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Summary: Nested | Field | Method | Constr | Detail: Nested | Field | Method | Constr |
java.lang.Object
public class Copy
extends ElementCreator
Field Summary |
Fields inherited from class net.sf.saxon.instruct.ElementCreator | |
inheritNamespaces , preservingTypes |
Fields inherited from class net.sf.saxon.instruct.ParentNodeConstructor | |
content |
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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Item |
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void |
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int[] |
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int |
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ItemType |
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int |
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String |
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Expression |
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protected void |
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TailCall |
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Expression |
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Expression |
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Methods inherited from class net.sf.saxon.instruct.ElementCreator | |
checkContentSequence , computeSpecialProperties , evaluateItem , getActiveNamespaces , getImplementationMethod , getItemType , getNameCode , getNewBaseURI , isInheritNamespaces , isPreservingTypes , iterateEvents , outputNamespaceNodes , processLeavingTail , setValidationMode , suppressValidation |
Methods inherited from class net.sf.saxon.instruct.ParentNodeConstructor | |
addToPathMap , checkContentSequence , computeCardinality , createsNewNodes , getBaseURI , getCardinality , getContentExpression , getSchemaType , getValidationMode , isLazyConstruction , isNamespaceSensitive , iterateSubExpressions , optimize , promoteInst , replaceSubExpression , setBaseURI , setContentExpression , setLazyConstruction , setSchemaType , setValidationMode , simplify , typeCheck |
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 Copy(boolean copyNamespaces, boolean inheritNamespaces, SchemaType schemaType, int validation)
Create a shallow copy instruction
- Parameters:
copyNamespaces
- true if namespace nodes are to be copied when copying an elementinheritNamespaces
- true if child elements are to inherit the namespace nodes of their parentschemaType
- the Schema type against which the content is to be validatedvalidation
- the schema validation mode
public Expression copy()
Copy an expression. This makes a deep copy.
- Overrides:
- copy in interface Expression
- Returns:
- the copy of the original expression
public Item evaluateItem(XPathContext context) throws XPathException
Evaluate as an expression. We rely on the fact that when these instructions are generated by XQuery, there will always be a valueExpression to evaluate the content
- Specified by:
- evaluateItem in interface EvaluableItem
- Overrides:
- evaluateItem in interface ElementCreator
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[] getActiveNamespaces() throws XPathException
Callback to get a list of the intrinsic namespaces that need to be generated for the element. The result is an array of namespace codes, the codes either occupy the whole array or are terminated by a -1 entry. A result of null is equivalent to a zero-length array.
- Overrides:
- getActiveNamespaces in interface ElementCreator
public int getInstructionNameCode()
Get the name of this instruction for diagnostic and tracing purposes
- Overrides:
- getInstructionNameCode in interface Instruction
public ItemType getItemType(TypeHierarchy th)
Get the item type of the result of this instruction.
- Overrides:
- getItemType in interface ElementCreator
- Parameters:
th
- the type hierarchy cache
- Returns:
- The context item type.
public int getNameCode(XPathContext context) throws XPathException
Callback from ElementCreator when constructing an element
- Overrides:
- getNameCode in interface ElementCreator
- Parameters:
context
- XPath dynamic evaluation context
- Returns:
- the namecode of the element to be constructed
- Throws:
XPathException
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public String getNewBaseURI(XPathContext context)
Get the base URI of a copied element node (the base URI is retained in the new copy)
- Overrides:
- getNewBaseURI in interface ElementCreator
- Parameters:
context
- XPath dynamic evaluation context
- Returns:
- the base URI
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 ParentNodeConstructor
- 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)
protected void outputNamespaceNodes(XPathContext context, Receiver receiver) throws XPathException
Callback to output namespace nodes for the new element.
- Overrides:
- outputNamespaceNodes in interface ElementCreator
- Parameters:
context
- The execution contextreceiver
- the Receiver where the namespace nodes are to be written
- Throws:
XPathException
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public TailCall processLeavingTail(XPathContext context) throws XPathException
Evaluate the instruction to produce a new element node. This method is typically used when there is a parent element or document in a result tree, to which the new element is added.
- Specified by:
- processLeavingTail in interface TailCallReturner
- Overrides:
- processLeavingTail in interface ElementCreator
- Parameters:
context
- XPath dynamic evaluation context
- Returns:
- null (this instruction never returns a tail call)
- Throws:
XPathException
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public Expression simplify(ExpressionVisitor visitor) throws XPathException
Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression). The default implementation does nothing.
- Overrides:
- simplify in interface ParentNodeConstructor
- 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 ParentNodeConstructor
- 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)