Class GenericAtomicComparer

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

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

      All Methods Static 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.
      static AtomicComparer makeAtomicComparer​(int type0, int type1, java.util.Comparator collator, Configuration config)
      Factory method to make a GenericAtomicComparer for values of known types
      • 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

      • GenericAtomicComparer

        public GenericAtomicComparer​(java.util.Comparator collator,
                                     XPathContext conversion)
        Create an GenericAtomicComparer
        Parameters:
        collator - the collation to be used
        conversion - a context, used when converting untyped atomic values to the target type.
      • GenericAtomicComparer

        public GenericAtomicComparer​(java.util.Comparator collator,
                                     Configuration config)
    • Method Detail

      • makeAtomicComparer

        public static AtomicComparer makeAtomicComparer​(int type0,
                                                        int type1,
                                                        java.util.Comparator collator,
                                                        Configuration config)
        Factory method to make a GenericAtomicComparer for values of known types
        Parameters:
        type0 - primitive type of the first operand
        type1 - primitive type of the second operand
        collator - the collation to be used, if any
        config - the configuration
        Returns:
        a GenericAtomicComparer for values of known types
      • 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