|
Oracle Fusion Middleware Java API Reference for Oracle ADF Mobile Client 11g Release 1 (11.1.1) E17503-02 |
||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |
java.lang.Objectoracle.adfnmc.el.CompositeELResolver
public class CompositeELResolver
Maintains an ordered composite list of child ELResolver
s.
Though only a single ELResolver
is associated with an ELContext
,
there are usually multiple resolvers considered for any given variable or property resolution.
ELResolver
s are combined together using a CompositeELResolver
, to
define rich semantics for evaluating an expression.
For the getValue(oracle.adfnmc.el.ELContext, java.lang.Object, java.lang.Object)
, getType(oracle.adfnmc.el.ELContext, java.lang.Object, java.lang.Object)
, setValue(oracle.adfnmc.el.ELContext, java.lang.Object, java.lang.Object, java.lang.Object)
and isReadOnly(oracle.adfnmc.el.ELContext, java.lang.Object, java.lang.Object)
methods,
an ELResolver
is not responsible for resolving all possible (base, property)
pairs. In fact, most resolvers will only handle a base
of a single type. To
indicate that a resolver has successfully resolved a particular (base, property) pair, it must
set the propertyResolved
property of the ELContext
to
true
. If it could not handle the given pair, it must leave this property alone.
The caller must ignore the return value of the method if propertyResolved
is
false
.
The CompositeELResolver
initializes the ELContext.propertyResolved
flag to false
, and uses it as a stop condition for iterating through its
component resolvers.
The ELContext.propertyResolved
flag is not used for the design-time methods
#getFeatureDescriptors
and #getCommonPropertyType
. Instead, results are
collected and combined from all child ELResolver
s for these methods.
ELContext
,
ELResolver
Field Summary |
---|
Fields inherited from interface oracle.adfnmc.el.ELResolver |
---|
RESOLVABLE_AT_DESIGN_TIME, TYPE |
Constructor Summary | |
---|---|
CompositeELResolver()
|
Method Summary | |
---|---|
void |
add(ELResolver elResolver)
Adds the given resolver to the list of component resolvers. |
java.lang.Class |
getType(ELContext context,
java.lang.Object base,
java.lang.Object property)
For a given base and property , attempts to identify the most
general type that is acceptable for an object to be passed as the value
parameter in a future call to the setValue(oracle.adfnmc.el.ELContext, java.lang.Object, java.lang.Object, java.lang.Object) method. |
java.lang.Object |
getValue(ELContext context,
java.lang.Object base,
java.lang.Object property)
Attempts to resolve the given property object on the given base
object by querying all component resolvers. |
boolean |
isReadOnly(ELContext context,
java.lang.Object base,
java.lang.Object property)
For a given base and property , attempts to determine whether a
call to setValue(oracle.adfnmc.el.ELContext, java.lang.Object, java.lang.Object, java.lang.Object) will always fail. |
void |
setValue(ELContext context,
java.lang.Object base,
java.lang.Object property,
java.lang.Object val)
Attempts to set the value of the given property object on the given
base object. |
Methods inherited from class java.lang.Object |
---|
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
---|
public CompositeELResolver()
Method Detail |
---|
public void add(ELResolver elResolver)
Resolvers are consulted in the order in which they are added.
elResolver
- The component resolver to add.
java.lang.NullPointerException
- If the provided resolver is null
.public java.lang.Object getValue(ELContext context, java.lang.Object base, java.lang.Object property)
property
object on the given base
object by querying all component resolvers.
If this resolver handles the given (base, property) pair, the propertyResolved
property of the ELContext
object must be set to true
by the
resolver, before returning. If this property is not true
after this method is
called, the caller should ignore the return value.
First, propertyResolved
is set to false
on the provided
ELContext
.
Next, for each component resolver in this composite:
getValue()
method is called, passing in the provided
context
, base
and property
.ELContext
's propertyResolved
flag is
false
then iteration continues.getValue()
is returned by this method.
If none of the component resolvers were able to perform this operation, the value
null
is returned and the propertyResolved
flag remains set to
false
Any exception thrown by component resolvers during the iteration is propagated to the caller of this method.
getValue
in interface ELResolver
context
- The context of this evaluation.base
- The base object whose property value is to be returned, or null
to
resolve a top-level variable.property
- The property or variable to be resolved.
propertyResolved
property of ELContext
was set
to true
, then the result of the variable or property resolution;
otherwise undefined.
java.lang.NullPointerException
- if context is null
PropertyNotFoundException
- if the given (base, property) pair is handled by this ELResolver
but the specified variable or property does not exist or is not readable.
