# \[SOLVED\] String::format silently fails (maybe 2.5.0 M3 issue)

**URL:** <https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948>\
**Category:** Scripts & Rules\
**Tags:** strings, formatting, milestone\
**Created:** [September 15, 2019, 9:10am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948 "2019-09-15T09:10:52Z")\
**Posts on this page:** 20\
**Page:** 1

<div class="post-metadata">

**Author:** ![miba](https://community.openhab.org/user_avatar/community.openhab.org/miba/32/33506_2.png) [@miba](https://community.openhab.org/u/miba)\
**Post date:** [September 15, 2019, 9:10am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/1 "2019-09-15T09:10:52Z")

</div>

I have recently upgraded to [openHAB 2.5.0 Milestone 3](https://community.openhab.org/t/openhab-milestone-builds/50359/391) from M2. I am not really sure whether this has something to do with that upgrade but my previously working code has an issue at a certain point. I have found out that a `String::format` statement silently fails. Here is my setup:

**Items**

```csv
Number Taupunkt_Differenz "Taupunktdifferenz Δtd [%.1f °C]" <humidity>

```

`Taupunkt_Differenz` is a calculated item out of 2 `doubleValue`s.

**myrule.rules**

```csv
rule "My rule"
when
	Item Taupunkt_Differenz changed
then
	val Number taupunkt_delta = Taupunkt_Differenz.state as DecimalType
	val td=1.2345
	logInfo("myrule.rules", "td=" + td + " | taupunkt_delta=" + taupunkt_delta)
	var String test1 = String::format("%.1f °C", td)
	logInfo("myrule.rules", "test1=" + test1)
	var String test2 = String::format("%.1f °C", taupunkt_delta)
	logInfo("myrule.rules", "test2=" + test2) // this line won't be reached!
	// ...
	// (more code)
	// ...
end

```

The complete log output is

```csv
2019-09-15 10:49:00.018 [INFO] [me.model.script.myrule.rules] - td=1.2345 | taupunkt_delta=0.8502743895760965
2019-09-15 10:49:00.025 [INFO] [me.model.script.myrule.rules] - test1=1,2 °C

```

and that’s it. The last `logInfo` is missing. So my impression is that the second `String::format` statement fails and the rule is exited without any error message because the following code is not executed.

I am quite sure that this code worked before. Does anybody have an idea what is going on here?

---

<div class="post-metadata">

**Author:** ![vzorglub](https://community.openhab.org/user_avatar/community.openhab.org/vzorglub/32/17166_2.png) [@vzorglub](https://community.openhab.org/u/vzorglub)\
**Post date:** [September 15, 2019, 9:38am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/2 "2019-09-15T09:38:11Z")

</div>

Did you add another test logInfo:

```php
	var String test1 = String::format("%.1f °C", td)
	logInfo("myrule.rules", "test1=" + test1)
	var String test2 = String::format("%.1f °C", taupunkt_delta)
        logInfo("TEST", "TEST")
	logInfo("myrule.rules", "test2=" + test2) // this line won't be reached!

```

Is that one logged?

---

<div class="post-metadata">

**Author:** ![miba](https://community.openhab.org/user_avatar/community.openhab.org/miba/32/33506_2.png) [@miba](https://community.openhab.org/u/miba)\
**Post date:** [September 15, 2019, 10:13am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/3 "2019-09-15T10:13:29Z")

</div>

> [@vzorglub](#):
>
> Is that one logged?

No, unfortunately not.

---

<div class="post-metadata">

**Author:** ![vzorglub](https://community.openhab.org/user_avatar/community.openhab.org/vzorglub/32/17166_2.png) [@vzorglub](https://community.openhab.org/u/vzorglub)\
**Post date:** [September 15, 2019, 10:19am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/4 "2019-09-15T10:19:50Z")

</div>

What about this:

```php
	//var String test2 = String::format("%.1f °C", taupunkt_delta)
        var String test2 = "TEST"
        logInfo("TEST", test2)

```

---

<div class="post-metadata">

**Author:** ![miba](https://community.openhab.org/user_avatar/community.openhab.org/miba/32/33506_2.png) [@miba](https://community.openhab.org/u/miba)\
**Post date:** [September 15, 2019, 10:25am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/5 "2019-09-15T10:25:32Z")

</div>

> [@vzorglub](#):
>
> What about this:

This one does work. Output as expected.

