/*
* 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.FunctionKind;
import com.facebook.presto.metadata.FunctionRegistry;
import com.facebook.presto.metadata.Signature;
import com.facebook.presto.metadata.SqlScalarFunction;
import com.facebook.presto.spi.block.Block;
import com.facebook.presto.spi.type.Type;
import com.facebook.presto.spi.type.TypeManager;
import com.google.common.collect.ImmutableList;
import io.airlift.slice.Slice;
import java.lang.invoke.MethodHandle;
import static com.facebook.presto.metadata.Signature.typeVariable;
import static com.facebook.presto.spi.type.TypeSignature.parseTypeSignature;
import static com.facebook.presto.util.Reflection.methodHandle;
public class ElementToArrayConcatFunction
extends SqlScalarFunction
{
public static final ElementToArrayConcatFunction ELEMENT_TO_ARRAY_CONCAT_FUNCTION = new ElementToArrayConcatFunction();
private static final String FUNCTION_NAME = "concat";
private static final MethodHandle METHOD_HANDLE_BOOLEAN = methodHandle(ArrayConcatUtils.class, "prependElement", Type.class, boolean.class, Block.class);
private static final MethodHandle METHOD_HANDLE_LONG = methodHandle(ArrayConcatUtils.class, "prependElement", Type.class, long.class, Block.class);
private static final MethodHandle METHOD_HANDLE_DOUBLE = methodHandle(ArrayConcatUtils.class, "prependElement", Type.class, double.class, Block.class);
private static final MethodHandle METHOD_HANDLE_SLICE = methodHandle(ArrayConcatUtils.class, "prependElement", Type.class, Slice.class, Block.class);
private static final MethodHandle METHOD_HANDLE_OBJECT = methodHandle(ArrayConcatUtils.class, "prependElement", Type.class, Object.class, Block.class);
public ElementToArrayConcatFunction()
{
super(new Signature(
FUNCTION_NAME,
FunctionKind.SCALAR,
ImmutableList.of(typeVariable("E")),
ImmutableList.of(),
parseTypeSignature("array(E)"),
ImmutableList.of(parseTypeSignature("E"), parseTypeSignature("array(E)")),
false));
}
@Override
public boolean isHidden()
{
return false;
}
@Override
public boolean isDeterministic()
{
return true;
}
@Override
public String getDescription()
{
return "Concatenates an element to an array";
}
@Override
public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, TypeManager typeManager, FunctionRegistry functionRegistry)
{
Type type = boundVariables.getTypeVariable("E");
MethodHandle methodHandle;
if (type.getJavaType() == boolean.class) {
methodHandle = METHOD_HANDLE_BOOLEAN;
}
else if (type.getJavaType() == long.class) {
methodHandle = METHOD_HANDLE_LONG;
}
else if (type.getJavaType() == double.class) {
methodHandle = METHOD_HANDLE_DOUBLE;
}
else if (type.getJavaType() == Slice.class) {
methodHandle = METHOD_HANDLE_SLICE;
}
else {
methodHandle = METHOD_HANDLE_OBJECT;
}
methodHandle = methodHandle.bindTo(type);
return new ScalarFunctionImplementation(false, ImmutableList.of(false, false), methodHandle, isDeterministic());
}
}