org.apache.flink.api.java.functions

Class SelectByMaxFunction<T extends Tuple>

java.lang.Object

org.apache.flink.api.java.functions.SelectByMaxFunction<T>

All Implemented Interfaces:

Serializable, org.apache.flink.api.common.functions.Function, org.apache.flink.api.common.functions.ReduceFunction<T>

public class SelectByMaxFunction<T extends Tuple>
extends Object
implements org.apache.flink.api.common.functions.ReduceFunction<T>

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
SelectByMaxFunction(TupleTypeInfo<T> type, int... fields) Constructor which is overwriting the default constructor.

Method Summary

Modifier and Type	Method and Description
T	reduce(T value1, T value2) Reduce implementation, returns bigger tuple or value1 if both tuples are equal.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SelectByMaxFunction

public SelectByMaxFunction(TupleTypeInfo<T> type,
                           int... fields)

Constructor which is overwriting the default constructor.

Parameters:

type - Types of tuple whether to check if given fields are key types.

fields - Array of integers which are used as key for comparison. The order of indexes is regarded in the reduce function. First index has highest priority and last index has least priority.

Method Detail

reduce

public T reduce(T value1,
                T value2)
         throws Exception

Reduce implementation, returns bigger tuple or value1 if both tuples are equal. Comparison highly depends on the order and amount of fields chosen as indices. All given fields (at construction time) are checked in the same order as defined (at construction time). If both tuples are equal in one index, the next index is compared. Or if no next index is available value1 is returned. The tuple which has a bigger value at one index will be returned.

Specified by:

reduce in interface org.apache.flink.api.common.functions.ReduceFunction<T extends Tuple>

Throws:

Exception