## net.sf.saxon.sort
Class AtomicSortComparer

    java.lang.Object
      net.sf.saxon.sort.AtomicSortComparer

All Implemented Interfaces:
  java.util.Comparator, java.io.Serializable

public class AtomicSortComparer
extends java.lang.Object
implements java.util.Comparator, java.io.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. The AtomicSortComparer is identical to the AtomicComparer except for its handling of NaN: it treats NaN values as lower than any other value, and NaNs as equal to each other.

See Also:
  Serialized Form

Nested Class Summary
`static class` `AtomicSortComparer.ComparisonKey` Inner class: an object used as a comparison key.

Constructor Summary
`AtomicSortComparer(java.util.Comparator collator, XPathContext conversion)`

Method Summary
`int` `compare(java.lang.Object a, java.lang.Object b)` Compare two AtomicValue objects according to the rules for their data type.
`AtomicSortComparer.ComparisonKey` `getComparisonKey(AtomicValue a)` Get a comparison key for an object.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Methods inherited from interface java.util.Comparator
`equals`

Constructor Detail

### AtomicSortComparer

    public AtomicSortComparer(java.util.Comparator collator,
                              XPathContext conversion)

Method Detail

### compare

    public int compare(java.lang.Object a,
                       java.lang.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 `java.util.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 a<b, 0 if a=b, >0 if a>b
  Throws:
    `java.lang.ClassCastException` - if the objects are not comparable

### getComparisonKey

    public AtomicSortComparer.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.