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From "Woonsan Ko (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LANG-1158) StrSubstitutor - escape character not working just before a variable
Date Thu, 23 Jul 2015 20:30:05 GMT

    [ https://issues.apache.org/jira/browse/LANG-1158?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14639447#comment-14639447
] 

Woonsan Ko commented on LANG-1158:
----------------------------------

Anthony gave a good explanation about what the escape character means and how I can circumvent
the issue in the user@ list [1]:

{noformat}
The escape character just tells StrSubstitutor "Ignore the following
variable reference." When you change the default escape character, you
don't need to use it get a dollar sign before a variable reference in your
interpolated string. Try the following:

@Test
    public void testReplaceEscapingDollarSign() {
        values.put("amount", "20.00");

        final StrSubstitutor sub = new StrSubstitutor(values);
        sub.setEscapeChar('<');

        String replaceTemplate = "The <${animal} jumps over the ${target}.";
        String expectedResult = "The ${animal} jumps over the lazy dog.";
        String replacedResult = sub.replace(replaceTemplate);
        assertEquals(expectedResult, replacedResult);

        replaceTemplate = "The ${animal} paid $${amount} to jump over
the ${target}.";
        expectedResult = "The quick brown fox paid $20.00 to jump over
the lazy dog.";
        replacedResult = sub.replace(replaceTemplate);
        assertEquals(expectedResult, replacedResult);
    }
{noformat}

{noformat}
Sorry, the second sentence in the first paragraph should read: "When you
change the default escape character, you don't need to use it _to_ get a
dollar sign before a variable reference in your interpolated string."

To explain a little more, consider what happens to " $${amount}" when
you're using StrSubstitutor's default escape character. StrSubstitutor sees
that you've got a variable reference ("${amount}"), and that you've got the
escape character ("$") before it, so it replaces "$${amount}" with
"${amount}".

Now consider what happens to " $${amount}" when you've set StrSubstitutor's
escape character to something other than the default. StrSubstitutor sees
the variable reference ("${amount}"), notes that the character ("$") before
the variable reference is _not_ the user-defined escape character, and so
replaces "${amount}" with the appropriate value form the map.
{noformat}

I think I can live with using a different escape character for my use case. So I'll close
this issue.

[1] http://markmail.org/message/6p74g52hxkdaswtv

> StrSubstitutor - escape character not working just before a variable
> --------------------------------------------------------------------
>
>                 Key: LANG-1158
>                 URL: https://issues.apache.org/jira/browse/LANG-1158
>             Project: Commons Lang
>          Issue Type: Bug
>    Affects Versions: 3.4
>            Reporter: Woonsan Ko
>
> I tried to use the following, expecting "...ick brown fox paid $20.00 to jump over the
la…":
> {code}
>     // In org.apache.commons.lang3.text.StrSubstitutorTest.java locally
>     // after cloning https://github.com/woonsan/commons-lang.
>     @Test
>     public void testReplaceEscapingDollarSign() {
>         values.put("amount", "20.00");
>         doTestReplace("The quick brown fox paid $20.00 to jump over
> the lazy dog.",
>                       "The ${animal} paid $$${amount} to jump over the
> ${target}.", true);
>     }
> {code}
> {noformat}
> (I put double dollar signs like $$${amount} because $ is the default escape character.)
> Because I put three dollar signs in total, it should give one dollar sign followed by
the resolved amount value: "$20.00".
> But, the result was:"...ick brown fox paid $${amount} to jump over the la…".
> {noformat}
> I also tried using a different escape character like this:
> {code}
>     @Test
>     public void testReplaceEscapingDollarSign() {
>         values.put("amount", "20.00");
>         final StrSubstitutor sub = new StrSubstitutor(values);
>         sub.setEscapeChar('<');
>         String replaceTemplate = "The <${animal} jumps over the ${target}.";
>         String expectedResult = "The ${animal} jumps over the lazy dog.";
>         String replacedResult = sub.replace(replaceTemplate);
>         assertEquals(expectedResult, replacedResult);
>         replaceTemplate = "The ${animal} paid <$${amount} to jump over the ${target}.";
>         expectedResult = "The quick brown fox paid $20.00 to jump over the lazy dog.";
>         replacedResult = sub.replace(replaceTemplate);
>         assertEquals(expectedResult, replacedResult);
>     }
> {code}
> However, it fails like this:
> {noformat}
> Tests run: 41, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.048 sec <<<
FAILURE! - in org.apache.commons.lang3.text.StrSubstitutorTest
> testReplaceEscapingDollarSign(org.apache.commons.lang3.text.StrSubstitutorTest)  Time
elapsed: 0.009 sec  <<< FAILURE!
> org.junit.ComparisonFailure: expected:<...uick brown fox paid []$20.00 to jump over
...> but was:<...uick brown fox paid [<]$20.00 to jump over ...>
> 	at org.junit.Assert.assertEquals(Assert.java:115)
> 	at org.junit.Assert.assertEquals(Assert.java:144)
> 	at org.apache.commons.lang3.text.StrSubstitutorTest.testReplaceEscapingDollarSign(StrSubstitutorTest.java:182)
> {noformat}
> {noformat}
> The second assertion failed. So, it seems working in case of "<${animal}", but not
working in case of "<$${amount}".
> {noformat}
> I think escape character handling is inconsistent.



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