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: Class IsLastExpression

com.icl.saxon.expr
Class IsLastExpression


java.lang.Object

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  +--com.icl.saxon.expr.Expression

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        +--com.icl.saxon.expr.IsLastExpression


public final class IsLastExpression
extends Expression

position()=last() expression


Fields inherited from class com.icl.saxon.expr.Expression
staticContext
 
Constructor Summary
IsLastExpression(boolean condition)
          Construct a condition that tests position()=last (if condition is true) or position()!=last() (if condition is false).
 
Method Summary
 void display(int level)
          Diagnostic print of expression structure
 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
 int getDependencies()
          Get the dependencies of this expression on the context
 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.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

IsLastExpression


public IsLastExpression(boolean condition)
Construct a condition that tests position()=last (if condition is true) or position()!=last() (if condition is false).
Method Detail

simplify


public Expression simplify()
Description copied from class: Expression
Simplify an expression. Default implementation does nothing.
Overrides:
simplify in class Expression
Following copied from class: com.icl.saxon.expr.Expression
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

getDependencies


public int getDependencies()
Get the dependencies of this expression on the context
Overrides:
getDependencies in class Expression

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

display


public void display(int level)
Diagnostic print of expression structure
Overrides:
display in class Expression