ConditionalSorter

java.lang.Object
- net.sf.saxon.expr.Expression
- - net.sf.saxon.sort.ConditionalSorter

All Implemented Interfaces:

java.io.Serializable, javax.xml.transform.SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, InstructionInfo, org.xml.sax.Locator
```
public class ConditionalSorter
extends Expression
```
An expression that sorts an underlying sequence into document order if some condition is true, or that returns the sequence "as is" (knowing that it doesn't need sorting) if the condition is false.

See Also:

Serialized Form

Field Summary
- Fields inherited from class net.sf.saxon.expr.Expression
  EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties

Constructor Summary

Constructors
Constructor Description

ConditionalSorter(Expression condition, DocumentSorter sorter)
Create a conditional document sorter

Constructors
Constructor	Description
`ConditionalSorter(Expression condition, DocumentSorter sorter)`	Create a conditional document sorter

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected int`	`computeCardinality()`	Compute the static cardinality of this expression
`protected int`	`computeSpecialProperties()`	Compute the special properties of this expression.
`Expression`	`copy()`	Copy an expression.
`void`	`explain(ExpressionPresenter out)`	Diagnostic print of expression structure.
`int`	`getCardinality()`	Determine the static cardinality of the expression.
`Expression`	`getCondition()`	Get the condition under which the nodes need to be sorted
`DocumentSorter`	`getDocumentSorter()`	Get the document sorter, which sorts the nodes if the condition is true
`int`	`getImplementationMethod()`	An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process().
`ItemType`	`getItemType(TypeHierarchy th)`	Determine the data type of the expression, if possible.
`SequenceIterator`	`iterate(XPathContext context)`	Return an Iterator to iterate over the values of a sequence.
`java.util.Iterator`	`iterateSubExpressions()`	Get the immediate sub-expressions of this expression.
`Expression`	`promote(PromotionOffer offer)`	Offer promotion for this subexpression.
`boolean`	`replaceSubExpression(Expression original, Expression replacement)`	Replace one subexpression by a replacement subexpression

Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, findParentOf, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterateEvents, markTailFunctionCalls, optimize, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, simplify, staticTypeCheck, suppressValidation, toString, typeCheck, typeError

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - ConditionalSorter
```
public ConditionalSorter(Expression condition,
                         DocumentSorter sorter)
```
    Create a conditional document sorter
    
    Parameters:
    
    condition - the conditional expression
    
    sorter - the sorting expression
- Method Detail
  - getCondition
```
public Expression getCondition()
```
    Get the condition under which the nodes need to be sorted
    
    Returns:
    
    the condition (an expression)
  - getDocumentSorter
```
public DocumentSorter getDocumentSorter()
```
    Get the document sorter, which sorts the nodes if the condition is true
    
    Returns:
    
    the document sorter
  - getCardinality
```
public int getCardinality()
```
    Determine the static cardinality of the expression. This establishes how many items there will be in the result of the expression, at compile time (i.e., without actually evaluating the result.
    
    Overrides:
    
    getCardinality in class Expression
    
    Returns:
    
    one of the values Cardinality.ONE_OR_MORE, Cardinality.ZERO_OR_MORE, Cardinality.EXACTLY_ONE, Cardinality.ZERO_OR_ONE, Cardinality.EMPTY. This default implementation returns ZERO_OR_MORE (which effectively gives no information).
  - computeSpecialProperties
```
protected int computeSpecialProperties()
```
    Compute the special properties of this expression. These properties are denoted by a bit-significant integer, possible values are in class StaticProperty. The "special" properties are properties other than cardinality and dependencies, and most of them relate to properties of node sequences, for example whether the nodes are in document order.
    
    Overrides:
    
    computeSpecialProperties in class Expression
    
    Returns:
    
    the special properties, as a bit-significant integer
  - getImplementationMethod
```
public int getImplementationMethod()
```
    An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided directly. The other methods will always be available indirectly, using an implementation that relies on one of the other methods.
    
