/*
* 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 com.facebook.presto.operator.scalar;
import com.facebook.presto.metadata.BoundVariables;
import com.facebook.presto.metadata.FunctionRegistry;
import com.facebook.presto.metadata.SqlOperator;
import com.facebook.presto.spi.function.OperatorType;
import com.facebook.presto.spi.type.Type;
import com.facebook.presto.spi.type.TypeManager;
import com.google.common.collect.ImmutableList;
import java.lang.invoke.MethodHandle;
import java.lang.invoke.MethodHandles;
import static com.facebook.presto.metadata.Signature.typeVariable;
import static com.facebook.presto.spi.type.TypeSignature.parseTypeSignature;
import static com.google.common.base.Preconditions.checkArgument;
public class IdentityCast
extends SqlOperator
{
public static final IdentityCast IDENTITY_CAST = new IdentityCast();
protected IdentityCast()
{
super(OperatorType.CAST,
ImmutableList.of(typeVariable("T")),
ImmutableList.of(),
parseTypeSignature("T"),
ImmutableList.of(parseTypeSignature("T")));
}
@Override
public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
{
checkArgument(boundVariables.getTypeVariables().size() == 1, "Expected only one type");
Type type = boundVariables.getTypeVariable("T");
MethodHandle identity = MethodHandles.identity(type.getJavaType());
return new ScalarFunctionImplementation(false, ImmutableList.of(false), identity, isDeterministic());
}
}