: 2

Implemented in container::serverconfig::AppContext.

virtual std::string servlet::ServletContext::getMimeType ( const std::string & file ) [pure virtual]

Returns the MIME type of the specified file, or null if the MIME type is not known. The MIME type is determined by the configuration of the servlet container, and may be specified in a web application deployment descriptor. Common MIME types are "text/html" and "image/gif".

Parameters:

file a String specifying the name of a file

Returns:: a String specifying the file's MIME type

Implemented in container::serverconfig::AppContext.

virtual int servlet::ServletContext::getMinorVersion ( ) [pure virtual]

Returns the minor version of the Servlet API that this servlet container supports. All implementations that comply with Version 2.4 must have this method return the integer 4.

Returns:: 4

Implemented in container::serverconfig::AppContext.

virtual RequestDispatcher* servlet::ServletContext::getNamedDispatcher ( const std::string & name ) [pure virtual]

Returns a servlet::RequestDispatcher object that acts as a wrapper for the named servlet.

Servlets (and JSP pages also) may be given names via server administration or via a web application deployment descriptor. A servlet instance can determine its name using servlet::ServletConfig#getServletName.

This method returns null if the ServletContext cannot return a RequestDispatcher for any reason.

Parameters:

name a String specifying the name of a servlet to wrap

Returns:: a RequestDispatcher object that acts as a wrapper for the named servlet, or null if the ServletContext cannot return a RequestDispatcher

See also:

RequestDispatcher

ServletContext::getContext

ServletConfig::getServletName

Implemented in container::serverconfig::AppContext.

virtual std::string servlet::ServletContext::getRealPath ( const std::string & path ) [pure virtual]

Returns a String containing the real path for a given virtual path. For example, the path "/index.html" returns the absolute file path on the server's filesystem would be served by a request for "http://host/contextPath/index.html", where contextPath is the context path of this ServletContext..

The real path returned will be in a form appropriate to the computer and operating system on which the servlet container is running, including the proper path separators. This method returns null if the servlet container cannot translate the virtual path to a real path for any reason (such as when the content is being made available from a .war archive).

Parameters:

path a String specifying a virtual path

Returns:: a String specifying the real path, or null if the translation cannot be performed

Implemented in container::serverconfig::AppContext.

virtual RequestDispatcher* servlet::ServletContext::getRequestDispatcher ( const std::string & path ) [pure virtual]

Returns a servlet::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 must begin with a "/" and is interpreted as relative to the current context root. Use getContext to obtain a RequestDispatcher for resources in foreign contexts. This method returns null if the ServletContext cannot return a RequestDispatcher.

Parameters:

path a String specifying the pathname to the resource

Returns:: a RequestDispatcher object that acts as a wrapper for the resource at the specified path, or null if the ServletContext cannot return a RequestDispatcher

See also:: servlet::RequestDispatcher
servlet::ServletContext::getContext

Implemented in container::serverconfig::AppContext.

virtual std::string servlet::ServletContext::getResource ( const std::string & path ) [pure virtual]

Returns a URL to the resource that is mapped to a specified path. The path must begin with a "/" and is interpreted as relative to the current context root.

This method allows the servlet container to make a resource available to servlets from any source. Resources can be located on a local or remote file system, in a database, or in a .war file.

The servlet container must implement the URL handlers and URLConnection objects that are necessary to access the resource.

This method returns null if no resource is mapped to the pathname.

Some containers may allow writing to the URL returned by this method using the methods of the URL class.

The resource content is returned directly, so be aware that requesting a .jsp page returns the JSP source code. Use a RequestDispatcher instead to include results of an execution.

This method has a different purpose than java.lang.Class.getResource, which looks up resources based on a class loader. This method does not use class loaders.

Parameters:

path a String specifying the path to the resource

Returns:: the resource located at the named path, or null if there is no resource at that path

Exceptions:

MalformedURLException

if the pathname is not given in the correct form

Implemented in container::serverconfig::AppContext.

virtual std::istream& servlet::ServletContext::getResourceAsStream ( const std::string & path ) [pure virtual]

Returns the resource located at the named path as an InputStream object.

The data in the InputStream can be of any type or length. The path must be specified according to the rules given in getResource. This method returns null if no resource exists at the specified path.

Meta-information such as content length and content type that is available via getResource method is lost when using this method.

The servlet container must implement the URL handlers and URLConnection objects necessary to access the resource.

This method is different from java.lang.Class.getResourceAsStream, which uses a class loader. This method allows servlet containers to make a resource available to a servlet from any location, without using a class loader.

