[ 
https://issues.apache.org/jira/browse/FLINK-4793?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15564985#comment-15564985
 ] 

Timo Walther commented on FLINK-4793:
-------------------------------------

I will look into this.

> Using a local method with :: notation in Java 8 causes index out of bounds
> --------------------------------------------------------------------------
>
>                 Key: FLINK-4793
>                 URL: https://issues.apache.org/jira/browse/FLINK-4793
>             Project: Flink
>          Issue Type: Bug
>            Reporter: Ted Dunning
>            Assignee: Timo Walther
>
> I tried to use the toString method on an object as a map function:
> {code}
>                 .<String>map(Trade::toString)
> {code}
> This caused an index out of bounds error:
> {code}
> java.lang.ArrayIndexOutOfBoundsException: -1
>       at 
> org.apache.flink.api.java.typeutils.TypeExtractor.getUnaryOperatorReturnType(TypeExtractor.java:351)
>       at 
> org.apache.flink.api.java.typeutils.TypeExtractor.getUnaryOperatorReturnType(TypeExtractor.java:305)
>       at 
> org.apache.flink.api.java.typeutils.TypeExtractor.getMapReturnTypes(TypeExtractor.java:120)
>       at 
> org.apache.flink.streaming.api.datastream.DataStream.map(DataStream.java:506)
>       at 
> com.mapr.aggregate.AggregateTest.testAggregateTrades(AggregateTest.java:81)
>       at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>       at 
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
>       at 
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
>       at 
> org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
>       at 
> org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
>       at 
> org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
>       at 
> org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
>       at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
>       at 
> org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
>       at 
> org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
>       at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
>       at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
>       at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
>       at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
>       at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
>       at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
>       at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
>       at 
> com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:68)
> {code}
> On the other hand, if I use a public static method, like this:
> {code}
>                 .<Trade>map(Trade::fromString)
> {code}
> All is good. fromString and toString are defined like this:
> {code}
>     public static Trade fromString(String s) throws IOException {
>         return mapper.readValue(s, Trade.class);
>     }
>     @Override
>     public String toString() {
>         return String.format("{\"%s\", %d, %d, %.2f}", symbol, time, volume, 
> price);
>     }
> {code}
> This might be a viable restriction on what functions I can use, but there 
> certainly should be a better error message, if so.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Reply via email to