Package net.sf.saxon.expr.sort
Class CodepointCollatingComparer
java.lang.Object
net.sf.saxon.expr.sort.CodepointCollatingComparer
- All Implemented Interfaces:
AtomicComparer
An AtomicComparer used for comparing strings, untypedAtomic values, and URIs using the Unicode codepoint
collation.
A CodepointCollatingComparer is used when it is known in advance that both operands will be of these
types, and when the collation is the unicode codepoint collation.
This enables all conversions and promotions to be bypassed: the string values of both operands
are simply extracted and passed to the collator for comparison.
The difference between using this class and using the underlying CodepointCollator directly is that the compare() method in this class expects two instances of AtomicValue as its operands, whereas the underlying class expects two instances of java.lang.String. This class makes use of the extra information held in the wrapping StringValue object, specifically, the knowledge of whether the string contains surrogate pairs.
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Method Summary
Modifier and TypeMethodDescriptionint
Compare two AtomicValue objects according to the rules for their data type.boolean
Compare two AtomicValue objects for equality.Get the collation used by this AtomicComparer if anystatic CodepointCollatingComparer
Get the singular instance of this classprovideContext
(XPathContext context) Supply the dynamic context in case this is needed for the comparisonsave()
Create a string representation of this AtomicComparer that can be saved in a compiled package and used to reconstitute the AtomicComparer when the package is reloaded
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Method Details
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getInstance
Get the singular instance of this class- Returns:
- the singleton instance
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getCollator
Description copied from interface:AtomicComparer
Get the collation used by this AtomicComparer if any- Specified by:
getCollator
in interfaceAtomicComparer
- Returns:
- the collation used for comparing strings, or null if not applicable
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provideContext
Supply the dynamic context in case this is needed for the comparison- Specified by:
provideContext
in interfaceAtomicComparer
- Parameters:
context
- the dynamic evaluation context- Returns:
- either the original AtomicComparer, or a new AtomicComparer in which the context is known. The original AtomicComparer is not modified
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compareAtomicValues
Compare two AtomicValue objects according to the rules for their data type. UntypedAtomic values are compared as if they were strings; if different semantics are wanted, the conversion must be done by the caller.- Specified by:
compareAtomicValues
in interfaceAtomicComparer
- Parameters:
a
- the first object to be compared. This must be either be an instance of AtomicValue, or null to represent an empty sequence. Empty collates before non-empty.b
- the second object to be compared. This must be either be an instance of AtomicValue, or null to represent an empty sequence.- Returns:
- <0 if a<b, 0 if a=b, >0 if a>b
- Throws:
ClassCastException
- if the objects are not comparable
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comparesEqual
Compare two AtomicValue objects for equality. The values must be instances of xs:string or a type derived from xs:string. The method will also handle xs:untypedAtomic and xs:anyURI values.- Specified by:
comparesEqual
in interfaceAtomicComparer
- Parameters:
a
- the first object to be compared.b
- the second object to be compared.- Returns:
- true if the values are equal, false if not
- Throws:
ClassCastException
- if either value is not xs:string or a subtype
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save
Create a string representation of this AtomicComparer that can be saved in a compiled package and used to reconstitute the AtomicComparer when the package is reloaded- Specified by:
save
in interfaceAtomicComparer
- Returns:
- a string representation of the AtomicComparer
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