ServletContextWrapper (Oracle® Coherence Java API Reference)

java.lang.Object
- com.tangosol.coherence.servlet.api23.ServletContextWrapper

All Implemented Interfaces:

javax.servlet.ServletContext
```
public class ServletContextWrapper
extends Object
implements javax.servlet.ServletContext
```
An implementation of the ServletContext interface that provides for clustered storage for ServletContext attributes using a fully replicated cache service.

Version:

Coherence 2.3

Author:

cp 2003.07.21

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`class`	`ServletContextWrapper.ServletContextMapListener` Inner class: A listener to listen to the clustered servlet context attributes and make those same changes to the local ServletContext.

Constructor Summary

Constructors
Constructor and Description
`ServletContextWrapper(SessionHelper helper, javax.servlet.ServletContext ctx)` Construct a Coherence ServletContext that will optionally provide clustered storage for ServletContext attributes.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`protected void`	`ensureCluster()` Ensure that the cluster setup for context attributes is done.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`Object`	`getAttribute(String sName)` Returns the servlet container attribute with the given name, or null if there is no attribute by that name.
`protected NamedCache`	`getAttributeMap()` Get the clustered attribute map.
`Enumeration`	`getAttributeNames()` Returns an Enumeration containing the attribute names available within this servlet context.
`javax.servlet.ServletContext`	`getContext(String sUriPath)` Returns a ServletContext object that corresponds to a specified URL on the server.
`String`	`getContextPath()` Returns the context path of the web application, if available.
`protected String`	`getDescription()` Returns a string representation of this object's attributes.
`String`	`getInitParameter(String sName)` Returns a String containing the value of the named context-wide initialization parameter, or null if the parameter does not exist.
`Enumeration`	`getInitParameterNames()` 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.
`int`	`getMajorVersion()` Returns the major version of the Java Servlet API that this servlet container supports.
`String`	`getMimeType(String sFile)` Returns the MIME type of the specified file, or null if the MIME type is not known.
`int`	`getMinorVersion()` Returns the minor version of the Servlet API that this servlet container supports.
`javax.servlet.RequestDispatcher`	`getNamedDispatcher(String sName)` Returns a RequestDispatcher object that acts as a wrapper for the named servlet.
`String`	`getRealPath(String sPath)` Returns a String containing the real path for a given virtual path.
`javax.servlet.RequestDispatcher`	`getRequestDispatcher(String sPath)` Returns a RequestDispatcher object that acts as a wrapper for the resource located at the given path.
`URL`	`getResource(String sPath)` Returns a URL to the resource that is mapped to a specified path.
`InputStream`	`getResourceAsStream(String sPath)` Returns the resource located at the named path as an InputStream object.
`Set`	`getResourcePaths(String sPath)` Returns a directory-like listing of all the paths to resources within the web application whose longest sub-path matches the supplied path argument.
`String`	`getServerInfo()` Returns the name and version of the servlet container on which the servlet is running.
`javax.servlet.Servlet`	`getServlet(String sName)` Deprecated. As of Java Servlet API 2.1, with no direct replacement.
`protected javax.servlet.ServletContext`	`getServletContext()` Get the application server's ServletContext.
`String`	`getServletContextName()` Returns the name of this web application correponding to this ServletContext as specified in the deployment descriptor for this web application by the display-name element.
`Enumeration`	`getServletNames()` Deprecated. As of Java Servlet API 2.1, with no replacement.
`Enumeration`	`getServlets()` Deprecated. As of Java Servlet API 2.0, with no replacement.
`protected SessionHelper`	`getSessionHelper()` Get the SessionHelper for this ServletContext wrapper.
`int`	`hashCode()` Returns a hash code value for the object.
`protected MapListener`	`instantiateServletContextMapListener()` Factory method: Instantiate a listener to listen to the clustered servlet context attributes and make those same changes to the local ServletContext.
`protected boolean`	`isClustered()` Determine if the context clusters attributes.
`void`	`log(Exception e, String sMsg)` Deprecated. As of Java Servlet API 2.1, use `log(String, Throwable)` instead.
`void`	`log(String sMsg)` Writes the specified message to a servlet log file, usually an event log.
`void`	`log(String sMsg, Throwable e)` Writes an explanatory message and a stack trace for a given Throwable exception to the servlet log file.
`void`	`removeAttribute(String sName)` Removes the attribute with the given name from the servlet context.
`void`	`setAttribute(String sName, Object oValue)` Binds an object to a given attribute name in this servlet context.
`String`	`toString()` Returns a string representation of the object.

