net.sf.saxon.sort
Class CollatingAtomicComparer
java.lang.Object
net.sf.saxon.sort.CollatingAtomicComparer
- AtomicComparer, Serializable
public class CollatingAtomicComparer
extends java.lang.Object
An AtomicComparer used for comparing strings, untypedAtomic values, and URIs using a collation.
A CollatingAtomicComparer is used when it is known in advance that both operands will be of these
types. 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.
CollatingAtomicComparer
public CollatingAtomicComparer(StringCollator collator,
Platform platform)
Create an GenericAtomicComparer
collator
- the collation to be used. If the method is called at compile time, this should
be a NamedCollation so that it can be cloned at run-time.platform
- used to obtain collation keys.
compareAtomicValues
public int compareAtomicValues(AtomicValue a,
AtomicValue b)
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.
- compareAtomicValues in interface AtomicComparer
a
- the first object to be compared. It is intended that this should be an instance
of AtomicValue, though this restriction is not enforced. If it is a StringValue, the
collator is used to compare the values, otherwise the value must implement the java.util.Comparable
interface.b
- the second object to be compared. This must be comparable with the first object: for
example, if one is a string, they must both be strings.
comparesEqual
public boolean comparesEqual(AtomicValue a,
AtomicValue b)
Compare two AtomicValue objects for equality according to the rules for their data type. UntypedAtomic
values are compared by converting to the type of the other operand.
- comparesEqual in interface AtomicComparer
a
- the first object to be compared. It is intended that this should be an instance
of AtomicValue, though this restriction is not enforced. If it is a StringValue, the
collator is used to compare the values, otherwise the value must implement the equals() method.b
- the second object to be compared. This must be comparable with the first object: for
example, if one is a string, they must both be strings.
getCollationURI
public String getCollationURI()
Get the collation URI
getComparisonKey
public ComparisonKey getComparisonKey(AtomicValue a)
Get a comparison key for an object. This must satisfy the rule that if two objects are equal,
then their comparison keys are equal, and vice versa. There is no requirement that the
comparison keys should reflect the ordering of the underlying objects.
- getComparisonKey in interface AtomicComparer
provideContext
public AtomicComparer provideContext(XPathContext context)
Supply the dynamic context in case this is needed for the comparison
- provideContext in interface AtomicComparer
context
- the dynamic evaluation context
- either the original AtomicComparer, or a new AtomicComparer in which the context
is known. The original AtomicComparer is not modified