Module jakarta.faces

Package com.sun.faces.facelets.el

Class ContextualCompositeMethodExpression

java.lang.Object

jakarta.el.Expression

jakarta.el.MethodExpression

com.sun.faces.facelets.el.ContextualCompositeMethodExpression

All Implemented Interfaces:

Serializable

public class ContextualCompositeMethodExpression
extends MethodExpression

This specialized MethodExpression enables the evaluation of composite component expressions. Instances of this expression will be created when TagAttributeImpl.getValueExpression(jakarta.faces.view.facelets.FaceletContext, Class) is invoked and the expression represents a composite component expression (i.e. #{cc.[properties]}).

It's important to note that these MethodExpressions are context sensitive in that they leverage the location in which they were referenced in order to push the proper composite component to the evaluation context prior to evaluating the expression itself.

Here's an example:

 Using Page test.xhtml
 ---------------------------------
    <ez:comp1 do="#{bean.action}" />


 comp1.xhtml
 ---------------------------------
 <composite:interface>
    <composite:attribute name="do" method-signature="String f()" required="true" />
 </composite:interface>
 <composite:implementation>
    <ez:nesting>
       <h:commandButton value="Click Me!" action="#{cc.attrs.do} />
    </ez:nesting>
 </composite:implementation>

 nesting.xhtml
 ---------------------------------
 <composite:interface />
 <composite:implementation>
    <composite:insertChildren>
 </composite:implementation>
 

When commandButton is clicked, the ContextualCompositeMethodExpression first is looked up by

invalid reference

com.sun.faces.facelets.tag.TagAttributeImpl.AttributeLookupMethodExpression

which results an instance of ContextualCompositeMethodExpression. When this ContextualCompositeMethodExpression is invoked, the Location object necessary to find the proper composite component will be derived from source ValueExpression provided at construction time. Using the derived Location, we can find the composite component that matches 'owns' the template in which the expression was defined in by comparing the path of the Location with the name and library of the Resource instance associated with each composite component. If a matching composite component is found, it will be made available to the EL by calling CompositeComponentStackManager.push(jakarta.faces.component.UIComponent).

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
ContextualCompositeMethodExpression(ValueExpression source, MethodExpression delegate)
ContextualCompositeMethodExpression(Location location, MethodExpression delegate)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)	Determines whether the specified object is equal to this Expression.
String	getExpressionString()	Returns the original String used to create this Expression, unmodified.
MethodInfo	getMethodInfo(ELContext elContext)	Evaluates the expression relative to the provided context, and returns information about the actual referenced method.
int	hashCode()	Returns the hash code for this Expression.
Object	invoke(ELContext elContext, Object[] objects)	If a String literal is specified as the expression, returns the String literal coerced to the expected return type of the method signature.
boolean	isLiteralText()	Returns whether this expression was created from only literal text.

Methods inherited from class jakarta.el.MethodExpression

getMethodReference, isParametersProvided

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ContextualCompositeMethodExpression

public ContextualCompositeMethodExpression(ValueExpression source,
 MethodExpression delegate)

ContextualCompositeMethodExpression

public ContextualCompositeMethodExpression(Location location,
 MethodExpression delegate)

Method Details

getMethodInfo

public MethodInfo getMethodInfo(ELContext elContext)

Description copied from class: MethodExpression

Evaluates the expression relative to the provided context, and returns information about the actual referenced method.

Specified by:

getMethodInfo in class MethodExpression

Parameters:

elContext - The context of this evaluation

Returns:

an instance of MethodInfo containing information about the method the expression evaluated to.

invoke

public Object invoke(ELContext elContext,
 Object[] objects)

Description copied from class: MethodExpression

If a String literal is specified as the expression, returns the String literal coerced to the expected return type of the method signature. An ELException is thrown if expectedReturnType is void or if the coercion of the String literal to the expectedReturnType yields an error (see Section "1.18 Type Conversion" of the Jakarta Expression Language specification). If not a String literal, evaluates the expression relative to the provided context, invokes the method that was found using the supplied parameters, and returns the result of the method invocation. Any parameters passed to this method is ignored if isLiteralText() or isParametersProvided() is true.

Specified by:

invoke in class MethodExpression

Parameters:

elContext - The context of this evaluation.

objects - The parameters to pass to the method, or null if no parameters.

Returns:

the result of the method invocation (null if the method has a void return type).

getExpressionString

public String getExpressionString()

Description copied from class: Expression

Returns the original String used to create this 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.

Specified by:

getExpressionString in class Expression

Returns:

The original expression String.

equals

public boolean equals(Object o)

Description copied from class: Expression

Determines whether the specified object is equal to this 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 FunctionMappers mapped fn1:foo and fn2:foo to the same method.

Specified by:

equals in class Expression

Parameters:

o - the Object to test for equality.

Returns:

true if obj equals this Expression; false otherwise.

See Also:

• Hashtable
• Object.equals(java.lang.Object)

hashCode

public int hashCode()

Description copied from class: Expression

Returns the hash code for this 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.

Specified by:

hashCode in class Expression

Returns:

The hash code for this Expression.

See Also:

• Expression.equals(java.lang.Object)
• Hashtable
• Object.hashCode()

isLiteralText

public boolean isLiteralText()

Description copied from class: Expression

Returns whether this expression was created from only literal text.

This method must return true if and only if the expression string this expression was created from contained no unescaped Jakarta Expression Language delimeters (${...} or #{...}).

Specified by:

isLiteralText in class Expression

Returns:

true if this expression was created from only literal text; false otherwise.