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - ServletContextWrapper
```
public ServletContextWrapper(SessionHelper helper,
                             javax.servlet.ServletContext ctx)
```
    Construct a Coherence ServletContext that will optionally provide clustered storage for ServletContext attributes.
    
    Parameters:
    
    helper - the application's session helper
    
    ctx - the application server's ServletContext object
- Method Detail
  - getAttribute
```
public Object getAttribute(String sName)
```
    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.
    
    Specified by:
    
    getAttribute in interface javax.servlet.ServletContext
    
    Parameters:
    
    sName - 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
  - getAttributeNames
```
public Enumeration getAttributeNames()
```
    Returns an Enumeration containing the attribute names available within this servlet context. Use the getAttribute(String) method with an attribute name to get the value of an attribute.
    
    Specified by:
    
    getAttributeNames in interface javax.servlet.ServletContext
    
    Returns:
    
    an Enumeration of attribute names
  - getContext
```
public javax.servlet.ServletContext getContext(String sUriPath)
```
    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 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.
    
    Specified by:
    
    getContext in interface javax.servlet.ServletContext
    
    Parameters:
    
    sUriPath - 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
  - getInitParameter
```
public String getInitParameter(String sName)
```
    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.
    
    Specified by:
    
    getInitParameter in interface javax.servlet.ServletContext
    
    Parameters:
    
    sName - 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
  - getInitParameterNames
```
public Enumeration getInitParameterNames()
```
    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.
    
    Specified by:
    
    getInitParameterNames in interface javax.servlet.ServletContext
    
    Returns:
    
    an Enumeration of String objects containing the names of the context's initialization parameters
  - getMajorVersion
```
public int getMajorVersion()
```
    Returns the major version of the Java Servlet API that this servlet container supports.
    
    Specified by:
    
    getMajorVersion in interface javax.servlet.ServletContext
    
    Returns:
    
    the major version of the Java Servlet API that this servlet container supports
  - getMimeType
```
public String getMimeType(String sFile)
```
    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".
    
    Specified by:
    
    getMimeType in interface javax.servlet.ServletContext
    
    Parameters:
    
    sFile - a String specifying the name of a file
    
    Returns:
    
    a String specifying the file's MIME type
  - getMinorVersion
```
public int getMinorVersion()
```
    Returns the minor version of the Servlet API that this servlet container supports.
    
    Specified by:
    
    getMinorVersion in interface javax.servlet.ServletContext
    
    Returns:
    
    the minor version of the Servlet API that this servlet container supports
  - getNamedDispatcher
```
public javax.servlet.RequestDispatcher getNamedDispatcher(String sName)
```
    Returns a 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 ServletConfig.getServletName().
    This method returns null if the ServletContext cannot return a RequestDispatcher for any reason.
    
    Specified by:
    
    getNamedDispatcher in interface javax.servlet.ServletContext
    
    Parameters:
    
    sName - a String specifying the name of a servlet to wrap
    
    Returns:
    
    a RequestDispatcher object that acts as a wrapper for the named servlet
  - getRealPath
```
public String getRealPath(String sPath)
```
    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).
    
    Specified by:
    
    getRealPath in interface javax.servlet.ServletContext
    
    Parameters:
    
    sPath - a String specifying a virtual path
    
    Returns:
    
    a String specifying the real path, or null if the translation cannot be performed
  - getRequestDispatcher
```
public javax.servlet.RequestDispatcher getRequestDispatcher(String sPath)
```
    Returns a 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.
    
