net.sf.saxon.sort
Class AtomicComparer
java.lang.Object
net.sf.saxon.sort.AtomicComparer
- All Implemented Interfaces:
- Serializable, Comparator
public class AtomicComparer
- extends Object
- implements Comparator, Serializable
A Comparator used for comparing atomic values of arbitrary item types. It encapsulates
a Collator that is used when the values to be compared are strings. It also supports
a separate method for testing equality of items, which can be used for data types that
are not ordered.
- Author:
- Michael H. Kay (michael.h.kay@ntlworld.com)
- See Also:
- Serialized Form
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
AtomicComparer
public AtomicComparer(Comparator collator)
compare
public int compare(Object a,
Object 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.
- Specified by:
compare
in interface Comparator
- Parameters:
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.
- Returns:
- <0 if a0 if a>b
- Throws:
ClassCastException
- if the objects are not comparable
comparesEqual
public boolean comparesEqual(Object a,
Object b)
- Compare two AtomicValue objects for equality 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.
- Parameters:
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.
- Returns:
- <0 if a0 if a>b
- Throws:
ClassCastException
- if the objects are not comparable
getComparisonKey
public Object getComparisonKey(Object 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.