public class Choose extends Instruction
Modifier and Type | Field and Description |
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static OperandRole |
CHOICE_ACTION |
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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Choose(Expression[] conditions,
Expression[] actions)
Construct an xsl:choose instruction
|
Modifier and Type | Method and Description |
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java.lang.Iterable<Operand> |
actions() |
PathMap.PathMapNodeSet |
addToPathMap(PathMap pathMap,
PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap.
|
boolean |
allowExtractingCommonSubexpressions()
Ask whether common subexpressions found in the operands of this expression can
be extracted and evaluated outside the expression itself.
|
void |
atomizeActions()
Atomize all the action expressions
|
void |
checkForUpdatingSubexpressions()
Check to ensure that this expression does not contain any updating subexpressions.
|
void |
checkPermittedContents(SchemaType parentType,
boolean whole)
Check that any elements and attributes constructed or returned by this expression are acceptable
in the content model of a given complex type.
|
int |
computeCardinality()
Compute the cardinality of the sequence returned by evaluating this instruction
|
int |
computeSpecialProperties()
Get the static properties of this expression (other than its type).
|
java.lang.Iterable<Operand> |
conditions() |
Expression |
copy(RebindingMap rebindings)
Copy an expression.
|
Item |
evaluateItem(XPathContext context)
Evaluate an expression as a single item.
|
void |
evaluatePendingUpdates(XPathContext context,
PendingUpdateList pul)
Evaluate an updating expression, adding the results to a Pending Update List.
|
void |
export(ExpressionPresenter out)
Diagnostic print of expression structure.
|
Expression |
getAction(int i)
Get i'th action to be performed
|
Operand |
getActionOperand(int i)
Get i'th action operand
|
Expression |
getCondition(int i) |
java.lang.String |
getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user.
|
int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
|
int |
getInstructionNameCode()
Get the name of this instruction for diagnostic and tracing purposes
We assume that if there was
only one condition then it was an xsl:if; this is not necessarily so, but
it's adequate for tracing purposes.
|
ItemType |
getItemType()
Get the item type of the items returned by evaluating this instruction
|
int |
getNumberOfConditions() |
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.
|
java.lang.String |
getStreamerName()
Get the (partial) name of a class that supports streaming of this kind of expression
|
boolean |
implementsStaticTypeCheck()
Determine whether this expression implements its own method for static type checking
|
boolean |
isInstruction()
Ask whether this expression is an instruction.
|
static boolean |
isSingleBranchChoice(Expression exp)
Test whether an expression is a single-branch choose, that is, an expression of the form
if (condition) then exp else ()
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boolean |
isUpdatingExpression()
Determine whether this is an updating expression as defined in the XQuery update specification
|
boolean |
isVacuousExpression()
Determine whether this is a vacuous expression as defined in the XQuery update specification
|
SequenceIterator |
iterate(XPathContext context)
Return an Iterator to iterate over the values of a sequence.
|
static Expression |
makeConditional(Expression condition,
Expression thenExp)
Make a simple conditional expression (if (condition) then (thenExp) else ()
|
static Expression |
makeConditional(Expression condition,
Expression thenExp,
Expression elseExp)
Make a simple conditional expression (if (condition) then (thenExp) else (elseExp)
|
int |
markTailFunctionCalls(StructuredQName qName,
int arity)
Mark tail-recursive calls on functions.
|
boolean |
mayCreateNewNodes()
Determine whether this instruction creates new nodes.
|
java.lang.Iterable<Operand> |
operands()
Get the immediate sub-expressions of this expression, with information about the relationship
of each expression to its parent expression.
|
Expression |
optimize(ExpressionVisitor visitor,
ContextItemStaticInfo contextItemType)
Perform optimisation of an expression and its subexpressions.
|
TailCall |
processLeavingTail(XPathContext context)
Process this instruction, that is, choose an xsl:when or xsl:otherwise child
and process it.
|
void |
setAction(int i,
Expression action) |
void |
setCondition(int i,
Expression condition) |
void |
setInstruction(boolean inst)
Say whether this choose expression originates as an XSLT instruction
|
Expression |
simplify()
Simplify an expression.
|
int |
size() |
Expression |
staticTypeCheck(SequenceType req,
boolean backwardsCompatible,
RoleDiagnostic role,
ExpressionVisitor visitor)
Static type checking for conditional expressions is delegated to the expression itself,
and is performed separately on each branch of the conditional, so that dynamic checks are
added only on those branches where the check is actually required.
|
java.lang.String |
toShortString()
Produce a short string identifying the expression for use in error messages
|
java.lang.String |
toString()
The toString() method for an expression attempts to give a representation of the expression
in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath.
|
Expression |
typeCheck(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Perform type checking of an expression and its subexpressions.
|
Expression |
unordered(boolean retainAllNodes,
boolean forStreaming)
Replace this expression by a simpler expression that delivers the results without regard
to order.