---

<div class="post-metadata">

**Author:** ![vzorglub](https://community.openhab.org/user_avatar/community.openhab.org/vzorglub/32/17166_2.png) [@vzorglub](https://community.openhab.org/u/vzorglub)\
**Post date:** [September 15, 2019, 10:28am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/6 "2019-09-15T10:28:08Z")

</div>

Ok so now we are sure it’s that line causing problems  
Delete it completely  
Save the file  
Type it in again (Not copy paste) there maybe some hidden stuff in it (Weird I know, it happens…)

---

<div class="post-metadata">

**Author:** ![miba](https://community.openhab.org/user_avatar/community.openhab.org/miba/32/33506_2.png) [@miba](https://community.openhab.org/u/miba)\
**Post date:** [September 15, 2019, 10:38am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/7 "2019-09-15T10:38:21Z")

</div>

> [@vzorglub](#):
>
> Delete it completely  
> Save the file  
> Type it in again (Not copy paste) there maybe some hidden stuff in it (Weird I know, it happens…)

I followed your directions but still no change. There must be something wrong with the float formatting because this here

```csv
logInfo(logName, "td=" + td + " | taupunkt_delta=" + taupunkt_delta)
var String test1 = String::format("%.1f °C", td)
logInfo(logName, "test1=" + test1)
var String test2 = String::format("%s", taupunkt_delta)
logInfo("TEST", "test2=" + test2)
var String test3 = String::format("%s", taupunkt_delta)
test3 = String::format("%.1f", taupunkt_delta)
logInfo("TEST", "test3=" + test3)

```

produces the following output (last logInfo not executed):

```csv
2019-09-15 12:34:30.009 [INFO] [me.model.script.myrules.rules] - td=1.2345 | taupunkt_delta=0.2726788936991973
2019-09-15 12:34:30.013 [INFO] [me.model.script.myrules.rules] - test1=1,2 °C
2019-09-15 12:34:30.018 [INFO] [.eclipse.smarthome.model.script.TEST] - test2=0.2726788936991973

```

Very strange.

---

<div class="post-metadata">

**Author:** ![vzorglub](https://community.openhab.org/user_avatar/community.openhab.org/vzorglub/32/17166_2.png) [@vzorglub](https://community.openhab.org/u/vzorglub)\
**Post date:** [September 15, 2019, 10:43am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/8 "2019-09-15T10:43:38Z")

</div>

And if you remove the third one, does the second one still appear?

---

<div class="post-metadata">

**Author:** ![rossko57](https://community.openhab.org/user_avatar/community.openhab.org/rossko57/32/70263_2.png) [@rossko57](https://community.openhab.org/u/rossko57)\
**Post date:** [September 15, 2019, 10:45am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/9 "2019-09-15T10:45:48Z")

</div>

> [@miba](#):
>
> test1=1,2 °C

Possible clue about language formatting (decimal separator)

---

<div class="post-metadata">

**Author:** ![miba](https://community.openhab.org/user_avatar/community.openhab.org/miba/32/33506_2.png) [@miba](https://community.openhab.org/u/miba)\
**Post date:** [September 15, 2019, 10:49am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/10 "2019-09-15T10:49:49Z")

</div>

> [@vzorglub](#):
>
> And if you remove the third one, does the second one still appear?

Yes.

---

<div class="post-metadata">

**Author:** ![miba](https://community.openhab.org/user_avatar/community.openhab.org/miba/32/33506_2.png) [@miba](https://community.openhab.org/u/miba)\
**Post date:** [September 15, 2019, 10:51am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/11 "2019-09-15T10:51:55Z")

</div>

> [@rossko57](#):
>
> Possible clue about language formatting (decimal separator)

Yes, that could be an issue. But in a different rule something like this

```csv
Klima_Keller.sendCommand(String::format("T=%.1f °C | φ=%.0f%% | td=%.1f °C", t, h, d))
logMessage += String::format("=%.1f °C (T=%.1f °C, φ=%.0f %%)", d, t, h)

```

works without a flaw.

---

<div class="post-metadata">

**Author:** ![rossko57](https://community.openhab.org/user_avatar/community.openhab.org/rossko57/32/70263_2.png) [@rossko57](https://community.openhab.org/u/rossko57)\
**Post date:** [September 15, 2019, 11:13am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/12 "2019-09-15T11:13:17Z")

</div>

> [@miba](#):
>
> val Number taupunkt\_delta = Taupunkt\_Differenz.state as DecimalType

What happens if you use instead

`val taupunkt_delta = Taupunkt_Differenz.state as Number`

Rules are bit loose about typing. Either “should” work of course.

