Package com.icl.saxon.expr
Class SortedSelection
- java.lang.Object
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- com.icl.saxon.expr.Expression
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- com.icl.saxon.expr.NodeSetExpression
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- com.icl.saxon.expr.SortedSelection
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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.
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Field Summary
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Fields inherited from class com.icl.saxon.expr.Expression
staticContext
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Constructor Summary
Constructors Constructor Description SortedSelection(Expression s, int k)
Constructor
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
display(int level)
Diagnostic print of expression structureNodeEnumeration
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.void
setSortKey(SortKeyDefinition sk, int k)
Add a sort key and other sorting parametersExpression
simplify()
Simplify an expression-
Methods inherited from class com.icl.saxon.expr.NodeSetExpression
evaluate, evaluateAsBoolean, evaluateAsNodeSet, evaluateAsString, getDataType, outputStringValue, selectFirst
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Methods inherited from class com.icl.saxon.expr.Expression
containsReferences, evaluateAsNumber, getStaticContext, indent, isContextDocumentNodeSet, make, setStaticContext, usesCurrent
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Constructor Detail
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SortedSelection
public SortedSelection(Expression s, int k)
Constructor- Parameters:
s
- An expression whose value is the base nodeset to be sortedk
- the number of sort keys
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Method Detail
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setSortKey
public void setSortKey(SortKeyDefinition sk, int k)
Add a sort key and other sorting parameters- Parameters:
sk
- A SortKeyDefinitionk
- The index of this SortKeyDefinition. The first sort key in major-to-minor order is numbered 0 (zero), the others are 1, 2, ... in sequence.- Throws:
java.lang.ArrayIndexOutOfBoundsException
- if the sort key index is out of range, according to the number of sort keys defined when the SortedSelection was initialized.
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simplify
public Expression simplify() throws XPathException
Simplify an expression- Overrides:
simplify
in classExpression
- Returns:
- the simplified expression
- Throws:
XPathException
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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- Specified by:
getDependencies
in classExpression
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reduce
public Expression reduce(int dependencies, Context context) throws XPathException
Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.- Specified by:
reduce
in classExpression
- Parameters:
dependencies
- The dependencies to be removedcontext
- The context to be used for the partial evaluation- Returns:
- a new expression that does not have any of the specified dependencies
- Throws:
XPathException
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enumerate
public NodeEnumeration enumerate(Context context, boolean sort) throws XPathException
Evaluate the expression by sorting the base nodeset using the supplied key.- Specified by:
enumerate
in classNodeSetExpression
- Parameters:
context
- The context for the evaluationsort
- : must be false (because document order would be meaningless)- Returns:
- the sorted nodeset
- Throws:
XPathException
- when the expression does not return a nodeset.
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display
public void display(int level)
Diagnostic print of expression structure- Specified by:
display
in classExpression
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