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java.lang.Object javax.el.ELResolver javax.servlet.jsp.el.ImplicitObjectELResolver
public class ImplicitObjectELResolver
Defines variable resolution behavior for the EL implicit objects defined in the JSP specification.
The following variables are resolved by this ELResolver
,
as per the JSP specification:
pageContext
- the PageContext
object.pageScope
- a Map
that maps page-scoped
attribute names to their values.requestScope
- a Map
that maps
request-scoped attribute names to their values.sessionScope
- a Map
that maps
session-scoped attribute names to their values.applicationScope
- a Map
that maps
application-scoped attribute names to their values.param
- a Map
that maps parameter
names to a single String parameter value (obtained by calling
ServletRequest.getParameter(String name)).
paramValues
- a Map
that maps parameter
names to a String[]
of all values for that
parameter (obtained by calling
ServletRequest.getParameterValues(String name))
.header
- a Map
that maps header names
to a single String header value (obtained by calling
HttpServletRequest.getHeader(String name))
.headerValues
- a Map
that maps header
names to a String[]
of all values for that header
(obtained by calling
HttpServletRequest.getHeaders(String))
.cookie
- a Map
that maps cookie names
to a single Cookie
object. Cookies are retrieved
according to the semantics of
HttpServletRequest.getCookies()
. If the same name
is shared by multiple cookies, an implementation must use the
first one encountered in the array of Cookie
objects
returned by the getCookies()
method. However, users
of the cookie implicit object must be aware that the ordering
of cookies is currently unspecified in the servlet
specification.initParam
- a Map
that maps context
initialization parameter names to their String parameter
value (obtained by calling
ServletContext.getInitParameter(String name))
.
ELResolver
Field Summary |
---|
Fields inherited from class javax.el.ELResolver |
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RESOLVABLE_AT_DESIGN_TIME, TYPE |
Constructor Summary | |
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ImplicitObjectELResolver()
|
Method Summary | |
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Class<String> |
getCommonPropertyType(ELContext context,
Object base)
If the base object is null , returns
String.class . |
Iterator<FeatureDescriptor> |
getFeatureDescriptors(ELContext context,
Object base)
If the base object is null , and the property matches
the name of a JSP implicit object, returns an Iterator
containing FeatureDescriptor objects with information
about each JSP implicit object resolved by this resolver. |
Class |
getType(ELContext context,
Object base,
Object property)
If the base object is null , and the property matches
the name of a JSP implicit object, returns null to
indicate that no types are ever accepted to setValue() . |
Object |
getValue(ELContext context,
Object base,
Object property)
If the base object is null , and the property matches
the name of a JSP implicit object, returns the implicit object. |
boolean |
isReadOnly(ELContext context,
Object base,
Object property)
If the base object is null , and the property matches
the name of a JSP implicit object, returns true
to indicate that implicit objects cannot be overwritten. |
void |
setValue(ELContext context,
Object base,
Object property,
Object val)
If the base object is null , and the property matches
the name of a JSP implicit object, throws
PropertyNotWritableException to indicate that implicit
objects cannot be overwritten. |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public ImplicitObjectELResolver()
Method Detail |
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public Object getValue(ELContext context, Object base, Object property)
null
, and the property matches
the name of a JSP implicit object, returns the implicit object.
The propertyResolved
property of the
ELContext
object must be set to true
by
this resolver before returning if an implicit object is matched. If
this property is not true
after this method is called,
the caller should ignore the return value.
getValue
in class ELResolver
context
- The context of this evaluation.base
- Only null
is handled by this resolver.
Other values will result in an immediate return.property
- The name of the implicit object to resolve.
propertyResolved
property of
ELContext
was set to true
, then
the implicit object; otherwise undefined.
NullPointerException
- if context is null
ELException
- if an exception was thrown while performing
the property or variable resolution. The thrown exception
must be included as the cause property of this exception, if
available.public Class getType(ELContext context, Object base, Object property)
null
, and the property matches
the name of a JSP implicit object, returns null
to
indicate that no types are ever accepted to setValue()
.
The propertyResolved
property of the
ELContext
object must be set to true
by
this resolver before returning if an implicit object is matched. If
this property is not true
after this method is called,
the caller should ignore the return value.
getType
in class ELResolver
context
- The context of this evaluation.base
- Only null
is handled by this resolver.
Other values will result in an immediate return.property
- The name of the implicit object to resolve.
propertyResolved
property of
ELContext
was set to true
, then
null
; otherwise undefined.
NullPointerException
- if context is null
ELException
- if an exception was thrown while performing
the property or variable resolution. The thrown exception
must be included as the cause property of this exception, if
available.public void setValue(ELContext context, Object base, Object property, Object val)
null
, and the property matches
the name of a JSP implicit object, throws
PropertyNotWritableException
to indicate that implicit
objects cannot be overwritten.
The propertyResolved
property of the
ELContext
object must be set to true
by
this resolver before returning if an implicit object is matched. If
this property is not true
after this method is called,
the caller should ignore the return value.
setValue
in class ELResolver
context
- The context of this evaluation.base
- Only null
is handled by this resolver.
Other values will result in an immediate return.property
- The name of the implicit object.val
- The value to be associated with the implicit object.
NullPointerException
- if context is null
.
PropertyNotWritableException
- always thrown, if the
implicit object name is recognized by this resolver.
ELException
- if an exception was thrown while performing
the property or variable resolution. The thrown exception
must be included as the cause property of this exception, if
available.public boolean isReadOnly(ELContext context, Object base, Object property)
null
, and the property matches
the name of a JSP implicit object, returns true
to indicate that implicit objects cannot be overwritten.
The propertyResolved
property of the
ELContext
object must be set to true
by
this resolver before returning if an implicit object is matched. If
this property is not true
after this method is called,
the caller should ignore the return value.
isReadOnly
in class ELResolver
context
- The context of this evaluation.base
- Only null
is handled by this resolver.
Other values will result in an immediate return.property
- The name of the implicit object.
propertyResolved
property of
ELContext
was set to true
, then
true
; otherwise undefined.
NullPointerException
- if context is null
.
ELException
- if an exception was thrown while performing
the property or variable resolution. The thrown exception
must be included as the cause property of this exception, if
available.public Iterator<FeatureDescriptor> getFeatureDescriptors(ELContext context, Object base)
null
, and the property matches
the name of a JSP implicit object, returns an Iterator
containing FeatureDescriptor
objects with information
about each JSP implicit object resolved by this resolver. Otherwise,
returns null
.
The Iterator
returned must contain one instance of
FeatureDescriptor
for each of the EL implicit objects
defined by the JSP spec. Each info object contains information about
a single implicit object, and is initialized as follows:
false
false
true
FeatureDescriptor
s:
ELResolver.TYPE
- The runtime type of the implicit object.ELResolver.RESOLVABLE_AT_DESIGN_TIME
- true
.
getFeatureDescriptors
in class ELResolver
context
- The context of this evaluation.base
- Only null
is handled by this resolver.
Other values will result in a null
return value.
Iterator
containing one
FeatureDescriptor
object for each implicit object, or
null
if base
is not null
.FeatureDescriptor
public Class<String> getCommonPropertyType(ELContext context, Object base)
null
, returns
String.class
. Otherwise, returns null
.
getCommonPropertyType
in class ELResolver
context
- The context of this evaluation.base
- Only null
is handled by this resolver.
Other values will result in a null
return value.
null
if base is not null
; otherwise
String.class
.
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Copyright 2007 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.