    Specified by:
    
    getRequestDispatcher in interface javax.servlet.ServletContext
    
    Parameters:
    
    sPath - a String specifying the pathname to the resource
    
    Returns:
    
    a RequestDispatcher object that acts as a wrapper for the resource at the specified path
  - getResource
```
public URL getResource(String sPath)
                throws MalformedURLException
```
    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 Class.getResource, which looks up resources based on a class loader. This method does not use class loaders.
    
    Specified by:
    
    getResource in interface javax.servlet.ServletContext
    
    Parameters:
    
    sPath - 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
    
    Throws:
    
    MalformedURLException - if the pathname is not given in the correct form
  - getResourceAsStream
```
public InputStream getResourceAsStream(String sPath)
```
    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 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.
    
    Specified by:
    
    getResourceAsStream in interface javax.servlet.ServletContext
    
    Parameters:
    
    sPath - 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
  - getResourcePaths
```
public Set getResourcePaths(String sPath)
```
    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 '/'.
    
    Specified by:
    
    getResourcePaths in interface javax.servlet.ServletContext
    
    Parameters:
    
    sPath - 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.
  - getServerInfo
```
public String getServerInfo()
```
    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).
    
    Specified by:
    
    getServerInfo in interface javax.servlet.ServletContext
    
    Returns:
    
    a String containing at least the servlet container name and version number
  - getServlet
```
public javax.servlet.Servlet getServlet(String sName)
                                 throws javax.servlet.ServletException
```
    Deprecated. As of Java Servlet API 2.1, with no direct replacement.
    
    This method was originally defined to retrieve a servlet from a ServletContext. In this version, this method always returns null and remains only to preserve binary compatibility. This method will be permanently removed in a future version of the Java Servlet API.
    In lieu of this method, servlets can share information using the ServletContext class and can perform shared business logic by invoking methods on common non-servlet classes.
    
    Specified by:
    
    getServlet in interface javax.servlet.ServletContext
    
    Parameters:
    
    sName - a servlet name
    
    Throws:
    
    javax.servlet.ServletException
  - getServletContextName
```
public String getServletContextName()
```
    Returns the name of this web application correponding to this ServletContext as specified in the deployment descriptor for this web application by the display-name element.
    
    Specified by:
    
    getServletContextName in interface javax.servlet.ServletContext
    
    Returns:
    
    the name of the web application or null if no name has been declared in the deployment descriptor.
  - getServletNames
```
public Enumeration getServletNames()
```
    Deprecated. As of Java Servlet API 2.1, with no replacement.
    
    This method was originally defined to return an Enumeration of all the servlet names known to this context. In this version, this method always returns an empty Enumeration and remains only to preserve binary compatibility. This method will be permanently removed in a future version of the Java Servlet API.
    
    Specified by:
    
    getServletNames in interface javax.servlet.ServletContext
  - getServlets
```
public Enumeration getServlets()
```
    Deprecated. As of Java Servlet API 2.0, with no replacement.
    
    This method was originally defined to return an Enumeration of all the servlets known to this servlet context. In this version, this method always returns an empty enumeration and remains only to preserve binary compatibility. This method will be permanently removed in a future version of the Java Servlet API.
    
    Specified by:
    
    getServlets in interface javax.servlet.ServletContext
  - log
```
public void log(String sMsg)
```
    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.
    
    Specified by:
    
    log in interface javax.servlet.ServletContext
    
    Parameters:
    
    sMsg - a String specifying the message to be written to the log file
  - log
```
public void log(Exception e,
                String sMsg)
```
    Deprecated. As of Java Servlet API 2.1, use log(String, Throwable) instead.
    
    This method was originally defined to write an exception's stack trace and an explanatory error message to the servlet log file.
    
