Package org.checkerframework.checker.index.qual

Annotation Interface 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.type.incompatible)
    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:
See the Checker Framework Manual:
Index Checker

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static @interface 
    EnsuresLTLengthOf.List
    A wrapper annotation that makes the EnsuresLTLengthOf annotation repeatable.

  • 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 Details

    • value

      @JavaExpression String[] value
      The Java expressions that are less than the length of the given sequences on successful method termination.
      See the Checker Framework Manual:
      Syntax of Java expressions

    • targetValue

      @JavaExpression @QualifierArgument("value") String[] targetValue
      Sequences, each of which is longer than the each of the expressions' value 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:
      {}