Parameters:

path a String specifying the path to the resource

Returns:: the InputStream returned to the servlet, or null if no resource exists at the specified path

Implemented in container::serverconfig::AppContext.

virtual std::auto_ptr< std::set<std::string> > servlet::ServletContext::getResourcePaths ( const std::string & path ) [pure virtual]

Returns a directory-like listing of all the paths to resources within the web application whose longest sub-path matches the supplied path argument. Paths indicating subdirectory paths end with a '/'. The returned paths are all relative to the root of the web application and have a leading '/'. For example, for a web application containing<br>

/welcome.html
/catalog/index.html
/catalog/products.html
/catalog/offers/books.html
/catalog/offers/music.html
/customer/login.jsp
/WEB-INF/web.xml
/WEB-INF/classes/com.acme.OrderServlet.class,

getResourcePaths("/") returns {"/welcome.html", "/catalog/", "/customer/", "/WEB-INF/"}
getResourcePaths("/catalog/") returns {"/catalog/index.html", "/catalog/products.html", "/catalog/offers/"}.

Parameters:

path

the partial path used to match the resources, which must start with a /

Returns:: a Set containing the directory listing, or null if there are no resources in the web application whose path begins with the supplied path.

Since:: Servlet 2.3

Implemented in container::serverconfig::AppContext.

virtual std::string servlet::ServletContext::getServerInfo ( ) [pure virtual]

Returns the name and version of the servlet container on which the servlet is running.

The form of the returned string is servername/versionnumber. For example, the JavaServer Web Development Kit may return the string JavaServer Web Dev Kit/1.0.

The servlet container may return other optional information after the primary string in parentheses, for example, JavaServer Web Dev Kit/1.0 (JDK 1.1.6; Windows NT 4.0 x86).

Returns:: a String containing at least the servlet container name and version number

Implemented in container::serverconfig::AppContext.

virtual std::string servlet::ServletContext::getServletContextName ( ) const [pure virtual]

Returns the name of this web application corresponding to this ServletContext as specified in the deployment descriptor for this web application by the display-name element.

Returns:: The name of the web application or null if no name has been declared in the deployment descriptor.

Since:: Servlet 2.3

Implemented in container::serverconfig::AppContext.

virtual bool servlet::ServletContext::hasAttribute ( const std::string & name ) const [pure virtual]

[C++ Servlet API Extention]

Returns the false if no attribute of the given name exists. Returns true otherwize

Parameters:

name a String specifying the name of the attribute

Returns:: false if the attribute does not exist. true otherwize

Implemented in container::serverconfig::AppContext.

virtual void servlet::ServletContext::log	(	const std::string &	message,
		const std::exception &	e
	)			const `[pure virtual]`

Writes an explanatory message and a stack trace for a given Throwable exception to the servlet log file. The name and type of the servlet log file is specific to the servlet container, usually an event log.

Parameters:

	message	a `std::string` that describes the error or exception
	e	the `std::exception` error or exception

Implemented in container::serverconfig::AppContext.

virtual void servlet::ServletContext::log ( const std::string & msg ) const [pure virtual]

Writes the specified message to a servlet log file, usually an event log. The name and type of the servlet log file is specific to the servlet container.

Parameters:

msg a String specifying the message to be written to the log file

Implemented in container::serverconfig::AppContext.

virtual void servlet::ServletContext::removeAttribute ( const std::string & name ) [pure virtual]

Removes the attribute with the given name from the servlet context. After removal, subsequent calls to getAttribute to retrieve the attribute's value will return null.

If listeners are configured on the ServletContext the container notifies them accordingly.

Parameters:

name a String specifying the name of the attribute to be removed

Implemented in container::serverconfig::AppContext.

template<typename T >

void servlet::ServletContext::setAttribute	(	const std::string &	name,
		const T &	object
	)			`[inline]`

Definition at line 602 of file ServletContext.h.

References setAttribute().

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template<typename T >

void servlet::ServletContext::setAttribute	(	const std::string &	name,
		boost::shared_ptr< T >	object
	)			`[inline]`

Definition at line 543 of file ServletContext.h.

References setAttribute().

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virtual void servlet::ServletContext::setAttribute	(	const std::string &	name,
		boost::shared_ptr< void >	object
	)			`[pure virtual]`

Binds an object to a given attribute name in this servlet context. If the name specified is already used for an attribute, this method will replace the attribute with the new to the new attribute.

If listeners are configured on the ServletContext the container notifies them accordingly.

If a null value is passed, the effect is the same as calling removeAttribute().

Attribute names should follow the same convention as package names. The Java Servlet API specification reserves names matching java.*, javax.*, and sun.*.

Parameters:

	name	a `String` specifying the name of the attribute
	object	an `Object` representing the attribute to be bound

Implemented in container::serverconfig::AppContext.

Referenced by setAttribute().

The documentation for this class was generated from the following file:

include/servlet/ServletContext.h

CPPSERV

servlet::ServletContext Class Reference

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation