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java.lang.Object net.sf.saxon.expr.Expression net.sf.saxon.expr.instruct.Instruction com.saxonica.xsltextn.MergeInstr
public class MergeInstr
Nested Class Summary | |
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static class |
MergeInstr.ItemWithMergeKeys
Inner class representing an item together with its merge keys, suitable for encapsulation as an ObjectValue. |
static class |
MergeInstr.MergeSource
Inner class representing one merge source |
Field Summary | |
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protected Expression |
action
|
protected AtomicComparer[] |
comparators
|
protected MergeInstr.MergeSource[] |
mergeSources
|
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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MergeInstr(MergeInstr.MergeSource[] mSources,
Expression action)
Create the merge instruction |
Method Summary | |
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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. |
Expression |
copy()
Copy an expression. |
boolean |
createsNewNodes()
Determine whether this instruction creates new nodes. |
void |
explain(ExpressionPresenter out)
Diagnostic print of expression structure. |
Expression |
getAction()
|
ItemOrderComparer |
getComparer(SortKeyDefinition[] sKeys,
AtomicComparer[] comps)
|
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 namecode of the instruction for use in diagnostics |
ItemType |
getItemType(TypeHierarchy th)
Get the item type of the items returned by evaluating this instruction |
MergeInstr.MergeSource[] |
getMergeSourceExpr()
|
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) |
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. |
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, computeSpecialProperties, dynamicError, evaluateAsString, evaluateItem, getConstructType, getExpressionName, getImplementationMethod, getInstructionName, getIteratorFromProcessMethod, getSourceLocator, isXSLT, process, promote, promoteInst |
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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protected MergeInstr.MergeSource[] mergeSources
protected Expression action
protected AtomicComparer[] comparators
Constructor Detail |
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public MergeInstr(MergeInstr.MergeSource[] mSources, Expression action)
mSources
- the set of merge source definitionsaction
- the action to be performed on each group of items with identical merge keysMethod Detail |
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public MergeInstr.MergeSource[] getMergeSourceExpr()
public Expression getAction()
public int getInstructionNameCode()
getInstructionNameCode
in class Instruction
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 ItemType getItemType(TypeHierarchy th)
getItemType
in class Instruction
th
- the type hierarchy cache
public 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 boolean hasLoopingSubexpression(Expression child)
hasLoopingSubexpression
in class Expression
child
- the immediate subexpression
public final boolean createsNewNodes()
createsNewNodes
in class Instruction
public boolean replaceSubExpression(Expression original, Expression replacement)
replaceSubExpression
in class Expression
original
- the original subexpressionreplacement
- the replacement subexpression
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 SequenceIterator iterate(XPathContext context) throws XPathException
Instruction
iterate
in class Instruction
context
- supplies the context for evaluation
XPathException
- if any dynamic error occurs evaluating the
expressionpublic Iterator<Expression> iterateSubExpressions()
iterateSubExpressions
in class Expression
public Iterator<Expression> iterateSameFocusSubExpressions()
iterateSameFocusSubExpressions
in class Expression
public Expression getGroupingKey()
public ItemOrderComparer getComparer(SortKeyDefinition[] sKeys, AtomicComparer[] comps)
public Expression simplify(ExpressionVisitor visitor) throws XPathException
simplify
in class Instruction
visitor
- expression visitor object
XPathException
- if an error is discovered during expression
rewritingpublic Expression copy()
copy
in class Expression
public void explain(ExpressionPresenter out)
explain
in class Expression
out
- the expression presenter used to display the structurepublic 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 instruction
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