de.odysseus.el
Class ObjectValueExpression

java.lang.Object
  javax.el.Expression
      javax.el.ValueExpression
          de.odysseus.el.ObjectValueExpression

All Implemented Interfaces:

java.io.Serializable

public final class ObjectValueExpression
extends ValueExpression

Object wrapper expression.

Author:

Christoph Beck

See Also:

Serialized Form

Constructor Summary

ObjectValueExpression(java.lang.Object object, java.lang.Class<?> type)
Wrap an object into a value expression.

Method Summary

boolean	equals(java.lang.Object obj) Two object value expressions are equal if and only if their wrapped objects are equal.
java.lang.Class<?>	getExpectedType() Returns the type the result of the expression will be coerced to after evaluation.
java.lang.String	getExpressionString() Answer null.
java.lang.Class<?>	getType(ELContext context) Answer null.
java.lang.Object	getValue(ELContext context) Answer the wrapped object, coerced to the expected type.
int	hashCode() Returns the hash code for this Expression.
boolean	isLiteralText() Answer false.
boolean	isReadOnly(ELContext context) Answer true.
void	setValue(ELContext context, java.lang.Object value) Throw an exception.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

ObjectValueExpression

public ObjectValueExpression(java.lang.Object object,
                             java.lang.Class<?> type)

Wrap an object into a value expression.

Parameters:

object - the object to wrap

type - the expected type this object will be coerced in getValue(ELContext).

Method Detail

equals

public boolean equals(java.lang.Object obj)

Two object value expressions are equal if and only if their wrapped objects are equal.

Specified by:

equals in class Expression

Parameters:

obj - 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()

getValue

public java.lang.Object getValue(ELContext context)

Answer the wrapped object, coerced to the expected type.

Specified by:

getValue in class ValueExpression

Parameters:

context - The context of this evaluation.

Returns:

The result of the expression evaluation.

getExpressionString

public java.lang.String getExpressionString()

Answer null.

Specified by:

getExpressionString in class Expression

Returns:

The original expression String.

isLiteralText

public boolean isLiteralText()

Answer false.

Specified by:

isLiteralText in class Expression

Returns:

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

getType

public java.lang.Class<?> getType(ELContext context)

Answer null.

Specified by:

getType in class ValueExpression

Parameters:

context - The context of this evaluation.

Returns:

the most general acceptable type; otherwise undefined.

isReadOnly

public boolean isReadOnly(ELContext context)

Answer true.

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,
                     java.lang.Object value)

Throw an exception.

Specified by:

setValue in class ValueExpression

Parameters:

context - The context of this evaluation.

value - The new value to be set.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

getExpectedType

public java.lang.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.