Class TextComparer

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

public class TextComparer extends Object implements AtomicComparer, Serializable
A Comparer used for comparing sort keys when data-type="text". The items to be compared are converted to strings, and the strings are then compared using an underlying collator
Author:
Michael H. Kay
See Also:
  • Constructor Details

  • Method Details

    • getBaseComparer

      public AtomicComparer getBaseComparer()
      Get the underlying comparer (which doesn't do conversion to string)
    • provideContext

      public AtomicComparer provideContext(XPathContext context)
      Supply the dynamic context in case this is needed for the comparison
      Specified by:
      provideContext in interface AtomicComparer
      Parameters:
      context - the dynamic evaluation context
      Returns:
      either the original AtomicComparer, or a new AtomicComparer in which the context is known. The original AtomicComparer is not modified
      Throws:
      NoDynamicContextException - if the context is an "early evaluation" (compile-time) context
    • compareAtomicValues

      public int compareAtomicValues(AtomicValue a, AtomicValue b) throws ClassCastException, NoDynamicContextException
      Compare two Items by converting them to strings and comparing the string values.
      Specified by:
      compareAtomicValues in interface AtomicComparer
      Parameters:
      a - the first Item to be compared.
      b - the second Item to be compared.
      Returns:
      invalid input: '<'0 if ainvalid input: '<'b, 0 if a=b, >0 if a>b
      Throws:
      ClassCastException - if the objects are not Items, or are items that cannot be convered to strings (e.g. QNames)
      NoDynamicContextException - if this comparer required access to dynamic context information, notably the implicit timezone, and this information is not available. In general this happens if a context-dependent comparison is attempted at compile-time, and it signals the compiler to generate code that tries again at run-time.
    • comparesEqual

      public boolean comparesEqual(AtomicValue a, AtomicValue b) throws NoDynamicContextException
      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.
      b - the second object to be compared.
      Returns:
      true if the values are equal, false if not
      Throws:
      ClassCastException - if the objects are not comparable
      NoDynamicContextException
    • getComparisonKey

      public ComparisonKey getComparisonKey(AtomicValue a) throws NoDynamicContextException
      Get a comparison key for an object. This must satisfy the rule that if two objects are equal according to the XPath eq operator, then their comparison keys are equal according to the Java equals() method, 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
      Throws:
      NoDynamicContextException