---

<div class="post-metadata">

**Author:** ![miba](https://community.openhab.org/user_avatar/community.openhab.org/miba/32/33506_2.png) [@miba](https://community.openhab.org/u/miba)\
**Post date:** [September 15, 2019, 11:23am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/13 "2019-09-15T11:23:04Z")

</div>

> [@rossko57](#):
>
> What happens if you use instead
> 
> `val taupunkt_delta = Taupunkt_Differenz.state as Number`

This makes no difference, too. The `String::format` part still fails. I wonder why there are no error messages in the logs. It is just as if the rule will be left at this very point.

---

<div class="post-metadata">

**Author:** ![rossko57](https://community.openhab.org/user_avatar/community.openhab.org/rossko57/32/70263_2.png) [@rossko57](https://community.openhab.org/u/rossko57)\
**Post date:** [September 15, 2019, 11:34am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/14 "2019-09-15T11:34:42Z")

</div>

Very odd

val taupunkt\_delta = Taupunkt\_Differenz.state as Number  
val td=1.2345

should both result in Number objects, I think?  
Try  
`val Number td=1.2345`

> [@miba](#):
>
> I wonder why there are no error messages in the logs.

Don’t know, all very odd, trying to home in on what breaks it.

---

<div class="post-metadata">

**Author:** ![miba](https://community.openhab.org/user_avatar/community.openhab.org/miba/32/33506_2.png) [@miba](https://community.openhab.org/u/miba)\
**Post date:** [September 15, 2019, 11:45am UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/15 "2019-09-15T11:45:15Z")

</div>

> [@rossko57](#):
>
> should both result in Number objects, I think?

Yes, I think so, too.

> [@rossko57](#):
>
> Try  
> `val Number td=1.2345`

Still no difference…

I also tried this here:

```csv
logInfo("TEST", "Taupunkt_Differenz=" + Taupunkt_Differenz)
logInfo("TEST", "taupunkt_delta=" + taupunkt_delta)
var Number td=1.2345
logInfo("TEST", "td=" + td + " | taupunkt_delta=" + taupunkt_delta)
var String test1 = String::format("%.1f °C", td)
logInfo("TEST", "test1=" + test1)
var String test2 = String::format("%s", taupunkt_delta)
logInfo("TEST", "test2=" + test2)
td = taupunkt_delta
logInfo("TEST", "before test3")
var String test3 = String::format("%.1f °C", td)
logInfo("TEST", "test3=" + test3)
var String test4 = String::format("%.1f °C", taupunkt_delta)
logInfo("TEST", "test4=" + test4)

```

The log now ends with test #3:

```csv
2019-09-15 13:40:42.278 [INFO] [.eclipse.smarthome.model.script.TEST] - Taupunkt_Differenz=Taupunkt_Differenz (Type=NumberItem, State=0.7088823820515522, Label=Taupunktdifferenz Δtd, Category=humidity, Groups=[Weather, Temperature])
2019-09-15 13:40:42.293 [INFO] [.eclipse.smarthome.model.script.TEST] - taupunkt_delta=0.7088823820515522
2019-09-15 13:40:42.303 [INFO] [.eclipse.smarthome.model.script.TEST] - td=1.2345 | taupunkt_delta=0.7088823820515522
2019-09-15 13:40:42.311 [INFO] [.eclipse.smarthome.model.script.TEST] - test1=1,2 °C
2019-09-15 13:40:42.319 [INFO] [.eclipse.smarthome.model.script.TEST] - test2=0.7088823820515522
2019-09-15 13:40:42.326 [INFO] [.eclipse.smarthome.model.script.TEST] - before test3

```

There must be something wrong with the `taupunkt_delta`variable which the format statement does not like.

---

<div class="post-metadata">

**Author:** ![rossko57](https://community.openhab.org/user_avatar/community.openhab.org/rossko57/32/70263_2.png) [@rossko57](https://community.openhab.org/u/rossko57)\
**Post date:** [September 15, 2019, 12:15pm UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/16 "2019-09-15T12:15:41Z")

</div>

> [@miba](#):
>
> td = taupunkt\_delta

Longshot; try  
td = taupunkt\_delta + 1

---

<div class="post-metadata">

**Author:** ![miba](https://community.openhab.org/user_avatar/community.openhab.org/miba/32/33506_2.png) [@miba](https://community.openhab.org/u/miba)\
**Post date:** [September 15, 2019, 12:47pm UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/17 "2019-09-15T12:47:36Z")

</div>

> [@rossko57](#):
>
> Longshot; try  
> td = taupunkt\_delta + 1

Yes! For whatever reason, this did the trick! Now this approach works:

```csv
val Number taupunkt_delta = Taupunkt_Differenz.state as DecimalType + 0 // needed to avoid non-working String::format
var String test = String::format("%.1f °C", taupunkt_delta)
logInfo("myrule.rules", "test=" + test) // now it works!

