net.sf.saxon.expr
Class IntegerRangeTest

java.lang.Object
  net.sf.saxon.expr.Expression
      net.sf.saxon.expr.IntegerRangeTest

All Implemented Interfaces:

Serializable, SourceLocator, Container, EvaluableItem, SequenceIterable, InstructionInfoProvider

public class IntegerRangeTest
extends Expression

An IntegerRangeTest is an expression of the form E = N to M where E, N, and M are all expressions of type integer.

See Also:

Serialized Form

Field Summary

Fields inherited from class net.sf.saxon.expr.Expression

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD

Constructor Summary

IntegerRangeTest(Expression value, Expression min, Expression max)
Construct a IntegerRangeTest

Method Summary

int	computeCardinality() Determine the static cardinality
void	display(int level, PrintStream out, Configuration config) Display this instruction as an expression, for diagnostics
Item	evaluateItem(XPathContext c) Evaluate the expression
ItemType	getItemType(TypeHierarchy th) Get the data type of the items returned
Iterator	iterateSubExpressions() Get the immediate sub-expressions of this expression.
Expression	optimize(Optimizer opt, StaticContext env, ItemType contextItemType) Perform optimisation of an expression and its subexpressions.
boolean	replaceSubExpression(Expression original, Expression replacement) Replace one subexpression by a replacement subexpression
Expression	typeCheck(StaticContext env, ItemType contextItemType) Perform type checking of an expression and its subexpressions.

Methods inherited from class net.sf.saxon.expr.Expression

adoptChildExpression, checkPermittedContents, computeDependencies, computeSpecialProperties, computeStaticProperties, doPromotion, effectiveBooleanValue, evaluateAsString, getCardinality, getColumnNumber, getContainingProcedure, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterate, markTailFunctionCalls, process, promote, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, simplify, suppressValidation

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

IntegerRangeTest

public IntegerRangeTest(Expression value,
                        Expression min,
                        Expression max)

Construct a IntegerRangeTest

Method Detail

typeCheck

public Expression typeCheck(StaticContext env,
                            ItemType contextItemType)
                     throws XPathException

Description copied from class: Expression

Perform type checking of an expression and its subexpressions. This is the second phase of static optimization.

This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.

This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.

If the implementation returns a value other than "this", then it is required to ensure that the parent pointer and location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.

Overrides:

typeCheck in class Expression

Parameters:

env - the static context of the expression

contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE

Returns:

the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations

Throws:

StaticError - if an error is discovered during this phase (typically a type error)

XPathException

optimize

public Expression optimize(Optimizer opt,
                           StaticContext env,
                           ItemType contextItemType)
                    throws XPathException

Perform optimisation of an expression and its subexpressions.

This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

Overrides:

optimize in class Expression

Parameters:

opt - the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.

env - the static context of the expression

contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE

Returns:

the original expression, rewritten if appropriate to optimize execution

Throws:

StaticError - if an error is discovered during this phase (typically a type error)

XPathException

getItemType

public ItemType getItemType(TypeHierarchy th)

Get the data type of the items returned

Specified by:

getItemType in class Expression

Parameters:

th -

Returns:

a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)

computeCardinality

public int computeCardinality()

Determine the static cardinality

iterateSubExpressions

public Iterator iterateSubExpressions()

Get the immediate sub-expressions of this expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.

Overrides:

iterateSubExpressions in class Expression

Returns:

an iterator containing the sub-expressions of this expression

replaceSubExpression

public boolean replaceSubExpression(Expression original,
                                    Expression replacement)

Replace one subexpression by a replacement subexpression

Specified by:

replaceSubExpression in interface Container

Overrides:

replaceSubExpression in class Expression

Parameters:

original - the original subexpression

replacement - the replacement subexpression

Returns:

true if the original subexpression is found

evaluateItem

public Item evaluateItem(XPathContext c)
                  throws XPathException

Evaluate the expression

Specified by:

evaluateItem in interface EvaluableItem

Overrides:

evaluateItem in class Expression

Parameters:

c - The context in which the expression is to be evaluated

Returns:

the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence

Throws:

XPathException - if any dynamic error occurs evaluating the expression

display

public void display(int level,
                    PrintStream out,
                    Configuration config)

Display this instruction as an expression, for diagnostics

Specified by:

display in class Expression

Parameters:

level - indentation level for this expression

out - Output destination