    Specified by:
    
    log in interface javax.servlet.ServletContext
    
    Parameters:
    
    e - an exception to log
    
    sMsg - a message to log
  - log
```
public void log(String sMsg,
                Throwable e)
```
    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.
    
    Specified by:
    
    log in interface javax.servlet.ServletContext
    
    Parameters:
    
    sMsg - a String that describes the error or exception
    
    e - the Throwable error or exception
  - removeAttribute
```
public void removeAttribute(String sName)
```
    Removes the attribute with the given name from the servlet context. After removal, subsequent calls to getAttribute(String) to retrieve the attribute's value will return null.
    If listeners are configured on the ServletContext the container notifies them accordingly.
    
    Specified by:
    
    removeAttribute in interface javax.servlet.ServletContext
    
    Parameters:
    
    sName - a String specifying the name of the attribute to be removed
  - setAttribute
```
public void setAttribute(String sName,
                         Object oValue)
```
    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().
    
    Specified by:
    
    setAttribute in interface javax.servlet.ServletContext
    
    Parameters:
    
    sName - a String specifying the name of the attribute
    
    oValue - an Object representing the attribute to be bound
  - hashCode
```
public int hashCode()
```
    Returns a hash code value for the object.
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    
    a hash code value for this object
  - equals
```
public boolean equals(Object obj)
```
    Indicates whether some other object is "equal to" this one.
    
    Overrides:
    
    equals in class Object
    
    Parameters:
    
    obj - the reference object with which to compare
    
    Returns:
    
    true if this object is the same as the obj argument; false otherwise
  - toString
```
public String toString()
```
    Returns a string representation of the object.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    a string representation of the object
  - getContextPath
```
public String getContextPath()
```
    Returns the context path of the web application, if available.
    
    Specified by:
    
    getContextPath in interface javax.servlet.ServletContext
    
    Returns:
    
    the context path of the web application, if available; null otherwise
  - getDescription
```
protected String getDescription()
```
    Returns a string representation of this object's attributes.
    
    Returns:
    
    a string representation of this object's attributes
  - getSessionHelper
```
protected SessionHelper getSessionHelper()
```
    Get the SessionHelper for this ServletContext wrapper.
    
    Returns:
    
    the SessionHelper for this ServletContext wrapper
  - getServletContext
```
protected javax.servlet.ServletContext getServletContext()
```
    Get the application server's ServletContext.
    
    Returns:
    
    the the application server's ServletContext
  - isClustered
```
protected boolean isClustered()
```
    Determine if the context clusters attributes.
    
    Returns:
    
    true if the context clusters attributes; false otherwise
  - ensureCluster
```
protected void ensureCluster()
```
    Ensure that the cluster setup for context attributes is done. This has no effect if the context is not clustered or if the setup is already done.
  - getAttributeMap
```
protected NamedCache getAttributeMap()
```
    Get the clustered attribute map.
    
    Returns:
    
    the clustered attribute map, or null if the context does not cluster attributes
  - instantiateServletContextMapListener
```
protected MapListener instantiateServletContextMapListener()
```
    Factory method: Instantiate a listener to listen to the clustered servlet context attributes and make those same changes to the local ServletContext.
    
    Returns:
    
    a MapListener that delegates to the wrapped (local) ServletContext to propagate ServletContext attribute changes (possibly coming from different nodes)

Class ServletContextWrapper

Nested Class Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ServletContextWrapper

Method Detail

getAttribute

getAttributeNames

getContext

getInitParameter

getInitParameterNames

getMajorVersion

getMimeType

getMinorVersion

getNamedDispatcher

getRealPath

getRequestDispatcher

getResource

getResourceAsStream

getResourcePaths

getServerInfo

getServlet

getServletContextName

getServletNames

getServlets

log

log

log

removeAttribute

setAttribute

hashCode

equals

toString

getContextPath

getDescription

getSessionHelper

getServletContext

isClustered

ensureCluster

getAttributeMap

instantiateServletContextMapListener