```

Many thanks to @rossko57 & @vzorglub for helping me solve it!

Nevertheless I wonder why this happens because it worked before and it is still working in other rules…

---

<div class="post-metadata">

**Author:** ![vzorglub](https://community.openhab.org/user_avatar/community.openhab.org/vzorglub/32/17166_2.png) [@vzorglub](https://community.openhab.org/u/vzorglub)\
**Post date:** [September 15, 2019, 12:48pm UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/18 "2019-09-15T12:48:20Z")

</div>

Now that’s weird behaviour…

---

<div class="post-metadata">

**Author:** ![rossko57](https://community.openhab.org/user_avatar/community.openhab.org/rossko57/32/70263_2.png) [@rossko57](https://community.openhab.org/u/rossko57)\
**Post date:** [September 15, 2019, 12:57pm UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/19 "2019-09-15T12:57:55Z")

</div>

I was worrying about the leading zero maybe followed by comma actually, amazed it works with + 0  
Something to do with hidden baggage here. QuantityType issues shouldn’t be coming into play with a plain Number type Item, but it has that feel.

---

<div class="post-metadata">

**Author:** ![rossko57](https://community.openhab.org/user_avatar/community.openhab.org/rossko57/32/70263_2.png) [@rossko57](https://community.openhab.org/u/rossko57)\
**Post date:** [September 15, 2019, 11:54pm UTC](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948/20 "2019-09-15T23:54:04Z")

</div>

I had a play with this in OH2.4  
The good news is an error message appears -  
`f != org.eclipse.smarthome.core.library.types.DecimalType`

As we all probably expected, it’s to do with Java formatter not liking object type passed in.

But first, why did you not get the error message? Something odd about your install, like logging problems or locale, or is it a general OH2.5 issue?  
**Need an OH2.5 M3 user to try the following out please.**

Okay, so a demo rule to show the issue

```php
rule "format state"
when
   Item nm_test_temp changed
then
      // Item nm_test_state is defined: Number nm_test_temp "temp [%.1f °C]"
   val teststateA = (nm_test_temp.state as DecimalType).floatValue
   val teststateB = nm_test_temp.state as DecimalType
   logInfo("myrule.rules", "teststateA=" + teststateA.getClass)
   logInfo("myrule.rules", "teststateB=" + teststateB.getClass)
   var String test2 = String::format("%.1f °C", teststateA)
   logInfo("myrule.rules", "A formatted=" + test2)
   var String test3 = String::format("%.1f °C", teststateB)
   logInfo("myrule.rules", "B formatted=" + test3) // this line won't be reached!
end

```

openhab.log

```auto
2019-09-16 00:33:48.085 [INFO] [.smarthome.model.script.myrule.rules] - teststateA=class java.lang.Float
2019-09-16 00:33:48.086 [INFO] [.smarthome.model.script.myrule.rules] - teststateB=class org.eclipse.smarthome.core.library.types.DecimalType
2019-09-16 00:33:48.088 [INFO] [.smarthome.model.script.myrule.rules] - A formatted=15.5 °C
2019-09-16 00:33:48.090 [ERROR] [ntime.internal.engine.RuleEngineImpl] - Rule 'format state': f != org.eclipse.smarthome.core.library.types.DecimalType

```

So, a java **float** type (A) satisfies the java String formatter  
An openHAB/Eclipse **DecimalType** does not.

I think the error message is a bit backwards ; at first it seems like it is expecting a org.eclipse.smarthome.core.library.types.DecimalType, but I think the closer meaning is that “ **f** ” (as in `%.1f`) is complaining that it cannot work with DecimalType.

Remembering that `String::format` is “raw java” and not openHAB-ified, this is perhaps not that surprising after all.

> [@\[SOLVED\] String formatting in a rule of numbers](https://community.openhab.org/t/solved-string-formatting-in-a-rule-of-numbers/34332/2):
>
> Ahh I got it, I changed the definition of max from var Number max = ((heating\_morning\_maximum\_setpoint.state) as DecimalType) to var Number max = ((heating\_morning\_maximum\_setpoint.state) as DecimalType).floatValue and it worked as now it’s a float. I would have thought that DecimalType was already a float type

[Next page](https://community.openhab.org/t/solved-string-format-silently-fails-maybe-2-5-0-m3-issue/81948.md?page=2)