org.apache.hadoop.hive.ql.exec.UDFMethodResolver Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
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*/
package org.apache.hadoop.hive.ql.exec;
import java.lang.reflect.Method;
import java.util.List;
import org.apache.hadoop.hive.serde2.typeinfo.TypeInfo;
/**
* The UDF Method resolver interface. A user can plugin a resolver to their UDF
* by implementing the functions in this interface. Note that the resolver is
* stored in the UDF class as an instance variable. We did not use a static
* variable because many resolvers maintain the class of the enclosing UDF as
* state and are called from a base class e.g. UDFBaseCompare. This makes it
* very easy to write UDFs that want to do resolution similar to the comparison
* operators. Such UDFs just need to extend UDFBaseCompare and do not have to
* care about the UDFMethodResolver interface. Same is true for UDFs that want
* to do resolution similar to that done by the numeric operators. Such UDFs
* simply have to extend UDFBaseNumericOp class. For the default resolution the
* UDF implementation simply needs to extend the UDF class.
*/
@Deprecated
public interface UDFMethodResolver {
/**
* Gets the evaluate method for the UDF given the parameter types.
*
* @param argClasses
* The list of the argument types that need to matched with the
* evaluate function signature.
*/
Method getEvalMethod(List argClasses) throws UDFArgumentException;
}