java.lang.Object
- net.sf.saxon.expr.Expression
- - net.sf.saxon.expr.BinaryExpression
  - - net.sf.saxon.expr.SingletonComparison

All Implemented Interfaces:

java.io.Serializable, javax.xml.transform.SourceLocator, LocationProvider, SaxonLocator, ComparisonExpression, EvaluableItem, SequenceIterable, InstructionInfo, org.xml.sax.Locator
```
public class SingletonComparison
extends BinaryExpression
implements ComparisonExpression
```
Class to handle comparisons of singletons. Unlike ValueComparison, this class converts untyped atomic values to the type of the other argument, and returns false (rather than ()) if either operand is ().

See Also:

Serialized Form

Field Summary
- Fields inherited from class net.sf.saxon.expr.BinaryExpression
  operand0, operand1, operator
- Fields inherited from class net.sf.saxon.expr.Expression
  EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties

Constructor Summary

Constructors
Constructor Description

SingletonComparison(Expression p1, int operator, Expression p2)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`int`	`computeCardinality()`	Determine the static cardinality.
`boolean`	`convertsUntypedToOther()`	Determine whether untyped atomic values should be converted to the type of the other operand
`Expression`	`copy()`	Copy an expression.
`protected java.lang.String`	`displayOperator()`
`boolean`	`effectiveBooleanValue(XPathContext context)`	Evaluate the expression in a boolean context
`Item`	`evaluateItem(XPathContext context)`	Evaluate the expression in a given context
`AtomicComparer`	`getAtomicComparer()`	Get the AtomicComparer used to compare atomic values.
`ItemType`	`getItemType(TypeHierarchy th)`	Determine the data type of the expression
`int`	`getSingletonOperator()`	Get the primitive (singleton) operator used: one of Token.FEQ, Token.FNE, Token.FLT, Token.FGT, Token.FLE, Token.FGE
`void`	`setAtomicComparer(AtomicComparer comp)`

Methods inherited from class net.sf.saxon.expr.BinaryExpression
computeSpecialProperties, equals, explain, getOperands, getOperator, hashCode, isAssociative, isCommutative, isInverse, iterateSubExpressions, optimize, promote, replaceSubExpression, setFlattened, simplify, toString, typeCheck

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

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

Methods inherited from interface net.sf.saxon.expr.ComparisonExpression
getOperands

- Constructor Detail
  - SingletonComparison
```
public SingletonComparison(Expression p1,
                           int operator,
                           Expression p2)
```
- Method Detail
  - setAtomicComparer
```
public void setAtomicComparer(AtomicComparer comp)
```
  - getAtomicComparer
```
public AtomicComparer getAtomicComparer()
```
    Description copied from interface: ComparisonExpression
    
    Get the AtomicComparer used to compare atomic values. This encapsulates any collation that is used
    
    Specified by:
    
    getAtomicComparer in interface ComparisonExpression
  - getSingletonOperator
```
public int getSingletonOperator()
```
    Description copied from interface: ComparisonExpression
    
    Get the primitive (singleton) operator used: one of Token.FEQ, Token.FNE, Token.FLT, Token.FGT, Token.FLE, Token.FGE
    
    Specified by:
    
    getSingletonOperator in interface ComparisonExpression
  - convertsUntypedToOther
```
public boolean convertsUntypedToOther()
```
    Determine whether untyped atomic values should be converted to the type of the other operand
    
    Specified by:
    
    convertsUntypedToOther in interface ComparisonExpression
    
    Returns:
    
    true if untyped values should be converted to the type of the other operand, false if they should be converted to strings.
  - computeCardinality
```
public int computeCardinality()
```
    Determine the static cardinality. Returns [1..1]
    
    Overrides:
    
    computeCardinality in class BinaryExpression
    
    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
  - getItemType
```
public ItemType getItemType(TypeHierarchy th)
```
    Determine the data type of the expression
    
    Specified by:
    
    getItemType in class Expression
    
    Parameters:
    
    th - the type hierarchy cache
    
    Returns:
    
    Type.BOOLEAN
  - 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
  - evaluateItem
```
public Item evaluateItem(XPathContext context)
                  throws XPathException
```
    Evaluate the expression in a given context
    
    Specified by:
    
    evaluateItem in interface EvaluableItem
    
    Overrides:
    
    evaluateItem in class Expression
    
    Parameters:
    
    context - the given context for evaluation
    
    Returns:
    
    a BooleanValue representing the result of the numeric comparison of the two operands
    
    Throws:
    
    XPathException - if any dynamic error occurs evaluating the expression
  - effectiveBooleanValue
```
public boolean effectiveBooleanValue(XPathContext context)
                              throws XPathException
```
    Evaluate the expression in a boolean context
    
    Overrides:
    
    effectiveBooleanValue in class Expression
    
    Parameters:
    
    context - the given context for evaluation
    
    Returns:
    
    a boolean representing the result of the numeric comparison of the two operands
    
    Throws:
    
    XPathException - if any dynamic error occurs evaluating the expression
  - displayOperator
```
protected java.lang.String displayOperator()
```
    Overrides:
    
    displayOperator in class BinaryExpression

Class SingletonComparison

Field Summary

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

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

Constructor Summary

Method Summary

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

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

Methods inherited from class java.lang.Object

Methods inherited from interface net.sf.saxon.expr.ComparisonExpression

Constructor Detail

SingletonComparison

Method Detail

setAtomicComparer

getAtomicComparer

getSingletonOperator

convertsUntypedToOther

computeCardinality

getItemType

copy

evaluateItem

effectiveBooleanValue

displayOperator