HostUDFWrapper#

public abstract class HostUDFWrapper#

A wrapper around native host UDF aggregations.

This class is used to create the native handle of a host UDF aggregation and is used as a proxy object to compute hash code and compare two host UDF aggregations for equality.

A new host UDF aggregation implementation must extend this class and override the computeHashCode and isEqual methods for such purposes.

Method Summary

`closeUDFInstance(long hostUDFInstance)`	Close the derived UDF instance created by createUDFInstance.
`computeHashCode()`
`createUDFInstance()`	Create a derived host UDF native instance.
`equals(Object obj)`
`hashCode()`
`isEqual(Object obj)`

Methods

public abstract long createUDFInstance()#

Create a derived host UDF native instance.

The instance created by this function MUST be closed by closeUDFInstance

Typical usage, refer to Aggregation.java:

long udf = 0;
try {
    udf = wrapper.createUDFInstance();
    return Aggregation.createHostUDFAgg(udf);
} finally {
    // a new UDF is cloned in `createHostUDFAgg`, here should close the UDF instance.
    if (udf != 0) {
        HostUDFWrapper.closeUDFInstance(udf);
    }
}

public abstract int computeHashCode()#

public int hashCode()#

public abstract boolean isEqual(Object obj)#

public boolean equals(Object obj)#

Static Methods

public static void closeUDFInstance(long hostUDFInstance)#

Close the derived UDF instance created by createUDFInstance.

Parameters:: hostUDFInstance – the UDF instance