public class Block extends Instruction
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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Block(Expression[] children)
Create a block, supplying its child expressions
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Modifier and Type | Method and Description |
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void |
checkForUpdatingSubexpressions()
Check to ensure that this expression does not contain any updating subexpressions.
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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.
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int |
computeSpecialProperties()
Get the static properties of this expression (other than its type).
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Expression |
copy(RebindingMap rebindings)
Copy an expression.
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void |
evaluatePendingUpdates(XPathContext context,
PendingUpdateList pul)
Evaluate an updating expression, adding the results to a Pending Update List.
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void |
export(ExpressionPresenter out)
Diagnostic print of expression structure.
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int |
getCardinality()
Determine the cardinality of the expression
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java.lang.String |
getExpressionName()
Get a name identifying the kind of expression, in terms meaningful to a user.
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int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
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ItemType |
getItemType()
Determine the data type of the items returned by this expression
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Operand[] |
getOperanda()
Get the children of this instruction
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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.
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java.lang.String |
getStreamerName()
Get the (partial) name of a class that supports streaming of this kind of expression
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boolean |
hasVariableBinding(Binding binding)
Ask whether this expression is, or contains, the binding of a given variable
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boolean |
isCandidateForSharedAppend()
Determine whether the block is a candidate for evaluation using a "shared append expression"
where the result of the evaluation is a sequence implemented as a list of subsequences
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boolean |
isInstruction()
Ask whether this expression is an instruction.
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boolean |
isVacuousExpression()
Determine whether this is a vacuous expression as defined in the XQuery update specification
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SequenceIterator |
iterate(XPathContext context)
Iterate over the results of all the child expressions
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static Expression |
makeBlock(Expression e1,
Expression e2)
Static factory method to create a block.
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static Expression |
makeBlock(java.util.List<Expression> list)
Static factory method to create a block from a list of expressions
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boolean |
mayCreateNewNodes()
Determine whether this instruction creates new nodes.
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static boolean |
mayReturnTypedNodes(Instruction insn,
TypeHierarchy th)
Determine whether the block includes any instructions that might return nodes with a type annotation
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Expression |
mergeAdjacentTextInstructions()
Merge any adjacent instructions that create literal text nodes
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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.
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Expression |
optimize(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Perform optimisation of an expression and its subexpressions.
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TailCall |
processLeavingTail(XPathContext context)
ProcessLeavingTail: called to do the real work of this instruction.
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Expression |
simplify()
Simplify an expression.
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java.lang.String |
toShortString()
Produce a short string identifying the expression for use in error messages
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Expression |
typeCheck(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Perform type checking of an expression and its subexpressions.
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alwaysCreatesNewNodes, assembleParams, assembleTunnelParams, computeCardinality, dynamicError, evaluateAsString, evaluateItem, getConstructType, getInstructionName, getInstructionNameCode, getNetCost, getSourceLocator, isXSLT, process, someOperandCreatesNewNodes
addToPathMap, adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, computeDependencies, computeHashCode, computeStaticProperties, dynamicError, effectiveBooleanValue, explain, getConfiguration, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, getIntrinsicDependencies, getLocalRetainedStaticContext, getLocation, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, hasCompatibleStaticContext, hashCode, identityHashCode, implementsStaticTypeCheck, isCallOn, isCallOnSystemFunction, isIdentical, isLiftable, isMultiThreaded, isSameExpression, isStaticPropertiesKnown, isSubtreeExpression, isUpdatingExpression, markTailFunctionCalls, operandList, operandSparseList, optimizeChildren, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplifyChildren, staticTypeCheck, suppressValidation, toPattern, toString, typeCheckChildren, typeError, unordered, verifyParentPointers, verifyParentPointers
public Block(Expression[] children)
children
- the child expressions in orderpublic boolean isInstruction()
Expression
isInstruction
in class Instruction
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 hasVariableBinding(Binding binding)
hasVariableBinding
in class Expression
binding
- the variable bindingpublic static Expression makeBlock(Expression e1, Expression e2)
e1
- the first subexpression (child) of the blocke2
- the second subexpression (child) of the blockpublic static Expression makeBlock(java.util.List<Expression> list)
list
- the list of expressions making up this block. The members of the List must
be instances of Expression. The list is effectively copied; subsequent changes
to the contents of the list have no effect.public java.lang.String getExpressionName()
Instruction
getExpressionName
in class Instruction
public Operand[] getOperanda()
public int computeSpecialProperties()
Instruction
computeSpecialProperties
in class Instruction
public static boolean mayReturnTypedNodes(Instruction insn, TypeHierarchy th)
insn
- the instruction (for example this block)th
- the type hierarchy cachepublic Expression mergeAdjacentTextInstructions()
public Expression copy(RebindingMap rebindings)
copy
in class Expression
rebindings
- public final ItemType getItemType()
getItemType
in class Instruction
public UType getStaticUType(UType contextItemType)
getStaticUType
in class Expression
contextItemType
- public final int getCardinality()
getCardinality
in class Expression
public final boolean mayCreateNewNodes()
mayCreateNewNodes
in class Instruction
public void checkForUpdatingSubexpressions() throws XPathException
checkForUpdatingSubexpressions
in class Expression
XPathException
- if the expression has a non-permitted updateing subexpressionpublic boolean isVacuousExpression()
isVacuousExpression
in class Expression
public Expression simplify() throws XPathException
simplify
in class Expression
XPathException
- if an error is discovered during expression
rewritingpublic boolean isCandidateForSharedAppend()
public 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 Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) 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 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 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 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 java.lang.String toShortString()
Expression
toShortString
in class Expression
public TailCall processLeavingTail(XPathContext context) throws XPathException
Instruction
processLeavingTail
in interface TailCallReturner
processLeavingTail
in class Instruction
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 int getImplementationMethod()
getImplementationMethod
in class Instruction
Expression.ITERATE_METHOD
or Expression.EVALUATE_METHOD
or
Expression.PROCESS_METHOD
public 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 getStreamerName()
Expression
getStreamerName
in class Expression
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