Module jakarta.faces

Package com.sun.faces.facelets.el

Class TagValueExpression

java.lang.Object

jakarta.el.Expression

jakarta.el.ValueExpression

com.sun.faces.facelets.el.TagValueExpression

All Implemented Interfaces:

Externalizable, Serializable

public final class TagValueExpression
extends ValueExpression
implements Externalizable

Version:

$Id$

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
TagValueExpression()
TagValueExpression(TagAttribute tagAttribute, ValueExpression wrapped)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)	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(jakarta.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.
ValueExpression	getWrapped()
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(jakarta.el.ELContext, java.lang.Object) will always fail.
void	readExternal(ObjectInput in)
void	setValue(ELContext context, Object value)	Evaluates the expression relative to the provided context, and sets the result to the provided value.
String	toString()
void	writeExternal(ObjectOutput out)

Methods inherited from class java.lang.Object

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

Constructor Details

TagValueExpression

public TagValueExpression()

TagValueExpression

public TagValueExpression(TagAttribute tagAttribute,
 ValueExpression wrapped)

Method Details

getExpectedType

public Class<?> getExpectedType()

Description copied from class: ValueExpression

Returns the type the result of the expression will be coerced to after evaluation.

Specified by:

getExpectedType in class ValueExpression

Returns:

the expectedType passed to the ExpressionFactory.createValueExpression method that created this ValueExpression.

getType

public Class<?> getType(ELContext context)

Description copied from class: ValueExpression

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(jakarta.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.

Specified by:

getType in class ValueExpression

Parameters:

context - The context of this evaluation.

Returns:

the most general acceptable type; otherwise undefined.

getValue

public Object getValue(ELContext context)

Description copied from class: ValueExpression

Evaluates the expression relative to the provided context, and returns the resulting value.

The resulting value is automatically coerced to the type returned by getExpectedType(), which was provided to the ExpressionFactory when this expression was created.

Specified by:

getValue in class ValueExpression

Parameters:

context - The context of this evaluation.

Returns:

The result of the expression evaluation.

isReadOnly

public boolean isReadOnly(ELContext context)

Description copied from class: ValueExpression

Evaluates the expression relative to the provided context, and returns true if a call to ValueExpression.setValue(jakarta.el.ELContext, java.lang.Object) will always fail.

Specified by:

isReadOnly in class ValueExpression

Parameters:

context - The context of this evaluation.

Returns:

true if the expression is read-only or false if not.

setValue

public void setValue(ELContext context,
 Object value)

Description copied from class: ValueExpression

Evaluates the expression relative to the provided context, and sets the result to the provided value.

Specified by:

setValue in class ValueExpression

Parameters:

context - The context of this evaluation.

value - The new value to be set.

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()

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.

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.

getValueReference

public ValueReference getValueReference(ELContext context)

Description copied from class: ValueExpression

Returns a ValueReference for this expression instance.

Overrides:

getValueReference in class ValueExpression

Parameters:

context - the context of this evaluation

Returns:

the ValueReference 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 Jakarta Expression Language variable, return the ValueReference for the ValueExpression associated with this Jakarta Expression Language variable.

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
ClassNotFoundException

Specified by:

readExternal in interface Externalizable

Throws:

IOException

ClassNotFoundException

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Specified by:

writeExternal in interface Externalizable

Throws:

IOException

getWrapped

public ValueExpression getWrapped()

toString

public String toString()

Overrides:

toString in class Object