public class ByteCodeCandidate extends UnaryExpression implements TailCallReturner
Note, after the operand of the ByteCodeCandidate is compiled, the ByteCodeCandidate remains on the expression tree. We experimented with removing it from the tree, but run-time structural changes to the expression tree cause problems, for example when evaluating a closure which saves a reference to the tree.
Modifier and Type | Field and Description |
---|---|
int |
compiledMode |
static int |
GENERATED_COUNTER |
static long |
GENERATION_TIMER |
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 |
---|
ByteCodeCandidate(ExpressionOwner owner,
Expression child,
java.lang.String objectName,
int requiredEvaluationModes) |
Modifier and Type | Method and Description |
---|---|
Expression |
copy(RebindingMap rebindings)
Copy an expression.
|
boolean |
effectiveBooleanValue(XPathContext context)
Get the effective boolean value of the 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.
|
long |
getCountDown() |
java.lang.String |
getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user.
|
int |
getId() |
int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
|
protected OperandRole |
getOperandRole()
Get the usage (in terms of streamability analysis) of the single operand
|
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.
|
Expression |
optimize(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Perform optimisation of an expression and its subexpressions.
|
void |
process(XPathContext context)
Process the instruction, without returning any tail calls
|
TailCall |
processLeavingTail(XPathContext context)
ProcessLeavingTail: called to do the real work of this instruction.
|
void |
setByteCodeMonitor(ByteCodeMonitor monitor) |
void |
setCountDown(int val) |
computeCardinality, computeHashCode, computeSpecialProperties, displayOperator, equals, getBaseExpression, getItemType, getOperand, operands, setBaseExpression, toShortString, toString, typeCheck
addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, dynamicError, evaluateAsString, 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, getStaticUType, getStreamerName, hasCompatibleStaticContext, hashCode, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isCallOnSystemFunction, isIdentical, isInstruction, isLiftable, isMultiThreaded, isSameExpression, isStaticPropertiesKnown, isSubtreeExpression, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, typeCheckChildren, typeError, unordered, verifyParentPointers, verifyParentPointers
public static int GENERATED_COUNTER
public static long GENERATION_TIMER
public int compiledMode
public ByteCodeCandidate(ExpressionOwner owner, Expression child, java.lang.String objectName, int requiredEvaluationModes)
public int getId()
public void setCountDown(int val)
public long getCountDown()
protected OperandRole getOperandRole()
UnaryExpression
getOperandRole
in class UnaryExpression
public void setByteCodeMonitor(ByteCodeMonitor monitor)
public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
UnaryExpression
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 UnaryExpression
visitor
- an expression visitorcontextInfo
- 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 void export(ExpressionPresenter out) throws XPathException
UnaryExpression
export
in interface ExportAgent
export
in class UnaryExpression
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 boolean isVacuousExpression()
isVacuousExpression
in class Expression
public boolean isUpdatingExpression()
Expression
isUpdatingExpression
in class Expression
public void evaluatePendingUpdates(XPathContext context, PendingUpdateList pul) throws XPathException
Expression
evaluatePendingUpdates
in class Expression
context
- the XPath dynamic evaluation contextpul
- the pending update list to which the results should be writtenXPathException
- if evaluation failspublic int getImplementationMethod()
Expression
getImplementationMethod
in class Expression
Expression.ITERATE_METHOD
or Expression.EVALUATE_METHOD
or
Expression.PROCESS_METHOD
public Expression copy(RebindingMap rebindings)
Expression
copy
in class Expression
rebindings
- a mutable list of (old binding, new binding) pairs
that is used to update the bindings held in any
local variable references that are copied.public boolean effectiveBooleanValue(XPathContext context) throws XPathException
Expression
effectiveBooleanValue
in class Expression
context
- The context in which the expression is to be evaluatedXPathException
- if any dynamic error occurs evaluating the
expressionpublic void process(XPathContext context) throws XPathException
Expression
process
in class Expression
context
- The dynamic context, giving access to the current node,
the current variables, etc.XPathException
- if a dynamic error occurspublic TailCall processLeavingTail(XPathContext context) throws XPathException
TailCallReturner
processLeavingTail
in interface TailCallReturner
context
- The dynamic context of the transformation, giving access to the current node,
the current variables, etc.XPathException
- if a dynamic error occurs during the evaluation
of the instructionpublic Item 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 SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in class Expression
context
- supplies the context for evaluationXPathException
- if any dynamic error occurs evaluating the
expressionpublic java.lang.String getExpressionName()
Expression
getExpressionName
in class Expression
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