Package org.checkerframework.checker.index.qual

Annotation Type EnsuresLTLengthOf

  • @Documented
@Retention(RUNTIME)
@Target({METHOD,CONSTRUCTOR})
@PostconditionAnnotation(qualifier=LTLengthOf.class)
@InheritedAnnotation
@Repeatable(List.class)
public @interface EnsuresLTLengthOf
    Indicates that the value expressions evaluate to an integer whose value is less than the lengths of all the given sequences, if the method terminates successfully.

    Consider the following example, from the Index Checker's regression tests: 

     @EnsuresLTLengthOf(value = "end", targetValue = "array", offset = "#1 - 1")
  public void shiftIndex(@NonNegative int x) {
      int newEnd = end - x;
      if (newEnd < 0) throw new RuntimeException();
      end = newEnd;
  }
    where end is annotated as @NonNegative @LTEqLengthOf("array") int end;

    This method guarantees that end has type @LTLengthOf(value="array", offset="x - 1") after the method returns. This is useful in cases like this one: 

    
 public void useShiftIndex(@NonNegative int x) {
    // :: error: (argument)
    Arrays.fill(array, end, end + x, null);
    shiftIndex(x);
    Arrays.fill(array, end, end + x, null);
 }
    The first call to Arrays.fill is rejected (hence the comment about an error). But, after calling shiftIndex(x), end has an annotation that allows the end + x to be accepted as @LTLengthOf("array").
    See Also:
    LTLengthOf

    • Required Element Summary

      Required Elements 
      Modifier and Type Required Element Description
      String[] targetValue
      Sequences, each of which is longer than the each of the expressions' value on successful method termination.
      String[] value
      The Java expressions that are less than the length of the given sequences on successful method termination.

    • Optional Element Summary

      Optional Elements 
      Modifier and Type Optional Element Description
      String[] offset
      This expression plus each of the value expressions is less than the length of the sequence on successful method termination.

    • Element Detail

      • value

        @JavaExpression
String[] value
        The Java expressions that are less than the length of the given sequences on successful method termination.

      • offset

        @JavaExpression
@QualifierArgument("offset")
String[] offset
        This expression plus each of the value expressions is less than the length of the sequence on successful method termination. The offset element must ether be empty or the same length as targetValue.
        Returns:
        the offset expressions
        Default:
        {}