| java.lang.Object
 javax.el.Expression
All known Subclasses: javax.el.ValueExpression, javax.el.MethodExpression,
| Expression | | abstract public class Expression implements Serializable(Code) | | Base class for the expression subclasses
ValueExpression and
MethodExpression , implementing characterstics common to both.
All expressions must implement the equals() and
hashCode() methods so that two expressions can be compared
for equality. They are redefined abstract in this class to force their
implementation in subclasses.
All expressions must also be Serializable so that they
can be saved and restored.
Expressions are also designed to be immutable so
that only one instance needs to be created for any given expression
String /
FunctionMapper . This allows a container to pre-create
expressions and not have to re-parse them each time they are evaluated.
since:
JSP 2.1 |
| Method Summary | |
| abstract public boolean | equals(Object obj)
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. | | abstract public String | getExpressionString()
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. | | abstract public int | hashCode()
Returns the hash code for this Expression.
See the note in the
Expression.equals method on how two expressions
can be equal if their expression Strings are different. | | abstract public boolean | isLiteralText()
Returns whether this expression was created from only literal text. |
| equals | | abstract public boolean equals(Object obj)(Code) | | 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 ${fn2:foo()} are equal if their corresponding
FunctionMappers mapped fn1:foo and
fn2:foo to the same method.
Parameters:
obj - the Object to test for equality. true if obj equals thisExpression; false otherwise.
See Also: java.util.Hashtable
See Also: java.lang.Object.equals(java.lang.Object) |
| getExpressionString | | abstract public String getExpressionString()(Code) | | Returns the original String used to create this Expression,
unmodified.
This is used for debugging purposes but also for the purposes
of comparison (e.g. to ensure the expression in a configuration
file has not changed).
This method does not provide sufficient information to
re-create an expression. Two different expressions can have exactly
the same expression string but different function mappings.
Serialization should be used to save and restore the state of an
Expression.
The original expression String. |
| hashCode | | abstract public int hashCode()(Code) | | Returns the hash code for this Expression.
See the note in the
Expression.equals method on how two expressions
can be equal if their expression Strings are different. Recall that
if two objects are equal according to the equals(Object)
method, then calling the hashCode method on each of the
two objects must produce the same integer result. Implementations must
take special note and implement hashCode correctly.
The hash code for this Expression.
See Also: Expression.equals
See Also: java.util.Hashtable
See Also: java.lang.Object.hashCode |
| isLiteralText | | abstract public boolean isLiteralText()(Code) | | Returns whether this expression was created from only literal text.
This method must return true if and only if the
expression string this expression was created from contained no
unescaped EL delimeters (${...} or
#{...}).
true if this expression was created from onlyliteral text; false otherwise. |
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