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java.lang.Object net.sf.saxon.expr.Expression net.sf.saxon.expr.instruct.Instruction net.sf.saxon.expr.instruct.ForEachGroup
public class ForEachGroup
Handler for xsl:for-each-group elements in stylesheet. This is a new instruction defined in XSLT 2.0
Field Summary | |
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static int |
GROUP_ADJACENT
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static int |
GROUP_BY
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static int |
GROUP_ENDING
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static int |
GROUP_STARTING
|
Fields inherited from class net.sf.saxon.expr.Expression |
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EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD |
Constructor Summary | |
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ForEachGroup(Expression select,
Expression action,
byte algorithm,
Expression key,
StringCollator collator,
Expression collationNameExpression,
URI baseURI,
SortKeyDefinition[] sortKeys)
Create a for-each-group instruction |
Method Summary | |
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PathMap.PathMapNodeSet |
addToPathMap(PathMap pathMap,
PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap. |
void |
checkPermittedContents(SchemaType parentType,
StaticContext env,
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 |
computeDependencies()
Compute the dependencies of an expression, as the union of the dependencies of its subexpressions. |
int |
computeSpecialProperties()
Get the static properties of this expression (other than its type). |
Expression |
copy()
Copy an expression. |
boolean |
createsNewNodes()
Determine whether this instruction creates new nodes. |
AtomicValue |
evaluateSortKey(int n,
XPathContext c)
Callback for evaluating the sort keys |
void |
explain(ExpressionPresenter out)
Diagnostic print of expression structure. |
Expression |
getActionExpression()
Get the action expression (the content of the for-each-group) |
byte |
getAlgorithm()
Get the grouping algorithm (one of group-by, group-adjacent, group-starting-with, group-ending-with) |
URI |
getBaseURI()
Get the static base URI of the instruction |
StringCollator |
getCollation()
Get the statically-determined collator, or null if the collation was not determined statically |
Expression |
getCollationNameExpression()
Get the expression which, on evaluation, yields the name of the collation to be used |
Expression |
getGroupingKey()
Get the grouping key expression expression (the group-by or group-adjacent expression, or a PatternSponsor containing the group-starting-with or group-ending-with expression) |
int |
getInstructionNameCode()
Get the name of this instruction for diagnostic and tracing purposes |
ItemType |
getItemType(TypeHierarchy th)
Get the item type of the items returned by evaluating this instruction |
Expression |
getSelectExpression()
Get the select expression |
AtomicComparer[] |
getSortKeyComparators()
Get the statically-allocated sort key comparators for sorting at the group level, if known |
SortKeyDefinition[] |
getSortKeyDefinitions()
Get the sort keys defined at the for-each-group level, that is, the keys for sorting the groups |
boolean |
hasLoopingSubexpression(Expression child)
Given an expression that is an immediate child of this expression, test whether the evaluation of the parent expression causes the child expression to be evaluated repeatedly |
SequenceIterator |
iterate(XPathContext context)
Return an Iterator to iterate over the values of a sequence. |
Iterator<Expression> |
iterateSameFocusSubExpressions()
Get the immediate sub-expressions of this expression that are evaluated with the same focus (context item, position, and size) as the parent expression. |
Iterator<Expression> |
iterateSubExpressions()
Get all the XPath expressions associated with this instruction (in XSLT terms, the expression present on attributes of the instruction, as distinct from the child instructions in a sequence construction) |
SequenceIterator |
map(XPathContext context)
Map one item to a sequence. |
Expression |
optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Perform optimisation of an expression and its subexpressions. |
TailCall |
processLeavingTail(XPathContext context)
ProcessLeavingTail: called to do the real work of this instruction. |
protected void |
promoteInst(PromotionOffer offer)
Handle promotion offers, that is, non-local tree rewrites. |
boolean |
replaceSubExpression(Expression original,
Expression replacement)
Replace one subexpression by a replacement subexpression |
Expression |
simplify(ExpressionVisitor visitor)
Simplify an expression. |
Expression |
typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Perform type checking of an expression and its subexpressions. |
Methods inherited from class net.sf.saxon.expr.instruct.Instruction |
