io.trino.operator.scalar.IdentityCast Maven / Gradle / Ivy
/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.trino.operator.scalar;
import com.google.common.collect.ImmutableList;
import io.trino.metadata.SqlScalarFunction;
import io.trino.spi.function.BoundSignature;
import io.trino.spi.function.FunctionMetadata;
import io.trino.spi.function.Signature;
import io.trino.spi.type.Type;
import io.trino.spi.type.TypeSignature;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import static io.trino.spi.function.InvocationConvention.InvocationArgumentConvention.NEVER_NULL;
import static io.trino.spi.function.InvocationConvention.InvocationReturnConvention.FAIL_ON_NULL;
import static io.trino.spi.function.OperatorType.CAST;
public class IdentityCast
extends SqlScalarFunction
{
public static final IdentityCast IDENTITY_CAST = new IdentityCast();
private IdentityCast()
{
super(FunctionMetadata.operatorBuilder(CAST)
.signature(Signature.builder()
.typeVariable("T")
.returnType(new TypeSignature("T"))
.argumentType(new TypeSignature("T"))
.build())
.build());
}
@Override
protected SpecializedSqlScalarFunction specialize(BoundSignature boundSignature)
{
Type type = boundSignature.getReturnType();
MethodHandle identity = MethodHandles.identity(type.getJavaType());
return new ChoicesSpecializedSqlScalarFunction(
boundSignature,
FAIL_ON_NULL,
ImmutableList.of(NEVER_NULL),
identity);
}
}