[jira] [Created] (UIMA-5845) Inconsistent behavior on going beyond index limits in SelectFS

[Richard Eckart de Castilho (JIRA)]

Richard Eckart de Castilho created UIMA-5845:
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             Summary: Inconsistent behavior on going beyond index limits in 
SelectFS
                 Key: UIMA-5845
                 URL: https://issues.apache.org/jira/browse/UIMA-5845
             Project: UIMA
          Issue Type: Bug
          Components: Core Java Framework
    Affects Versions: 3.0.0SDK
            Reporter: Richard Eckart de Castilho


The behavior of trying to address annotations outside the index appears to be 
inconsistent.

For example, the following call returns `null`:

{code}
    String text = "one two three";
    tokenBuilder.buildTokens(jCas, text);

    List<Token> tokens = new ArrayList<Token>(select(jCas, Token.class));
    
    for (Token token : tokens) {
      new AnalyzedText(jCas, token.getBegin(), token.getEnd()).addToIndexes();
    }    
    
    Token firstToken = tokens.get(0);

    AnalyzedText x = jCas.select(AnalyzedText.class).preceding(firstToken, 
0).get();
{code}

However, this code trying go from the end of the index to before the first item 
throws a CASRuntime exception:

{code}
    String text = "Rot wood cheeses dew?";
    tokenBuilder.buildTokens(jCas, text);

    assertThatExceptionOfType(CASRuntimeException.class)
        .isThrownBy(() -> jCas.select(Token.class).backwards().get(4))
        .withMessage("CAS does not contain any '" + Token.class.getName() + "' 
instances  shifted by: 4.");
{code}

It would seem reasonably to either always return null or to always thrown an 
exception. If an exception is thrown, it would seem reasonable to introduce a 
subtype of the CASRuntimeException, e.g. a CASIndexOutOfBounds exception or 
something the likes. CASRuntimeException seems very general.



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