public class ContextItemExpression extends Expression
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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ContextItemExpression()
Create the expression
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Modifier and Type | Method and Description |
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PathMap.PathMapNodeSet |
addToPathMap(PathMap pathMap,
PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap.
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int |
computeCardinality()
Get the static cardinality
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int |
computeHashCode()
get HashCode for comparing two expressions
|
int |
computeSpecialProperties()
Determine the special properties of this expression
|
Expression |
copy(RebindingMap rebindings)
Create a clone copy of this expression
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boolean |
equals(java.lang.Object other)
Is this expression the same as another expression?
|
Item |
evaluateItem(XPathContext context)
Evaluate the expression
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void |
export(ExpressionPresenter destination)
Diagnostic print of expression structure.
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java.lang.String |
getErrorCodeForUndefinedContext() |
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().
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int |
getIntrinsicDependencies()
Determine the intrinsic dependencies of an expression, that is, those which are not derived
from the dependencies of its subexpressions.
|
ItemType |
getItemType()
Determine the item type
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int |
getNetCost()
Return the net cost of evaluating this expression, excluding the cost of evaluating
its operands.
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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 |
isContextPossiblyUndefined()
Ask whether the context item may possibly be undefined
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boolean |
isSubtreeExpression()
Determine whether the expression can be evaluated without reference to the part of the context
document outside the subtree rooted at the context node.
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SequenceIterator |
iterate(XPathContext context)
Iterate over the value of the expression
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Expression |
optimize(ExpressionVisitor visitor,
ContextItemStaticInfo contextItemType)
Perform optimisation of an expression and its subexpressions.
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void |
setErrorCodeForUndefinedContext(java.lang.String errorCode) |
void |
setStaticInfo(ContextItemStaticInfo info)
Set static information about the context item
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Pattern |
toPattern(Configuration config,
boolean is30)
Convert this expression to an equivalent XSLT pattern
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java.lang.String |
toShortString()
Produce a short string identifying the expression for use in error messages
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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.
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Expression |
typeCheck(ExpressionVisitor visitor,
ContextItemStaticInfo contextInfo)
Type-check the expression.
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adoptChildExpression, allowExtractingCommonSubexpressions, checkedOperands, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, evaluatePendingUpdates, explain, getCardinality, getConfiguration, getConstructType, getCost, getDependencies, getEvaluationMethod, getExtraProperty, getIntegerBounds, getInterpretedExpression, getLocalRetainedStaticContext, getLocation, getObjectName, getPackageData, getParentExpression, getProperties, getProperty, getRetainedStaticContext, getScopingExpression, getSlotsUsed, getSpecialProperties, getStaticBaseURI, getStaticBaseURIString, getStaticType, hasCompatibleStaticContext, hashCode, hasVariableBinding, identityHashCode, implementsStaticTypeCheck, isCallOn, isCallOnSystemFunction, isIdentical, isInstruction, isLiftable, isMultiThreaded, isSameExpression, isStaticPropertiesKnown, isUpdatingExpression, isVacuousExpression, markTailFunctionCalls, operandList, operands, operandSparseList, optimizeChildren, process, resetLocalStaticProperties, restoreParentPointers, setEvaluationMethod, setExtraProperty, setFiltered, setFlattened, setLocation, setParentExpression, setRetainedStaticContext, setRetainedStaticContextLocally, setRetainedStaticContextThoroughly, setStaticProperty, simplify, simplifyChildren, staticTypeCheck, suppressValidation, typeCheckChildren, typeError, unordered, verifyParentPointers, verifyParentPointers
public java.lang.String getExpressionName()
getExpressionName
in class Expression
public Expression copy(RebindingMap rebindings)
copy
in class Expression
rebindings
- public void setErrorCodeForUndefinedContext(java.lang.String errorCode)
public java.lang.String getErrorCodeForUndefinedContext()
public void setStaticInfo(ContextItemStaticInfo info)
info
- static information about the context itempublic Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) throws XPathException
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 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 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 ItemType getItemType()
getItemType
in class Expression
public UType getStaticUType(UType contextItemType)
getStaticUType
in class Expression
contextItemType
- the static type of the context itempublic boolean isContextPossiblyUndefined()
public int computeCardinality()
computeCardinality
in class Expression
StaticProperty.ALLOWS_ZERO_OR_ONE
,
StaticProperty.EXACTLY_ONE
, StaticProperty.ALLOWS_ONE_OR_MORE
,
StaticProperty.ALLOWS_ZERO_OR_MORE
public int computeSpecialProperties()
computeSpecialProperties
in class Expression
StaticProperty.NON_CREATIVE
public int getImplementationMethod()
Expression
getImplementationMethod
in class Expression
Expression.ITERATE_METHOD
or Expression.EVALUATE_METHOD
or
Expression.PROCESS_METHOD
public boolean equals(java.lang.Object other)
equals
in class java.lang.Object
public int computeHashCode()
computeHashCode
in class Expression
public int getIntrinsicDependencies()
Expression
getIntrinsicDependencies
in class Expression
public 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 PathMapNodeSet to which the paths embodied in this expression should be addedpublic boolean isSubtreeExpression()
isSubtreeExpression
in class Expression
public int getNetCost()
Expression
getNetCost
in class Expression
public Pattern toPattern(Configuration config, boolean is30) throws XPathException
toPattern
in class Expression
config
- the Saxon configurationis30
- true if this is XSLT 3.0XPathException
- if conversion is not possiblepublic java.lang.String getStreamerName()
getStreamerName
in class Expression
public SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in class Expression
context
- supplies the context for evaluationXPathException
- if any dynamic error occurs evaluating the
expressionpublic 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 java.lang.String toString()
toString
in class Expression
public void export(ExpressionPresenter destination) throws XPathException
export
in interface ExportAgent
export
in class Expression
destination
- 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
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