com.icl.saxon.expr
Class SortedSelection

java.lang.Object
  |
  +--com.icl.saxon.expr.Expression
        |
        +--com.icl.saxon.expr.NodeSetExpression
              |
              +--com.icl.saxon.expr.SortedSelection

public class SortedSelection
extends NodeSetExpression

A NodeSetExpression that retrieves nodes in order according to a specified sort key.
Note there is no direct XSL expression syntax that generates this.
The expression sorts a base NodeSet according to the value of a specified sort key. The sort key may be composite. The base NodeSet will always be in document order.


Fields inherited from class com.icl.saxon.expr.Expression
staticContext
 
Constructor Summary
SortedSelection(Expression s)
          Constructor
 
Method Summary
 void addSortKey(SortKeyDefinition sk)
          Add a sort key and other sorting parameters
 NodeEnumeration enumerate(Context context, boolean sort)
          Evaluate the expression by sorting the base nodeset using the supplied key.
 int getDependencies()
          Determine which aspects of the context the expression depends on.
 Expression reduce(int dependencies, Context context)
          Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
 Expression simplify()
          Simplify an expression
 
Methods inherited from class com.icl.saxon.expr.NodeSetExpression
evaluate, evaluateAsBoolean, evaluateAsNodeSet, evaluateAsString, getDataType, outputStringValue, selectFirst
 
Methods inherited from class com.icl.saxon.expr.Expression
containsReferences, evaluateAsNumber, getStaticContext, make, setStaticContext, usesCurrent
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

SortedSelection

public SortedSelection(Expression s)
Constructor
Parameters:
s - the base nodeset to be sorted
Method Detail

addSortKey

public void addSortKey(SortKeyDefinition sk)
Add a sort key and other sorting parameters
Parameters:
sk - A SortKeyDefinition

simplify

public Expression simplify()
                    throws org.xml.sax.SAXException
Simplify an expression
Overrides:
simplify in class Expression
Returns:
the simplified expression

getDependencies

public int getDependencies()
Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as Context.VARIABLES and Context.CURRENT_NODE
Overrides:
getDependencies in class Expression

reduce

public Expression reduce(int dependencies,
                         Context context)
                  throws org.xml.sax.SAXException
Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
Overrides:
reduce in class Expression
Parameters:
dependencies - The dependencies to be removed
context - The context to be used for the partial evaluation
Returns:
a new expression that does not have any of the specified dependencies

enumerate

public NodeEnumeration enumerate(Context context,
                                 boolean sort)
                          throws org.xml.sax.SAXException
Evaluate the expression by sorting the base nodeset using the supplied key.
Overrides:
enumerate in class NodeSetExpression
Parameters:
context - The context for the evaluation
sort: - must be false (because document order would be meaningless)
Returns:
the sorted nodeset