Class CollatingAtomicComparer

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

    public class CollatingAtomicComparer
    extends java.lang.Object
    implements AtomicComparer
    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.
    Author:
    Michael H. Kay
    See Also:
    Serialized Form
    • Constructor Summary

      Constructors 
      Constructor Description
      CollatingAtomicComparer​(java.util.Comparator collator, Platform platform)
      Create an GenericAtomicComparer
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int compare​(java.lang.Object a, java.lang.Object b)
      Compare two AtomicValue objects according to the rules for their data type.
      boolean comparesEqual​(AtomicValue a, AtomicValue b)
      Compare two AtomicValue objects for equality according to the rules for their data type.
      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, reversed, thenComparing, thenComparing, thenComparing, thenComparingDouble, thenComparingInt, thenComparingLong
    • Constructor Detail

      • CollatingAtomicComparer

        public CollatingAtomicComparer​(java.util.Comparator collator,
                                       Platform platform)
        Create an GenericAtomicComparer
        Parameters:
        collator - the collation to be used
        platform - used to obtain collation keys.
    • 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 AtomicComparer
        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 a0 if a>b
        Throws:
        java.lang.ClassCastException - if the objects are not comparable
      • 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.
        Specified by:
        comparesEqual in interface AtomicComparer
        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:
        java.lang.ClassCastException - if the objects are not comparable
      • 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.
        Specified by:
        getComparisonKey in interface AtomicComparer