|
alwaysCreatesNewNodes, assembleParams, assembleTunnelParams, dynamicError, evaluateAsString, getConstructType, getInstructionName, getNetCost, getSourceLocator, isXSLT, process, someOperandCreatesNewNodes
adoptChildExpression, checkedOperands, computeDependencies, computeHashCode, computeStaticProperties, dynamicError, effectiveBooleanValue, explain, getCardinality, getConfiguration, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, hasCompatibleStaticContext, hashCode, hasVariableBinding, identityHashCode, isCallOn, isCallOnSystemFunction, isIdentical, isLiftable, isMultiThreaded, isSameExpression, isStaticPropertiesKnown, isSubtreeExpression, operandList, operandSparseList, optimizeChildren, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplifyChildren, suppressValidation, toPattern, typeCheckChildren, typeError, verifyParentPointers, verifyParentPointers
public static final OperandRole CHOICE_ACTION
public Choose(Expression[] conditions, Expression[] actions)
conditions
- the conditions to be tested, in orderactions
- the actions to be taken when the corresponding condition is truepublic static Expression makeConditional(Expression condition, Expression thenExp, Expression elseExp)
condition
- the condition to be testedthenExp
- the expression to be evaluated if the condition is trueelseExp
- the expression to be evaluated if the condition is falsepublic static Expression makeConditional(Expression condition, Expression thenExp)
condition
- the condition to be testedthenExp
- the expression to be evaluated if the condition is truepublic void setInstruction(boolean inst)
inst
- true if this is an xsl:choose or xsl:if instructionpublic boolean isInstruction()
isInstruction
in class Instruction
public int size()
public static boolean isSingleBranchChoice(Expression exp)
exp
- the expression to be testedpublic int getNumberOfConditions()
public Expression getCondition(int i)
public void setCondition(int i, Expression condition)
public java.lang.Iterable<Operand> conditions()
public Operand getActionOperand(int i)
i
- the action numberpublic Expression getAction(int i)
i
- the action numberpublic void setAction(int i, Expression action)
public java.lang.Iterable<Operand> actions()
public java.lang.Iterable<Operand> operands()
Expression
If the expression is a Callable, then it is required that the order of the operands returned by this function is the same as the order of arguments supplied to the corresponding call() method.
operands
in class Instruction
public boolean allowExtractingCommonSubexpressions()
allowExtractingCommonSubexpressions
in class Expression
public void atomizeActions()
public int getInstructionNameCode()
getInstructionNameCode
in class Instruction
public Expression simplify() throws XPathException
simplify
in class Expression
XPathException
- if an error is discovered during expression
rewritingpublic Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
Expression
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.
typeCheck
in class Expression
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 boolean implementsStaticTypeCheck()
implementsStaticTypeCheck
in class Expression
public Expression staticTypeCheck(SequenceType req, boolean backwardsCompatible, RoleDiagnostic role, ExpressionVisitor visitor) throws XPathException
staticTypeCheck
in class Expression
req
- the required typebackwardsCompatible
- true if backwards compatibility mode appliesrole
- the role of the expression in relation to the required typevisitor
- an expression visitorXPathException
- if failures occur, for example if the static type of one branch of the conditional
is incompatible with the required typepublic Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) throws XPathException
Expression
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 Expression
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)public Expression copy(RebindingMap rebindings)
copy
in class Expression
rebindings
- public void checkForUpdatingSubexpressions() throws XPathException
checkForUpdatingSubexpressions
in class Expression
XPathException
- if the expression has a non-permitted updateing subexpressionpublic boolean isUpdatingExpression()
isUpdatingExpression
in class Expression
public boolean isVacuousExpression()
isVacuousExpression
in class Expression
public int getImplementationMethod()
getImplementationMethod
in class Instruction
Expression.ITERATE_METHOD
or Expression.EVALUATE_METHOD
or
Expression.PROCESS_METHOD
public int markTailFunctionCalls(StructuredQName qName, int arity)
markTailFunctionCalls
in class Expression
qName
- the name of the functionarity
- the arity (number of parameters) of the functionpublic ItemType getItemType()
getItemType
in class Instruction
public UType getStaticUType(UType contextItemType)
getStaticUType
in class Expression
contextItemType
- public int computeCardinality()
computeCardinality
in class Instruction
public int computeSpecialProperties()
computeSpecialProperties
in class Instruction
public final boolean mayCreateNewNodes()
mayCreateNewNodes
in class Instruction
public Expression unordered(boolean retainAllNodes, boolean forStreaming) throws XPathException
unordered
in class Expression
retainAllNodes
- set to true if the result must contain exactly the same nodes as the
original; set to false if the result can eliminate (or introduce) duplicates.forStreaming
- set to true if optimizing for streamingXPathException
- if the rewrite failspublic void checkPermittedContents(SchemaType parentType, boolean whole) throws XPathException
checkPermittedContents
in class Expression
parentType
- the "given complex type": the method is checking that the nodes returned by this
expression are acceptable members of the content model of this typewhole
- if true, we want to check that the value of this expression satisfies the content model
as a whole; if false we want to check that the value of the expression is acceptable as one part
of the contentXPathException
- if the value delivered by this expression cannot be part of the content model
of the given typepublic PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.
addToPathMap
in class Expression
pathMap
- the PathMap to which the expression should be addedpathMapNodeSet
- the set of PathMap nodes to which the paths from this expression should be appendedpublic java.lang.String toString()
toString
in class Expression
public java.lang.String toShortString()
Expression
toShortString
in class Expression
public void export(ExpressionPresenter out) throws XPathException
export
in interface ExportAgent
export
in class Expression
out
- the expression presenter used to display the structureXPathException
- if the export fails, for example if an expression is found that won't work
in the target environment.public TailCall processLeavingTail(XPathContext context) throws XPathException
processLeavingTail
in interface TailCallReturner
processLeavingTail
in class Instruction
context
- the dynamic context of this transformationXPathException
- if any non-recoverable dynamic error occurspublic Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
in class Instruction
context
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionpublic SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in class Instruction
context
- supplies the context for evaluationXPathException
- if any dynamic error occurs evaluating the
expressionpublic void evaluatePendingUpdates(XPathContext context, PendingUpdateList pul) throws XPathException
evaluatePendingUpdates
in class Expression
context
- the XPath dynamic evaluation contextpul
- the pending update list to which the results should be writtenXPathException
- if evaluation failspublic java.lang.String getExpressionName()
getExpressionName
in class Instruction
public java.lang.String getStreamerName()
Expression
getStreamerName
in class Expression
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