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assembleParams, assembleTunnelParams, computeCardinality, dynamicError, evaluateAsString, evaluateItem, getConstructType, getExpressionName, getImplementationMethod, getInstructionName, getIteratorFromProcessMethod, getSourceLocator, isXSLT, process, promote |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Methods inherited from interface javax.xml.transform.SourceLocator |
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getColumnNumber, getLineNumber, getPublicId, getSystemId |
Field Detail |
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public static final int GROUP_BY
public static final int GROUP_ADJACENT
public static final int GROUP_STARTING
public static final int GROUP_ENDING
Constructor Detail |
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public ForEachGroup(Expression select, Expression action, byte algorithm, Expression key, StringCollator collator, Expression collationNameExpression, URI baseURI, SortKeyDefinition[] sortKeys)
select
- the select expression (selects the population to be grouped)action
- the body of the for-each-group (applied to each group in turn)algorithm
- one of group-by, group-adjacent, group-starting-with, group-ending-withkey
- expression to evaluate the grouping keycollator
- user for comparing stringscollationNameExpression
- expression that yields the name of the collation to be usedbaseURI
- static base URI of the expressionsortKeys
- list of xsl:sort keys for sorting the groupsMethod Detail |
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public int getInstructionNameCode()
getInstructionNameCode
in class Instruction
public Expression getSelectExpression()
public Expression getActionExpression()
public byte getAlgorithm()
public Expression getGroupingKey()
public SortKeyDefinition[] getSortKeyDefinitions()
public AtomicComparer[] getSortKeyComparators()
public StringCollator getCollation()
public URI getBaseURI()
public Expression simplify(ExpressionVisitor visitor) throws XPathException
simplify
in class Instruction
visitor
- an expression visitor
XPathException
- if an error is discovered during expression
rewritingpublic Expression typeCheck(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType contextItemType) 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.
If the implementation returns a value other than "this", then it is required to ensure that the location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.
typeCheck
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 optimize(ExpressionVisitor visitor, ExpressionVisitor.ContextItemType 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()
copy
in class Expression
public ItemType getItemType(TypeHierarchy th)
getItemType
in class Instruction
th
- the type hierarchy cache
public int computeDependencies()
computeDependencies
in class Expression
public int computeSpecialProperties()
computeSpecialProperties
in class Instruction
public final boolean createsNewNodes()
createsNewNodes
in class Instruction
protected void promoteInst(PromotionOffer offer) throws XPathException
promoteInst
in class Instruction
offer
- The type of rewrite being offered
XPathException
public Iterator<Expression> iterateSubExpressions()
iterateSubExpressions
in class Expression
public Iterator<Expression> iterateSameFocusSubExpressions()
iterateSameFocusSubExpressions
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 set of nodes within the path map
public boolean hasLoopingSubexpression(Expression child)
hasLoopingSubexpression
in class Expression
child
- the immediate subexpression
public boolean replaceSubExpression(Expression original, Expression replacement)
replaceSubExpression
in class Expression
original
- the original subexpressionreplacement
- the replacement subexpression
public void checkPermittedContents(SchemaType parentType, StaticContext env, 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 typeenv
- the static contextwhole
- 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 content
XPathException
- if the value delivered by this expression cannot be part of the content model
of the given typepublic 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 Expression getCollationNameExpression()
public SequenceIterator iterate(XPathContext context) throws XPathException
iterate
in class Instruction
context
- supplies the context for evaluation
XPathException
- if any dynamic error occurs evaluating the
expressionpublic SequenceIterator map(XPathContext context) throws XPathException
map
in interface ContextMappingFunction
context
- The processing context. This is supplied only for mapping constructs that
set the context node, position, and size. Otherwise it is null.
XPathException
- if a dynamic error is detectedpublic AtomicValue evaluateSortKey(int n, XPathContext c) throws XPathException
evaluateSortKey
in interface SortKeyEvaluator
XPathException
public void explain(ExpressionPresenter out)
explain
in class Expression
out
- the expression presenter used to display the structure
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