Package net.sf.saxon.expr
Class GeneralComparison
- java.lang.Object
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- net.sf.saxon.expr.ComputedExpression
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- net.sf.saxon.expr.BinaryExpression
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- net.sf.saxon.expr.GeneralComparison
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- All Implemented Interfaces:
java.io.Serializable
,javax.xml.transform.SourceLocator
,ComparisonExpression
,Container
,Expression
,InstructionInfoProvider
public class GeneralComparison extends BinaryExpression implements ComparisonExpression
GeneralComparison: a boolean expression that compares two expressions for equals, not-equals, greater-than or less-than. This implements the operators =, !=, <, >, etc. This implementation is not used when in backwards-compatible mode- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description protected AtomicComparer
comparer
protected int
singletonOperator
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Fields inherited from class net.sf.saxon.expr.BinaryExpression
operand0, operand1, operator
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Fields inherited from class net.sf.saxon.expr.ComputedExpression
locationId, staticProperties
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Fields inherited from interface net.sf.saxon.expr.Expression
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD
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Constructor Summary
Constructors Constructor Description GeneralComparison(Expression p0, int op, Expression p1)
Create a relational expression identifying the two operands and the operator
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description protected static boolean
compare(AtomicValue a1, int operator, AtomicValue a2, AtomicComparer comparer, XPathContext context)
Compare two atomic valuesint
computeCardinality()
Determine the static cardinality.boolean
convertsUntypedToOther()
Determine whether untyped atomic values should be converted to the type of the other operandprotected java.lang.String
displayOperator()
boolean
effectiveBooleanValue(XPathContext context)
Evaluate the expression in a boolean contextItem
evaluateItem(XPathContext context)
Evaluate the expression in a given contextAtomicComparer
getAtomicComparer()
Get the AtomicComparer used to compare atomic values.protected GeneralComparison
getInverseComparison()
ItemType
getItemType(TypeHierarchy th)
Determine the data type of the expressionint
getSingletonOperator()
Get the primitive (singleton) operator used: one of Token.FEQ, Token.FNE, Token.FLT, Token.FGT, Token.FLE, Token.FGEExpression
optimize(Optimizer opt, StaticContext env, ItemType contextItemType)
Optimize the expressionExpression
typeCheck(StaticContext env, ItemType contextItemType)
Type-check the expression-
Methods inherited from class net.sf.saxon.expr.BinaryExpression
computeSpecialProperties, display, equals, getOperands, getOperator, hashCode, isAssociative, isCommutative, isInverse, iterateSubExpressions, promote, replaceSubExpression, simplify
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Methods inherited from class net.sf.saxon.expr.ComputedExpression
adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, evaluateAsString, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, iterate, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, setParentExpression, suppressValidation, typeError
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Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface net.sf.saxon.expr.ComparisonExpression
getOperands
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Field Detail
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singletonOperator
protected int singletonOperator
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comparer
protected transient AtomicComparer comparer
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Constructor Detail
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GeneralComparison
public GeneralComparison(Expression p0, int op, Expression p1)
Create a relational expression identifying the two operands and the operator- Parameters:
p0
- the left-hand operandop
- the operator, as a token returned by the Tokenizer (e.g. Token.LT)p1
- the right-hand operand
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Method Detail
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getAtomicComparer
public AtomicComparer getAtomicComparer()
Get the AtomicComparer used to compare atomic values. This encapsulates any collation that is used- Specified by:
getAtomicComparer
in interfaceComparisonExpression
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getSingletonOperator
public int getSingletonOperator()
Get the primitive (singleton) operator used: one of Token.FEQ, Token.FNE, Token.FLT, Token.FGT, Token.FLE, Token.FGE- Specified by:
getSingletonOperator
in interfaceComparisonExpression
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convertsUntypedToOther
public boolean convertsUntypedToOther()
Determine whether untyped atomic values should be converted to the type of the other operand- Specified by:
convertsUntypedToOther
in interfaceComparisonExpression
- Returns:
- true if untyped values should be converted to the type of the other operand, false if they should be converted to strings.
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computeCardinality
public int computeCardinality()
Determine the static cardinality. Returns [1..1]- Overrides:
computeCardinality
in classBinaryExpression
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typeCheck
public Expression typeCheck(StaticContext env, ItemType contextItemType) throws XPathException
Type-check the expression- Specified by:
typeCheck
in interfaceExpression
- Overrides:
typeCheck
in classBinaryExpression
- Parameters:
env
- the static context of the expressioncontextItemType
- the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set toType.ITEM_TYPE
- Returns:
- the checked expression
- Throws:
StaticError
- if an error is discovered during this phase (typically a type error)XPathException
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optimize
public Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType) throws XPathException
Optimize the expression- Specified by:
optimize
in interfaceExpression
- Overrides:
optimize
in classBinaryExpression
- Parameters:
opt
- the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.env
- the static context of the expressioncontextItemType
- the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set toType.ITEM_TYPE
- Returns:
- the checked expression
- Throws:
net.sf.saxon.trans.StaticError
- if an error is discovered during this phase (typically a type error)XPathException
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evaluateItem
public Item evaluateItem(XPathContext context) throws XPathException
Evaluate the expression in a given context- Specified by:
evaluateItem
in interfaceExpression
- Overrides:
evaluateItem
in classComputedExpression
- 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
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effectiveBooleanValue
public boolean effectiveBooleanValue(XPathContext context) throws XPathException
Evaluate the expression in a boolean context- Specified by:
effectiveBooleanValue
in interfaceExpression
- Overrides:
effectiveBooleanValue
in classComputedExpression
- 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
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compare
protected static boolean compare(AtomicValue a1, int operator, AtomicValue a2, AtomicComparer comparer, XPathContext context) throws XPathException
Compare two atomic values- Throws:
XPathException
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getItemType
public ItemType getItemType(TypeHierarchy th)
Determine the data type of the expression- Specified by:
getItemType
in interfaceExpression
- Parameters:
th
-- Returns:
- Type.BOOLEAN
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getInverseComparison
protected GeneralComparison getInverseComparison()
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displayOperator
protected java.lang.String displayOperator()
- Overrides:
displayOperator
in classBinaryExpression
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