Class GenericAtomicComparer

java.lang.Object
net.sf.saxon.sort.GenericAtomicComparer
All Implemented Interfaces:
Serializable, Comparator, AtomicComparer

public class GenericAtomicComparer extends Object implements AtomicComparer, 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
See Also:
  • Constructor Details

    • GenericAtomicComparer

      public GenericAtomicComparer(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(Comparator collator, Configuration config)
  • Method Details

    • makeAtomicComparer

      public static AtomicComparer makeAtomicComparer(int type0, int type1, 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(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 AtomicComparer
      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:
      invalid input: '<'0 if ainvalid input: '<'b, 0 if a=b, >0 if a>b
      Throws:
      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:
      invalid input: '<'0 if ainvalid input: '<'b, 0 if a=b, >0 if a>b
      Throws:
      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