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java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.instruct.Instruction
net.sf.saxon.instruct.ApplyImports
public class ApplyImports
extends Instruction
Field Summary |
Fields inherited from class net.sf.saxon.expr.Expression | |
EVALUATE_METHOD , ITERATE_METHOD , PROCESS_METHOD , locationId , staticProperties |
Constructor Summary | |
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Method Summary | |
Expression |
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boolean |
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void |
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int |
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Iterator |
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Expression |
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TailCall |
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protected void |
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boolean |
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void |
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Expression |
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Expression |
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Methods inherited from class net.sf.saxon.instruct.Instruction | |
assembleParams , assembleTunnelParams , computeCardinality , computeSpecialProperties , createsNewNodes , dynamicError , evaluateAsString , evaluateItem , getImplementationMethod , getInstructionInfo , getInstructionNameCode , getItemType , getSourceLocator , isXSLT , iterate , process , processLeavingTail , promote , promoteInst , simplify |
public Expression copy()
Copy an expression. This makes a deep copy.
- Overrides:
- copy in interface Expression
- Returns:
- the copy of the original expression
public final boolean createsNewNodes()
Determine whether this instruction creates new nodes. This implementation returns true (which is almost invariably the case, so it's not worth doing any further analysis to find out more precisely).
- Overrides:
- createsNewNodes in interface Instruction
public void explain(ExpressionPresenter out)
Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
- Overrides:
- explain in interface Expression
public int getInstructionNameCode()
Get the name of this instruction for diagnostic and tracing purposes
- Overrides:
- getInstructionNameCode in interface Instruction
public Iterator 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)
- Overrides:
- iterateSubExpressions in interface Expression
public Expression optimize(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
Perform optimisation of an expression and its subexpressions. This is the third and final phase of static optimization. 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.
- Overrides:
- optimize in interface Expression
- Parameters:
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 toType.ITEM_TYPE
- Returns:
- the original expression, rewritten if appropriate to optimize execution
- Throws:
XPathException
- if an error is discovered during this phase (typically a type error)
public TailCall processLeavingTail(XPathContext context) throws XPathException
ProcessLeavingTail: called to do the real work of this instruction. This method must be implemented in each subclass. The results of the instruction are written to the current Receiver, which can be obtained via the Controller.
- Specified by:
- processLeavingTail in interface TailCallReturner
- Overrides:
- processLeavingTail in interface Instruction
- Parameters:
context
- The dynamic context of the transformation, giving access to the current node, the current variables, etc.
- Returns:
- null if the instruction has completed execution; or a TailCall indicating a function call or template call that is delegated to the caller, to be made after the stack has been unwound so as to save stack space.
protected void promoteInst(PromotionOffer offer) throws XPathException
Handle promotion offers, that is, non-local tree rewrites.
- Overrides:
- promoteInst in interface Instruction
- Parameters:
offer
- The type of rewrite being offered
- Throws:
XPathException
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public boolean replaceSubExpression(Expression original, Expression replacement)
Replace one subexpression by a replacement subexpression
- Overrides:
- replaceSubExpression in interface Expression
- Parameters:
original
- the original subexpressionreplacement
- the replacement subexpression
- Returns:
- true if the original subexpression is found
public void setActualParameters(WithParam[] actualParams, WithParam[] tunnelParams)
Set the actual parameters on the call
public Expression simplify(ExpressionVisitor visitor) throws XPathException
Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression).
- Overrides:
- simplify in interface Instruction
- Parameters:
visitor
- an expression visitor
- Returns:
- the simplified expression
- Throws:
XPathException
- if an error is discovered during expression rewriting
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException
Perform type checking of an expression and its subexpressions. This is the second phase of static optimization. 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 parent pointer and 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.
- Overrides:
- typeCheck in interface Expression
- Parameters:
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 toType.ITEM_TYPE
- Returns:
- the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
- Throws:
XPathException
- if an error is discovered during this phase (typically a type error)