public abstract class ForwardingValueExpression extends ValueExpression
Constructor and Description |
---|
ForwardingValueExpression() |
Modifier and Type | Method and Description |
---|---|
protected abstract ValueExpression |
delegate() |
boolean |
equals(Object obj)
Determines whether the specified object is equal to this
Expression . |
Class |
getExpectedType()
Returns the type the result of the expression will be coerced to
after evaluation.
|
String |
getExpressionString()
Returns the original String used to create this
Expression ,
unmodified. |
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 ValueExpression.setValue(javax.el.ELContext, java.lang.Object) method. |
Object |
getValue(ELContext context)
Evaluates the expression relative to the provided context, and
returns the resulting value.
|
ValueReference |
getValueReference(ELContext context)
Returns a
ValueReference for this expression instance. |
int |
hashCode()
Returns the hash code for this
Expression . |
boolean |
isLiteralText()
Returns whether this expression was created from only literal text.
|
boolean |
isReadOnly(ELContext context)
Evaluates the expression relative to the provided context, and
returns
true if a call to ValueExpression.setValue(javax.el.ELContext, java.lang.Object) will
always fail. |
void |
setValue(ELContext context,
Object value)
Evaluates the expression relative to the provided context, and
sets the result to the provided value.
|
String |
toString() |
protected abstract ValueExpression delegate()
public Class getExpectedType()
ValueExpression
getExpectedType
in class ValueExpression
expectedType
passed to the
ExpressionFactory.createValueExpression
method
that created this ValueExpression
.public Class getType(ELContext context)
ValueExpression
value
parameter in a future call
to the ValueExpression.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.
getType
in class ValueExpression
context
- The context of this evaluation.public Object getValue(ELContext context)
ValueExpression
The resulting value is automatically coerced to the type
returned by getExpectedType()
, which was
provided to the ExpressionFactory
when this
expression was created.
getValue
in class ValueExpression
context
- The context of this evaluation.public boolean isReadOnly(ELContext context)
ValueExpression
true
if a call to ValueExpression.setValue(javax.el.ELContext, java.lang.Object)
will
always fail.isReadOnly
in class ValueExpression
context
- The context of this evaluation.true
if the expression is read-only or
false
if not.public void setValue(ELContext context, Object value)
ValueExpression
setValue
in class ValueExpression
context
- The context of this evaluation.value
- The new value to be set.public String getExpressionString()
Expression
Expression
,
unmodified.
This is used for debugging purposes but also for the purposes of comparison (e.g. to ensure the expression in a configuration file has not changed).
This method does not provide sufficient information to
re-create an expression. Two different expressions can have exactly
the same expression string but different function mappings.
Serialization should be used to save and restore the state of an
Expression
.
getExpressionString
in class Expression
public boolean isLiteralText()
Expression
This method must return true
if and only if the
expression string this expression was created from contained no
unescaped EL delimeters (${...}
or
#{...}
).
isLiteralText
in class Expression
true
if this expression was created from only
literal text; false
otherwise.public boolean equals(Object obj)
Expression
Expression
.
The result is true
if and only if the argument is
not null
, is an Expression
object that
is the of the same type (ValueExpression
or
MethodExpression
), and has an identical parsed
representation.
Note that two expressions can be equal if their expression
Strings are different. For example, ${fn1:foo()}
and ${fn2:foo()}
are equal if their corresponding
FunctionMapper
s mapped fn1:foo
and
fn2:foo
to the same method.
equals
in class Expression
obj
- the Object
to test for equality.true
if obj
equals this
Expression
; false
otherwise.Hashtable
,
Object.equals(java.lang.Object)
public int hashCode()
Expression
Expression
.
See the note in the Expression.equals(java.lang.Object)
method on how two expressions
can be equal if their expression Strings are different. Recall that
if two objects are equal according to the equals(Object)
method, then calling the hashCode
method on each of the
two objects must produce the same integer result. Implementations must
take special note and implement hashCode
correctly.
hashCode
in class Expression
Expression
.Expression.equals(java.lang.Object)
,
Hashtable
,
Object.hashCode()
public ValueReference getValueReference(ELContext context)
ValueExpression
ValueReference
for this expression instance.getValueReference
in class ValueExpression
context
- the context of this evaluationValueReference
for this
ValueExpression
, or null
if this
ValueExpression
is not a reference to
a base (null or non-null) and a property.
If the base is null, and the property is a EL variable, return
the ValueReference
for the
ValueExpression
associated with this EL variable.Copyright © 2013 Seam Framework. All Rights Reserved.