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java.lang.Object net.sf.saxon.expr.parser.PromotionOffer
public class PromotionOffer
PromotionOffer is an object used transiently during compilation of an expression. It contains information passed by a containing expression to its subexpressions, when looking for subexpressions that can be promoted to a higher level because they are not dependent on the context established by the containing expression. The object is also used to pass back return information when the promotion actually takes place.
Field Summary | |
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boolean |
accepted
Flag that is set if the offer has been accepted, that is, if the expression has changed |
int |
action
action is one of the possible promotion actions, FOCUS_INDEPENDENT, RANGE_INDEPENDENT, INLINE_VARIABLE_REFERENCES, UNORDERED, EXTRACT_GLOBAL_VARIABLES |
Binding[] |
bindingList
In the case of RANGE_INDEPENDENT, "binding" identifies the range variables whose dependencies we are looking for. |
Expression |
containingExpression
When a promotion offer is made, containingExpression identifies the level to which the promotion should occur. |
static int |
EXTRACT_GLOBAL_VARIABLES
EXTRACT_GLOBAL_VARIABLES identifies subexpressions that are not constant, but have no dependencies other than on global variables or parameters (they must also be non-creative). |
static int |
FOCUS_INDEPENDENT
FOCUS_INDEPENDENT requests promotion of all non-trivial subexpressions that don't depend on the focus. |
static int |
INLINE_VARIABLE_REFERENCES
Inline variable references causes all references to a variable V to be replaced by the expression E. |
boolean |
promoteDocumentDependent
In the case of FOCUS_INDEPENDENT, "promoteDocumentDependent" is a boolean that, when set to true, indicates that it is safe to promote a subexpression that depends on the context document but not on other aspects of the focus. |
boolean |
promoteXSLTFunctions
In the case of FOCUS_INDEPENDENT, "promoteXSLTFunctions" is a boolean that, when set to true, indicates that it is safe to promote XSLT functions such as current(). |
static int |
RANGE_INDEPENDENT
RANGE_INDEPENDENT requests promotion of all non-trivial subexpressions that don't depend on a specified range variable. |
static int |
REPLACE_CURRENT
REPLACE_CURRENT causes calls to the XSLT current() function to be replaced by reference to a variable. |
boolean |
retainAllNodes
In the case of UNORDERED, "retainAllNodes" is a boolean that is set to true if the nodes can be delivered in any order so long as the right number of nodes are delivered. |
static int |
UNORDERED
UNORDERED indicates that the containing expression does not require the results to be delivered in any particular order. |
ExpressionVisitor |
visitor
The expression visitor in use |
Constructor Summary | |
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PromotionOffer(Optimizer optimizer)
Create a PromotionOffer for use with a particular Optimizer |
Method Summary | |
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Expression |
accept(Expression parent,
Expression child)
Method to test whether a subexpression qualifies for promotion, and if so, to accept the promotion. |
Optimizer |
getOptimizer()
Get the optimizer in use |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
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public static final int FOCUS_INDEPENDENT
public static final int RANGE_INDEPENDENT
public static final int INLINE_VARIABLE_REFERENCES
public static final int UNORDERED
public static final int REPLACE_CURRENT
public static final int EXTRACT_GLOBAL_VARIABLES
public ExpressionVisitor visitor
public int action
public boolean promoteDocumentDependent
public boolean promoteXSLTFunctions
public boolean retainAllNodes
public Binding[] bindingList
public Expression containingExpression
public boolean accepted
Constructor Detail |
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public PromotionOffer(Optimizer optimizer)
optimizer
- the optimizerMethod Detail |
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public Optimizer getOptimizer()
public Expression accept(Expression parent, Expression child) throws XPathException
parent
- child
- the subexpression in question
XPathException
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