com.icl.saxon.expr
Class BooleanExpression

java.lang.Object
  |
  +--com.icl.saxon.expr.Expression
        |
        +--com.icl.saxon.expr.BinaryExpression
              |
              +--com.icl.saxon.expr.BooleanExpression

class BooleanExpression
extends BinaryExpression

Boolean expression: two booleans combined using AND or OR


Fields inherited from class com.icl.saxon.expr.BinaryExpression
operator, p1, p2
 
Fields inherited from class com.icl.saxon.expr.Expression
staticContext
 
Constructor Summary
BooleanExpression()
           
BooleanExpression(Expression p1, int operator, Expression p2)
           
 
Method Summary
 Value evaluate(Context c)
          Evaluate an expression.
 boolean evaluateAsBoolean(Context c)
          Evaluate an expression as a Boolean.
The result of x.evaluateAsBoolean(c) must be equivalent to x.evaluate(c).asBoolean(); but optimisations are possible when it is known that a boolean result is required, especially in the case of a NodeSet.
 int getDataType()
          Determine the data type of the expression
 Expression reduce(int dependencies, Context context)
          Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
 Expression simplify()
          Simplify an expression
 
Methods inherited from class com.icl.saxon.expr.BinaryExpression
display, getDependencies, setDetails
 
Methods inherited from class com.icl.saxon.expr.Expression
containsReferences, enumerate, evaluateAsNodeSet, evaluateAsNumber, evaluateAsString, getStaticContext, indent, isContextDocumentNodeSet, make, outputStringValue, setStaticContext, usesCurrent
 
Methods inherited from class java.lang.Object
, clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

BooleanExpression

public BooleanExpression()

BooleanExpression

public BooleanExpression(Expression p1,
                         int operator,
                         Expression p2)
Method Detail

simplify

public Expression simplify()
                    throws XPathException
Description copied from class: BinaryExpression
Simplify an expression
Overrides:
simplify in class BinaryExpression
Following copied from class: com.icl.saxon.expr.BinaryExpression
Returns:
the simplified expression

evaluate

public Value evaluate(Context c)
               throws XPathException
Description copied from class: Expression
Evaluate an expression.
Overrides:
evaluate in class Expression
Following copied from class: com.icl.saxon.expr.Expression
Parameters:
context - The context in which the expression is to be evaluated
Returns:
the value of the expression, evaluated in the current context

evaluateAsBoolean

public boolean evaluateAsBoolean(Context c)
                          throws XPathException
Description copied from class: Expression
Evaluate an expression as a Boolean.
The result of x.evaluateAsBoolean(c) must be equivalent to x.evaluate(c).asBoolean(); but optimisations are possible when it is known that a boolean result is required, especially in the case of a NodeSet.
Overrides:
evaluateAsBoolean in class Expression
Following copied from class: com.icl.saxon.expr.Expression
Parameters:
context - The context in which the expression is to be evaluated
Returns:
the value of the expression, evaluated in the current context

getDataType

public int getDataType()
Determine the data type of the expression
Overrides:
getDataType in class Expression
Returns:
Value.BOOLEAN

reduce

public Expression reduce(int dependencies,
                         Context context)
                  throws XPathException
Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
Overrides:
reduce in class Expression
Parameters:
dependencies - The dependencies to be removed
context - The context to be used for the partial evaluation
Returns:
a new expression that does not have any of the specified dependencies