Ted Dunning created FLINK-4793:
----------------------------------
Summary: 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
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.
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