public abstract class BooleanExpression extends BinaryExpression implements Negatable
operator
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, UPDATE_METHOD, WATCH_METHOD
Constructor and Description |
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BooleanExpression(Expression p1,
int operator,
Expression p2)
Construct a boolean expression
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Modifier and Type | Method and Description |
---|---|
int |
computeCardinality()
Determine the static cardinality.
|
abstract boolean |
effectiveBooleanValue(XPathContext c)
Evaluate as a boolean.
|
BooleanValue |
evaluateItem(XPathContext context)
Evaluate the expression
|
protected Expression |
forceToBoolean(Expression in) |
java.lang.String |
getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user.
|
ItemType |
getItemType()
Determine the data type of the expression
|
protected OperandRole |
getOperandRole(int arg)
Get the operand role
|
UType |
getStaticUType(UType contextItemType)
Get the static type of the expression as a UType, following precisely the type
inference rules defined in the XSLT 3.0 specification.
|
boolean |
isNegatable(TypeHierarchy th)
Check whether this specific instance of the expression is negatable
|
static void |
listAndComponents(Expression exp,
java.util.List<Expression> list)
Construct a list containing the "anded" subexpressions of an expression:
if the expression is (A and B and C), this returns (A, B, C).
|
abstract Expression |
negate()
Return the negation of this boolean expression, that is, an expression that returns true
when this expression returns false, and vice versa
|
Expression |
optimize(ExpressionVisitor visitor,
ContextItemStaticInfo contextItemType)
Perform optimisation of an expression and its subexpressions.
|
protected abstract Expression |
preEvaluate()
Evaluate the expression statically if either or both operands are literals.
|
Expression |
typeCheck(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Type-check the expression.
|
computeHashCode, computeSpecialProperties, displayOperator, equals, explainExtraAttributes, export, getImplementationMethod, getLhs, getLhsExpression, getOperator, getRhs, getRhsExpression, isAssociative, isCommutative, isInverse, operands, setFlattened, setLhsExpression, setRhsExpression, tag, toShortString, toString
addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, copy, dynamicError, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getConstructType, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getNetCost, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, getStreamerName, hasCompatibleStaticContext, hashCode, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isCallOnSystemFunction, isIdentical, isInstruction, isLiftable, isMultiThreaded, isSameExpression, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, process, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, typeCheckChildren, typeError, unordered, verifyParentPointers, verifyParentPointers
public BooleanExpression(Expression p1, int operator, Expression p2)
public java.lang.String getExpressionName()
getExpressionName
in class Expression
public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
BinaryExpression
typeCheck
in class BinaryExpression
visitor
- an expression visitorcontextInfo
- Information available statically about the context item: whether it is (possibly)
absent; its static type; its streaming posture.XPathException
- if an error is discovered during this phase
(typically a type error)public int computeCardinality()
computeCardinality
in class BinaryExpression
StaticProperty.ALLOWS_ZERO_OR_ONE
,
StaticProperty.EXACTLY_ONE
, StaticProperty.ALLOWS_ONE_OR_MORE
,
StaticProperty.ALLOWS_ZERO_OR_MORE
public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) throws XPathException
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.
optimize
in class BinaryExpression
visitor
- an expression visitorcontextItemType
- 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
XPathException
- if an error is discovered during this phase
(typically a type error)protected abstract Expression preEvaluate()
protected Expression forceToBoolean(Expression in)
public boolean isNegatable(TypeHierarchy th)
isNegatable
in interface Negatable
th
- the type hierarchy, if neededpublic abstract Expression negate()
public BooleanValue evaluateItem(XPathContext context) throws XPathException
evaluateItem
in class Expression
context
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionpublic abstract boolean effectiveBooleanValue(XPathContext c) throws XPathException
effectiveBooleanValue
in class Expression
c
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionpublic ItemType getItemType()
getItemType
in class Expression
public UType getStaticUType(UType contextItemType)
getStaticUType
in class Expression
contextItemType
- public static void listAndComponents(Expression exp, java.util.List<Expression> list)
exp
- the expression to be decomposedlist
- the list to which the subexpressions are to be added.protected OperandRole getOperandRole(int arg)
BinaryExpression
getOperandRole
in class BinaryExpression
arg
- which argument: 0 for the lhs, 1 for the rhsCopyright (c) 2004-2018 Saxonica Limited. All rights reserved.