Class JXPathServletContexts
PageContext
, ServletRequest
, HttpSession
and ServletContext
.
The JXPathContext
returned by getPageContext()
provides access to all scopes via the PageContext.findAttribute() method.
Thus, an expression like "foo" will first look for the attribute named "foo" in the "page" context, then the "request" context, then the "session" one and
finally in the "application" context.
If you need to limit the attibute lookup to just one scope, you can use the pre-definded variables "page", "request", "session" and "application". For example, the expression "$session/foo" extracts the value of the session attribute named "foo".
Following are some implementation details. There is a separate JXPathContext for each of the four scopes. These contexts are chained according to the nesting of the scopes. So, the parent of the "page" JXPathContext is a "request" JXPathContext, whose parent is a "session" JXPathContext (that is if there is a session), whose parent is an "application" context.
The XPath context node for each context is the corresponding object: PageContext, ServletRequest, HttpSession or ServletContext. This feature can be used by servlets. A servlet can use one of the methods declared by this class and work with a specific JXPathContext for any scope.
Since JXPath chains lookups for variables and extension functions, variables and extension function declared in the outer scopes are also available in the inner scopes.
Each of the four context declares exactly one variable, the value of which is the corresponding object: PageContext, etc.
The "session" variable will be undefined if there is no session for this servlet. JXPath does not automatically create sessions.
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Constructor Summary
ConstructorsConstructorDescriptionDeprecated.Will be private in the next major version. -
Method Summary
Modifier and TypeMethodDescriptionstatic JXPathContext
getApplicationContext
(ServletContext servletContext) Returns a JXPathContext bound to the "application" scope.static JXPathContext
getPageContext
(PageContext pageContext) Returns a JXPathContext bound to the "page" scope.static JXPathContext
getRequestContext
(ServletRequest request, ServletContext servletContext) Returns a JXPathContext bound to the "request" scope.static JXPathContext
getSessionContext
(HttpSession session, ServletContext servletContext) Returns a JXPathContext bound to the "session" scope.
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Constructor Details
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JXPathServletContexts
Deprecated.Will be private in the next major version.Constructs a new instance.
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Method Details
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getApplicationContext
Returns a JXPathContext bound to the "application" scope. Caches that context within the servlet context itself.- Parameters:
servletContext
- operative- Returns:
- JXPathContext
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getPageContext
Returns a JXPathContext bound to the "page" scope. Caches that context within the PageContext itself.- Parameters:
pageContext
- as described- Returns:
- JXPathContext
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getRequestContext
public static JXPathContext getRequestContext(ServletRequest request, ServletContext servletContext) Returns a JXPathContext bound to the "request" scope. Caches that context within the request itself.- Parameters:
request
- as describedservletContext
- operative- Returns:
- JXPathContext
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getSessionContext
Returns a JXPathContext bound to the "session" scope. Caches that context within the session itself.- Parameters:
session
- as describedservletContext
- operative- Returns:
- JXPathContext
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