Class SortKeyDefinition

java.lang.Object
net.sf.saxon.sort.SortKeyDefinition
All Implemented Interfaces:
Serializable

public class SortKeyDefinition extends Object implements Serializable
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.
See Also:
  • Field Details

    • sortKey

      protected Expression sortKey
    • order

      protected Expression order
    • dataTypeExpression

      protected Expression dataTypeExpression
    • caseOrder

      protected Expression caseOrder
    • language

      protected Expression language
    • collationName

      protected Expression collationName
    • stable

      protected Expression stable
    • collation

      protected StringCollator collation
    • baseURI

      protected String baseURI
    • emptyLeast

      protected boolean emptyLeast
    • backwardsCompatible

      protected boolean backwardsCompatible
  • Constructor Details

    • SortKeyDefinition

      public SortKeyDefinition()
  • Method Details

    • setSortKey

      public void setSortKey(Expression exp)
      Set the expression used as the sort key
      Parameters:
      exp - the sort key select expression
    • getSortKey

      public Expression getSortKey()
      Get the expression used as the sort key
      Returns:
      the sort key select expression
    • 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".
      Parameters:
      exp - the expression that determines the order (always a literal in XQuery, but can be defined by an AVT in XSLT)
    • getOrder

      public Expression getOrder()
      Get the expression that defines the order as ascending or descending
      Returns:
      the expression that determines the order (always a literal in XQuery, but can be defined by an AVT in XSLT)
    • 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.
      Parameters:
      exp - the expression that defines the data type, as used in XSLT 1.0
    • getDataTypeExpression

      public Expression getDataTypeExpression()
      Get the expression that defines the data type of the sort keys
      Returns:
      the expression that defines the data type, as used in XSLT 1.0
    • 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".
      Parameters:
      exp - the expression that defines the case order
    • getCaseOrder

      public Expression getCaseOrder()
      Get the expression that defines the case order of the sort keys.
      Returns:
      the expression that defines the case order, whose run-time value will be "upper-first", "lower-first", or "#default".
    • 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").
      Parameters:
      exp - the expression that determines the language
    • getLanguage

      public Expression getLanguage()
      Get the expression that defines the language of the sort keys
      Returns:
      exp the expression that determines the language
    • setCollationNameExpression

      public void setCollationNameExpression(Expression collationName)
      Set the collation name (specifically, an expression which when evaluated returns the collation URI).
      Parameters:
      collationName - the expression that determines the collation name
    • getCollationNameExpression

      public Expression getCollationNameExpression()
      Get the selected collation name (specifically, an expression which when evaluated returns the collation URI).
      Returns:
      the expression that determines the collation name
    • setCollation

      public void setCollation(StringCollator collation)
      Set the collation to be used
      Parameters:
      collation - A StringCollator, which encapsulates both the collation URI and the collating function
    • getCollation

      public StringCollator getCollation()
      Get the collation to be used
      Returns:
      A StringCollator, which encapsulates both the collation URI and the collating function
    • 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.
      Parameters:
      baseURI - the static base URI of the expression
    • 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.
      Returns:
      the static base URI of the expression
    • setStable

      public void setStable(Expression stable)
      Set whether this sort key definition is stable
      Parameters:
      stable - the expression that determines whether the sort key definition is stable (it evaluates to the string "yes" or "no".
    • getStable

      public Expression getStable()
      Ask whether this sort key definition is stable
      Returns:
      the expression that determines whether the sort key definition is stable (it evaluates to the string "yes" or "no".
    • setBackwardsCompatible

      public void setBackwardsCompatible(boolean compatible)
      Set whether this sort key is evaluated in XSLT 1.0 backwards compatibility mode
      Parameters:
      compatible - true if backwards compatibility mode is selected
    • isBackwardsCompatible

      public boolean isBackwardsCompatible()
      Ask whether this sort key is evaluated in XSLT 1.0 backwards compatibility mode
      Returns:
      true if backwards compatibility mode was selected
    • setEmptyLeast

      public void setEmptyLeast(boolean emptyLeast)
      Set whether empty sequence comes before other values or after them
      Parameters:
      emptyLeast - true if () is considered lower than any other value
    • getEmptyLeast

      public boolean getEmptyLeast()
      Ask whether empty sequence comes before other values or after them
      Returns:
      true if () is considered lower than any other value
    • 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
      Returns:
      true if all information needed to create a Comparator is known statically
    • simplify

      public SortKeyDefinition simplify(ExpressionVisitor visitor) throws XPathException
      Simplify this sort key definition
      Parameters:
      visitor - the expression visitor
      Returns:
      the simplified sort key definition
      Throws:
      XPathException - if any failure occurs
    • 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)
      Parameters:
      context - the dynamic evaluation context
      Returns:
      an AtomicComparer suitable for making the sort comparisons
      Throws:
      XPathException
    • 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 .

      Parameters:
      comp - the Atomic Comparer to be used
    • 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(net.sf.saxon.expr.XPathContext) method.
      Returns:
      the Atomic Comparer to be used