Class EmptyRowDataKeySelector
- java.lang.Object
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- org.apache.flink.table.runtime.keyselector.EmptyRowDataKeySelector
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- All Implemented Interfaces:
Serializable
,Function
,KeySelector<RowData,RowData>
,ResultTypeQueryable<RowData>
,RowDataKeySelector
public class EmptyRowDataKeySelector extends Object implements RowDataKeySelector
A utility class which key is always empty no matter what the input row is.- See Also:
- Serialized Form
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Field Summary
Fields Modifier and Type Field Description static EmptyRowDataKeySelector
INSTANCE
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Constructor Summary
Constructors Constructor Description EmptyRowDataKeySelector()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description RowData
getKey(RowData value)
User-defined function that deterministically extracts the key from an object.InternalTypeInfo<RowData>
getProducedType()
Gets the data type (as aTypeInformation
) produced by this function or input format.
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Field Detail
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INSTANCE
public static final EmptyRowDataKeySelector INSTANCE
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Method Detail
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getKey
public RowData getKey(RowData value) throws Exception
Description copied from interface:KeySelector
User-defined function that deterministically extracts the key from an object.For example for a class:
public class Word { String word; int count; }
The key extractor could return the word as a key to group all Word objects by the String they contain.
The code would look like this
public String getKey(Word w) { return w.word; }
- Specified by:
getKey
in interfaceKeySelector<RowData,RowData>
- Parameters:
value
- The object to get the key from.- Returns:
- The extracted key.
- Throws:
Exception
- Throwing an exception will cause the execution of the respective task to fail, and trigger recovery or cancellation of the program.
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getProducedType
public InternalTypeInfo<RowData> getProducedType()
Description copied from interface:ResultTypeQueryable
Gets the data type (as aTypeInformation
) produced by this function or input format.- Specified by:
getProducedType
in interfaceResultTypeQueryable<RowData>
- Specified by:
getProducedType
in interfaceRowDataKeySelector
- Returns:
- The data type produced by this function or input format.
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