GenericLongFunction.java
/*
* 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;
import com.facebook.presto.common.QualifiedObjectName;
import com.facebook.presto.metadata.BoundVariables;
import com.facebook.presto.metadata.FunctionAndTypeManager;
import com.facebook.presto.metadata.SqlScalarFunction;
import com.facebook.presto.operator.scalar.BuiltInScalarFunctionImplementation;
import com.facebook.presto.spi.function.Signature;
import com.facebook.presto.spi.function.SqlFunctionVisibility;
import com.google.common.collect.ImmutableList;
import java.lang.invoke.MethodHandle;
import java.util.function.LongUnaryOperator;
import static com.facebook.presto.common.type.StandardTypes.BIGINT;
import static com.facebook.presto.common.type.TypeSignature.parseTypeSignature;
import static com.facebook.presto.metadata.BuiltInTypeAndFunctionNamespaceManager.JAVA_BUILTIN_NAMESPACE;
import static com.facebook.presto.operator.scalar.ScalarFunctionImplementationChoice.ArgumentProperty.valueTypeArgumentProperty;
import static com.facebook.presto.operator.scalar.ScalarFunctionImplementationChoice.NullConvention.RETURN_NULL_ON_NULL;
import static com.facebook.presto.spi.function.FunctionKind.SCALAR;
import static com.facebook.presto.spi.function.SqlFunctionVisibility.HIDDEN;
import static com.facebook.presto.util.Reflection.methodHandle;
import static java.util.Collections.emptyList;
import static java.util.Collections.singletonList;
import static java.util.Objects.requireNonNull;
public final class GenericLongFunction
extends SqlScalarFunction
{
private static final MethodHandle METHOD_HANDLE = methodHandle(GenericLongFunction.class, "apply", LongUnaryOperator.class, long.class);
private final LongUnaryOperator longUnaryOperator;
GenericLongFunction(String suffix, LongUnaryOperator longUnaryOperator)
{
super(new Signature(QualifiedObjectName.valueOf(JAVA_BUILTIN_NAMESPACE, "generic_long_" + requireNonNull(suffix, "suffix is null")), SCALAR,
emptyList(), emptyList(), parseTypeSignature(BIGINT), singletonList(parseTypeSignature(BIGINT)), false));
this.longUnaryOperator = longUnaryOperator;
}
@Override
public final SqlFunctionVisibility getVisibility()
{
return HIDDEN;
}
@Override
public boolean isDeterministic()
{
return true;
}
@Override
public String getDescription()
{
return "generic long function for test";
}
@Override
public BuiltInScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, FunctionAndTypeManager functionAndTypeManager)
{
MethodHandle methodHandle = METHOD_HANDLE.bindTo(longUnaryOperator);
return new BuiltInScalarFunctionImplementation(false, ImmutableList.of(valueTypeArgumentProperty(RETURN_NULL_ON_NULL)), methodHandle);
}
public static long apply(LongUnaryOperator longUnaryOperator, long value)
{
return longUnaryOperator.applyAsLong(value);
}
}