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java.lang.Object | +--net.sf.saxon.expr.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 | |
int |
action
action is one of the possible promotion actions, FOCUS_INDEPENDENT, RANGE_INDEPENDENT, INLINE_VARIABLE_REFERENCES, ANY_ORDER, ANY_ORDER_UNIQUE |
Binding |
binding
In the case of RANGE_INDEPENDENT, "binding" identifies the range variable 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 |
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 |
mustEliminateDuplicates
In the case of UNORDERED, "mustEliminateDuplicates" is a boolean that is set to true if the nodes can be delivered in any order so long as there are no duplicates (for example, as required by the count() function). |
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. |
static int |
RANGE_INDEPENDENT
RANGE_INDEPENDENT requests promotion of all non-trivial subexpressions that don't depend on a specified range variable. |
static int |
UNORDERED
UNORDERED indicates that the containing expression does not require the results to be delivered in any particular order. |
Constructor Summary | |
PromotionOffer()
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Method Summary | |
Expression |
accept(Expression child)
Method to test whether a subexpression qualifies for promotion, and if so, to accept the promotion. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
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 int action
public boolean promoteDocumentDependent
public boolean mustEliminateDuplicates
public Binding binding
public Expression containingExpression
Constructor Detail |
public PromotionOffer()
Method Detail |
public Expression accept(Expression child) throws XPathException
XPathException
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