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, java.lang.Object base, java.lang.Object property, java.lang.Object val)
property
object on the given
base
object. All component resolvers are asked to attempt to set the value.
If this resolver handles the given (base, property) pair, the propertyResolved
property of the ELContext
object must be set to true
by the
resolver, before returning. If this property is not true
after this method is
called, the caller can safely assume no value has been set.
First, propertyResolved
is set to false
on the provided
ELContext
.
Next, for each component resolver in this composite:
setValue()
method is called, passing in the provided
context
, base
, property
and value
.ELContext
's propertyResolved
flag is
false
then iteration continues.
If none of the component resolvers were able to perform this operation, the
propertyResolved
flag remains set to false
Any exception thrown by component resolvers during the iteration is propagated to the caller of this method.
setValue
in interface ELResolver
context
- The context of this evaluation.base
- The base object whose property value is to be set, or null
to set a
top-level variable.property
- The property or variable to be set.val
- The value to set the property or variable to.
java.lang.NullPointerException
- if context is null
PropertyNotFoundException
- if the given (base, property) pair is handled by this ELResolver
but the specified variable or property does not exist.
PropertyNotWritableException
- if the given (base, property) pair is handled by this ELResolver
but 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 java.lang.Class getType(ELContext context, java.lang.Object base, java.lang.Object property)
base
and property
, attempts to identify the most
general type that is acceptable for an object to be passed as the value
parameter in a future call to the setValue(oracle.adfnmc.el.ELContext, java.lang.Object, java.lang.Object, java.lang.Object)
method. The result is obtained by
querying all component resolvers.
If this resolver handles the given (base, property) pair, the propertyResolved
property of the ELContext
object must be set to true
by the
resolver, before returning. If this property is not true
after this method is
called, the caller should ignore the return value.
First, propertyResolved
is set to false
on the provided
ELContext
.
Next, for each component resolver in this composite:
getType()
method is called, passing in the provided
context
, base
and property
.ELContext
's propertyResolved
flag is
false
then iteration continues.getType()
is returned by this method.
If none of the component resolvers were able to perform this operation, the value
null
is returned and the propertyResolved
flag remains set to
false
Any exception thrown by component resolvers during the iteration is propagated to the caller of this method.
getType
in interface ELResolver
context
- The context of this evaluation.base
- The base object whose property value is to be analyzed, or null
to
analyze a top-level variable.property
- The property or variable to return the acceptable type for.
propertyResolved
property of ELContext
was set
to true
, then the most general acceptable type; otherwise undefined.
java.lang.NullPointerException
- if context is null
PropertyNotFoundException
- if the given (base, property) pair is handled by this ELResolver
but the specified variable or property does not exist or is not readable.
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, java.lang.Object base, java.lang.Object property)
base
and property
, attempts to determine whether a
call to setValue(oracle.adfnmc.el.ELContext, java.lang.Object, java.lang.Object, java.lang.Object)
will always fail. The result is obtained by querying all component
resolvers.
If this resolver handles the given (base, property) pair, the propertyResolved
property of the ELContext
object must be set to true
by the
resolver, before returning. If this property is not true
after this method is
called, the caller should ignore the return value.
First, propertyResolved
is set to false
on the provided
ELContext
.
Next, for each component resolver in this composite:
isReadOnly()
method is called, passing in the provided
context
, base
and property
.ELContext
's propertyResolved
flag is
false
then iteration continues.isReadOnly()
is returned by this method.
If none of the component resolvers were able to perform this operation, the value
false
is returned and the propertyResolved
flag remains set to
false
Any exception thrown by component resolvers during the iteration is propagated to the caller of this method.
isReadOnly
in interface ELResolver
context
- The context of this evaluation.base
- The base object whose property value is to be analyzed, or null
to
analyze a top-level variable.property
- The property or variable to return the read-only status for.
propertyResolved
property of ELContext
was set
to true
, then true
if the property is read-only or
false
if not; otherwise undefined.
java.lang.NullPointerException
- if context is null
PropertyNotFoundException
- if the given (base, property) pair is handled by this ELResolver
but the specified variable or property does not exist.
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.
|
Oracle Fusion Middleware Java API Reference for Oracle ADF Mobile Client 11g Release 1 (11.1.1) E17503-02 |
||||||||
PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD |