A SortKeyDefinition defines one component of a sort key.
Note that most attributes defining the sort key can be attribute value templates,
and can therefore vary from one invocation to another. We hold them as expressions. As
soon as they are all known (which in general is only at run-time), the SortKeyDefinition
is replaced by a FixedSortKeyDefinition in which all these values are fixed.
backwardsCompatible
protected boolean backwardsCompatible
baseURI
protected String baseURI
dataTypeExpression
protected Expression dataTypeExpression
emptyLeast
protected boolean emptyLeast
getBaseURI
public String getBaseURI()
Get the static base URI of the expression. This is needed to handle the case where a collation URI
evaluated at run-time turns out to be a relative URI.
- the static base URI of the expression
getCaseOrder
public Expression getCaseOrder()
Get the expression that defines the case order of the sort keys.
- the expression that defines the case order, whose run-time value will be "upper-first",
"lower-first", or "#default".
getCollation
public StringCollator getCollation()
Get the collation to be used
- A StringCollator, which encapsulates both the collation URI and the collating function
getCollationNameExpression
public Expression getCollationNameExpression()
Get the selected collation name
(specifically, an expression which when evaluated returns the collation URI).
- the expression that determines the collation name
getDataTypeExpression
public Expression getDataTypeExpression()
Get the expression that defines the data type of the sort keys
- the expression that defines the data type, as used in XSLT 1.0
getEmptyLeast
public boolean getEmptyLeast()
Ask whether empty sequence comes before other values or after them
- true if () is considered lower than any other value
getFinalComparator
public AtomicComparer getFinalComparator()
Get the comparator which is used to compare two values according to this sort key. This method
may be called either at compile time or at run-time. If no comparator has been allocated,
it returns null. It is then necessary to allocate a comparator using the
makeComparator(XPathContext)
method.
- the Atomic Comparer to be used
getLanguage
public Expression getLanguage()
Get the expression that defines the language of the sort keys
- exp the expression that determines the language
getOrder
public Expression getOrder()
Get the expression that defines the order as ascending or descending
- the expression that determines the order (always a literal in XQuery, but
can be defined by an AVT in XSLT)
getSortKey
public Expression getSortKey()
Get the expression used as the sort key
- the sort key select expression
getStable
public Expression getStable()
Ask whether this sort key definition is stable
- the expression that determines whether the sort key definition is stable
(it evaluates to the string "yes" or "no".
isBackwardsCompatible
public boolean isBackwardsCompatible()
Ask whether this sort key is evaluated in XSLT 1.0 backwards compatibility mode
- true if backwards compatibility mode was selected
isFixed
public boolean isFixed()
Ask whether the sort key definition is fixed, that is, whether all the information needed
to create a Comparator is known statically
- true if all information needed to create a Comparator is known statically
makeComparator
public AtomicComparer makeComparator(XPathContext context)
throws XPathException
Allocate an AtomicComparer to perform the comparisons described by this sort key component. This method
is called at run-time. The AtomicComparer takes into account not only the collation, but also parameters
such as order=descending and handling of empty sequence and NaN (the result of the compare()
method of the comparator is +1 if the second item is to sort after the first item)
context
- the dynamic evaluation context
- an AtomicComparer suitable for making the sort comparisons
setBackwardsCompatible
public void setBackwardsCompatible(boolean compatible)
Set whether this sort key is evaluated in XSLT 1.0 backwards compatibility mode
compatible
- true if backwards compatibility mode is selected
setBaseURI
public void setBaseURI(String baseURI)
Set the base URI of the expression. This is needed to handle the case where a collation URI
evaluated at run-time turns out to be a relative URI.
baseURI
- the static base URI of the expression
setCaseOrder
public void setCaseOrder(Expression exp)
Set the case order. This is supplied as an expression which must evaluate to "upper-first"
or "lower-first" or "#default". If the order is fixed, supply e.g. new StringValue("lower-first").
Default is "#default".
exp
- the expression that defines the case order
setCollation
public void setCollation(StringCollator collation)
Set the collation to be used
collation
- A StringCollator, which encapsulates both the collation URI and the collating function
setCollationNameExpression
public void setCollationNameExpression(Expression collationName)
Set the collation name (specifically, an expression which when evaluated returns the collation URI).
collationName
- the expression that determines the collation name
setDataTypeExpression
public void setDataTypeExpression(Expression exp)
Set the data type. This is supplied as an expression which must evaluate to "text",
"number", or a QName. If the data type is fixed, the valus should be supplied using
setDataType() and not via this method.
exp
- the expression that defines the data type, as used in XSLT 1.0
setEmptyLeast
public void setEmptyLeast(boolean emptyLeast)
Set whether empty sequence comes before other values or after them
emptyLeast
- true if () is considered lower than any other value
setFinalComparator
public void setFinalComparator(AtomicComparer comp)
Set the comparator which is used to compare two values according to this sort key. The comparator makes the final
decision whether one value sorts before or after another: this takes into account the data type, the collation,
whether empty comes first or last, whether the sort order is ascending or descending.
This method is called at compile time if all these factors are known at compile time.
It must not be called at run-time, except to reconstitute a finalComparator that has been
lost by virtue of serialization .
comp
- the Atomic Comparer to be used
setLanguage
public void setLanguage(Expression exp)
Set the language. This is supplied as an expression which evaluates to the language name.
If the order is fixed, supply e.g. new StringValue("de").
exp
- the expression that determines the language
setOrder
public void setOrder(Expression exp)
Set the order. This is supplied as an expression which must evaluate to "ascending"
or "descending". If the order is fixed, supply e.g. new StringValue("ascending").
Default is "ascending".
exp
- the expression that determines the order (always a literal in XQuery, but
can be defined by an AVT in XSLT)
setSortKey
public void setSortKey(Expression exp)
Set the expression used as the sort key
exp
- the sort key select expression
setStable
public void setStable(Expression stable)
Set whether this sort key definition is stable
stable
- the expression that determines whether the sort key definition is stable
(it evaluates to the string "yes" or "no".