org.jaxen.expr
Interface Predicate

All Superinterfaces:
Serializable

public interface Predicate
extends Serializable

Represents an XPath predicate such as [position() = last()]. This is production 8 and 9 in the XPath 1.0 specification:

 [8] Predicate     ::= '[' PredicateExpr ']'   
 [9] PredicateExpr ::= Expr


Method Summary
 Object evaluate(Context context)
          Evaluates this predicate's expression and returns the result.
 Expr getExpr()
          Returns the expression in this predicate.
 String getText()
          Returns the string form of the predicate, including the square brackets.
 void setExpr(Expr expr)
          Change the expression used by this predicate.
 void simplify()
          Simplify the expression in this predicate.
 

Method Detail

getExpr

Expr getExpr()
Returns the expression in this predicate.

Returns:
the expression between the brackets

setExpr

void setExpr(Expr expr)
Change the expression used by this predicate.

Parameters:
expr - the new expression

simplify

void simplify()
Simplify the expression in this predicate.

See Also:
Expr.simplify()

getText

String getText()
Returns the string form of the predicate, including the square brackets.

Returns:
the bracketed form of this predicate

evaluate

Object evaluate(Context context)
                throws JaxenException
Evaluates this predicate's expression and returns the result. The result will be a java.lang.Double for expressions that return a number, a java.lang.String for expressions that return a string, a java.lang.Boolean for expressions that return a boolean, and a java.util.List for expressions that return a node-set. In the latter case, the elements of the list are the actual objects from the source document model. Copies are not made.

Parameters:
context - the context in which the expression is evaluated
Returns:
an object representing the result of the evaluation
Throws:
JaxenException
See Also:
Expr.evaluate(Context)


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