|
Préférences
Moteurs de recherche
|
||||||||||||||||||||
JavaTM Platform, Enterprise Edition, v 5.0
javax.el
|
Constructor Summary | |
---|---|
ValueExpression()
|
Method Summary | |
---|---|
abstract Class<?> |
getExpectedType()
Returns the type the result of the expression will be coerced to after evaluation. |
abstract Class<?> |
getType(ELContext context)
Evaluates the expression relative to the provided context, and returns the most general type that is acceptable for an object to be passed as the value parameter in a future call
to the setValue(javax.el.ELContext, java.lang.Object) method. |
abstract Object |
getValue(ELContext context)
Evaluates the expression relative to the provided context, and returns the resulting value. |
abstract boolean |
isReadOnly(ELContext context)
Evaluates the expression relative to the provided context, and returns true if a call to setValue(javax.el.ELContext, java.lang.Object) will
always fail. |
abstract void |
setValue(ELContext context,
Object value)
Evaluates the expression relative to the provided context, and sets the result to the provided value. |
Methods inherited from class javax.el.Expression |
---|
equals, getExpressionString, hashCode, isLiteralText |
Methods inherited from class java.lang.Object |
---|
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
---|
public ValueExpression()
Method Detail |
---|
public abstract Object getValue(ELContext context)
The resulting value is automatically coerced to the type
returned by getExpectedType()
, which was
provided to the ExpressionFactory
when this
expression was created.
context
- The context of this evaluation.
NullPointerException
- if context is null
.
PropertyNotFoundException
- if one of the property
resolutions failed because a specified variable or property
does not exist or is not readable.
ELException
- if an exception was thrown while performing
property or variable resolution. The thrown exception
must be included as the cause property of this exception, if
available.public abstract void setValue(ELContext context, Object value)
context
- The context of this evaluation.value
- The new value to be set.
NullPointerException
- if context is null
.
PropertyNotFoundException
- if one of the property
resolutions failed because a specified variable or property
does not exist or is not readable.
PropertyNotWritableException
- if the final variable or
property resolution failed because the specified
variable or property is not writable.
ELException
- if an exception was thrown while attempting to
set the property or variable. The thrown exception
must be included as the cause property of this exception, if
available.public abstract boolean isReadOnly(ELContext context)
true
if a call to setValue(javax.el.ELContext, java.lang.Object)
will
always fail.
context
- The context of this evaluation.
true
if the expression is read-only or
false
if not.
NullPointerException
- if context is null
.
PropertyNotFoundException
- if one of the property
resolutions failed because a specified variable or property
does not exist or is not readable.
ELException
- if an exception was thrown while performing
property or variable resolution. The thrown exception
must be included as the cause property of this exception, if
available.
* @throws NullPointerException if context is null
public abstract Class<?> getType(ELContext context)
value
parameter in a future call
to the setValue(javax.el.ELContext, java.lang.Object)
method.
This is not always the same as getValue().getClass()
.
For example, in the case of an expression that references an
array element, the getType
method will return the
element type of the array, which might be a superclass of the type
of the actual element that is currently in the specified
array element.
context
- The context of this evaluation.
NullPointerException
- if context is null
.
PropertyNotFoundException
- if one of the property
resolutions failed because a specified variable or property
does not exist or is not readable.
ELException
- if an exception was thrown while performing
property or variable resolution. The thrown exception
must be included as the cause property of this exception, if
available.public abstract Class<?> getExpectedType()
expectedType
passed to the
ExpressionFactory.createValueExpression
method
that created this ValueExpression
.