Fabian Hueske created FLINK-1906:
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Summary: Add tip to work around plain Tuple return type of project
operator
Key: FLINK-1906
URL: https://issues.apache.org/jira/browse/FLINK-1906
Project: Flink
Issue Type: Improvement
Components: Documentation
Affects Versions: 0.9
Reporter: Fabian Hueske
Priority: Minor
The Java compiler is not able to infer the return type of the {{project}}
operator and defaults to {{Tuple}}. This can cause problems if another operator
is immediately called on the result of a {{project}} operator such as:
{code}
DataSet<Tuple5<String,String,String,String,String>> ds = ....
DataSet<Tuple1<String>> ds2 = ds.project(0).distinct(0);
{code}
This problem can be overcome by hinting the return type of {{project}} like
this:
{code}
DataSet<Tuple1<String>> ds2 = ds.<Tuple1<String>project(0).distinct(0);
{code}
We should add this description to the documentation of the project operator.
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