/*
* 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.type;
import com.facebook.presto.spi.type.ParameterKind;
import com.facebook.presto.spi.type.ParametricType;
import com.facebook.presto.spi.type.Type;
import com.facebook.presto.spi.type.TypeManager;
import com.facebook.presto.spi.type.TypeParameter;
import java.util.List;
import static com.facebook.presto.type.FunctionType.NAME;
import static com.google.common.base.Preconditions.checkArgument;
import static java.util.stream.Collectors.toList;
public final class FunctionParametricType
implements ParametricType
{
public static final FunctionParametricType FUNCTION = new FunctionParametricType();
private FunctionParametricType()
{
}
@Override
public String getName()
{
return NAME;
}
@Override
public Type createType(TypeManager typeManager, List<TypeParameter> parameters)
{
checkArgument(parameters.size() >= 1, "Function type must have at least one parameter, got %s", parameters);
checkArgument(
parameters.stream().allMatch(parameter -> parameter.getKind() == ParameterKind.TYPE),
"Expected only types as a parameters, got %s",
parameters);
List<Type> types = parameters.stream().map(parameter -> parameter.getType()).collect(toList());
return new FunctionType(types.subList(0, types.size() - 1), types.get(types.size() - 1));
}
}