    Overrides:
    
    getImplementationMethod in class Expression
    
    Returns:
    
    the implementation method, for example Expression.ITERATE_METHOD or Expression.EVALUATE_METHOD or Expression.PROCESS_METHOD
  - iterateSubExpressions
```
public java.util.Iterator iterateSubExpressions()
```
    Get the immediate sub-expressions of this expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.
    
    Overrides:
    
    iterateSubExpressions in class Expression
    
    Returns:
    
    an iterator containing the sub-expressions of this expression
  - replaceSubExpression
```
public boolean replaceSubExpression(Expression original,
                                    Expression replacement)
```
    Replace one subexpression by a replacement subexpression
    
    Overrides:
    
    replaceSubExpression in class Expression
    
    Parameters:
    
    original - the original subexpression
    
    replacement - the replacement subexpression
    
    Returns:
    
    true if the original subexpression is found
  - computeCardinality
```
protected int computeCardinality()
```
    Compute the static cardinality of this expression
    
    Specified by:
    
    computeCardinality in class Expression
    
    Returns:
    
    the computed cardinality, as one of the values StaticProperty.ALLOWS_ZERO_OR_ONE, StaticProperty.EXACTLY_ONE, StaticProperty.ALLOWS_ONE_OR_MORE, StaticProperty.ALLOWS_ZERO_OR_MORE
  - copy
```
public Expression copy()
```
    Copy an expression. This makes a deep copy.
    
    Specified by:
    
    copy in class Expression
    
    Returns:
    
    the copy of the original expression
  - explain
```
public void explain(ExpressionPresenter out)
```
    Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
    
    Specified by:
    
    explain in class Expression
    
    Parameters:
    
    out - the expression presenter used to display the structure
  - getItemType
```
public ItemType getItemType(TypeHierarchy th)
```
    Determine the data type of the expression, if possible. All expression return sequences, in general; this method determines the type of the items within the sequence, assuming that (a) this is known in advance, and (b) it is the same for all items in the sequence.
    
    This method should always return a result, though it may be the best approximation that is available at the time.
    
    Specified by:
    
    getItemType in class Expression
    
    Parameters:
    
    th - the type hierarchy cache
    
    Returns:
    
    a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)
  - promote
```
public Expression promote(PromotionOffer offer)
                   throws XPathException
```
    Offer promotion for this subexpression. The offer will be accepted if the subexpression is not dependent on the factors (e.g. the context item) identified in the PromotionOffer. By default the offer is not accepted - this is appropriate in the case of simple expressions such as constant values and variable references where promotion would give no performance advantage. This method is always called at compile time.
    
    Overrides:
    
    promote in class Expression
    
    Parameters:
    
    offer - details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression
    
    Returns:
    
    if the offer is not accepted, return this expression unchanged. Otherwise return the result of rewriting the expression to promote this subexpression
    
    Throws:
    
    XPathException - if any error is detected
  - iterate
```
public SequenceIterator iterate(XPathContext context)
                         throws XPathException
```
    Return an Iterator to iterate over the values of a sequence. The value of every expression can be regarded as a sequence, so this method is supported for all expressions. This default implementation handles iteration for expressions that return singleton values: for non-singleton expressions, the subclass must provide its own implementation.
    
    Specified by:
    
    iterate in interface SequenceIterable
    
    Overrides:
    
    iterate in class Expression
    
    Parameters:
    
    context - supplies the context for evaluation
    
    Returns:
    
    a SequenceIterator that can be used to iterate over the result of the expression
    
    Throws:
    
    XPathException - if any dynamic error occurs evaluating the expression

Class ConditionalSorter

Field Summary

Fields inherited from class net.sf.saxon.expr.Expression

Constructor Summary

Method Summary

Methods inherited from class net.sf.saxon.expr.Expression

Methods inherited from class java.lang.Object

Constructor Detail

ConditionalSorter

Method Detail

getCondition

getDocumentSorter

getCardinality

computeSpecialProperties

getImplementationMethod

iterateSubExpressions

replaceSubExpression

computeCardinality

copy

explain

getItemType

promote

iterate