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java.lang.Objectnet.sf.saxon.expr.ComputedExpression
net.sf.saxon.instruct.Instruction
net.sf.saxon.instruct.Block
Implements an imaginary xsl:block instruction which simply evaluates its contents. Used for top-level templates, xsl:otherwise, etc.
| Field Summary |
| Fields inherited from class net.sf.saxon.expr.ComputedExpression |
locationId, staticProperties |
| Fields inherited from interface net.sf.saxon.expr.Expression |
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD |
| Constructor Summary | |
Block()
|
|
| Method Summary | |
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. |
boolean |
createsNewNodes()
Determine whether this instruction creates new nodes. |
void |
display(int level,
java.io.PrintStream out,
Configuration config)
Diagnostic print of expression structure. |
static void |
displayChildren(Expression[] children,
int level,
Configuration config,
java.io.PrintStream out)
Display the children of an instruction for diagostics |
int |
getCardinality()
Determine the cardinality of the expression |
Expression[] |
getChildren()
Get the children of this instruction |
int |
getImplementationMethod()
An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). |
ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the items returned by this expression |
SequenceIterator |
iterate(XPathContext context)
Iterate over the results of all the child expressions |
java.util.Iterator |
iterateSubExpressions()
Get the immediate sub-expressions of this expression. |
static Expression |
makeBlock(Expression e1,
Expression e2)
|
Expression |
optimize(Optimizer opt,
StaticContext env,
ItemType 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 |
void |
setChildren(Expression[] children)
Set the children of this instruction |
Expression |
simplify(StaticContext env)
Simplify an expression. |
Expression |
typeCheck(StaticContext env,
ItemType contextItemType)
Perform type checking of an expression and its subexpressions. |
| Methods inherited from class net.sf.saxon.instruct.Instruction |
appendItem, assembleParams, assembleTunnelParams, computeCardinality, computeSpecialProperties, dynamicError, evaluateAsString, evaluateItem, getInstructionInfo, getInstructionNameCode, getSourceLocator, isXSLT, process, promote |
| Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Methods inherited from interface javax.xml.transform.SourceLocator |
getColumnNumber, getLineNumber, getPublicId, getSystemId |
| Constructor Detail |
public Block()
| Method Detail |
public static Expression makeBlock(Expression e1,
Expression e2)
public void setChildren(Expression[] children)
children - The instructions that are children of this instructionpublic Expression[] getChildren()
public java.util.Iterator iterateSubExpressions()
ComputedExpression
iterateSubExpressions in interface ExpressioniterateSubExpressions in class ComputedExpression
public boolean replaceSubExpression(Expression original,
Expression replacement)
replaceSubExpression in interface ContainerreplaceSubExpression in class ComputedExpressionoriginal - the original subexpressionreplacement - the replacement subexpression
public final ItemType getItemType(TypeHierarchy th)
getItemType in interface ExpressiongetItemType in class Instructionth -
public final int getCardinality()
getCardinality in interface ExpressiongetCardinality in class ComputedExpressionpublic final boolean createsNewNodes()
createsNewNodes in class Instruction
public Expression simplify(StaticContext env)
throws XPathException
simplify in interface Expressionsimplify in class InstructionXPathException - if an error is discovered during expression
rewriting
public Expression typeCheck(StaticContext env,
ItemType contextItemType)
throws XPathException
ExpressionThis 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.
env - the static context of the expressioncontextItemType - 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
public Expression optimize(Optimizer opt,
StaticContext env,
ItemType contextItemType)
throws XPathException
ExpressionThis 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.
opt - the optimizer in use. This provides access to supporting functions; it also allows
different optimization strategies to be used in different circumstances.env - the static context of the expressioncontextItemType - 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
protected void promoteInst(PromotionOffer offer)
throws XPathException
promoteInst in class Instructionoffer - The type of rewrite being offered
XPathException
public void checkPermittedContents(SchemaType parentType,
StaticContext env,
boolean whole)
throws XPathException
checkPermittedContents in interface ExpressioncheckPermittedContents in class ComputedExpressionXPathException
public void display(int level,
java.io.PrintStream out,
Configuration config)
level - indentation level for this expressionout - config -
public static void displayChildren(Expression[] children,
int level,
Configuration config,
java.io.PrintStream out)
public TailCall processLeavingTail(XPathContext context)
throws XPathException
Instruction
processLeavingTail in interface TailCallReturnerprocessLeavingTail in class Instructioncontext - The dynamic context of the transformation, giving access to the current node,
the current variables, etc.
XPathExceptionpublic int getImplementationMethod()
getImplementationMethod in interface ExpressiongetImplementationMethod in class Instruction
public SequenceIterator iterate(XPathContext context)
throws XPathException
iterate in interface Expressioniterate in class Instructioncontext - supplies the context for evaluation
XPathException - if any dynamic error occurs evaluating the
expression
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