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Functional interfaces and utility class used to express computations on
Speedment entities.
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/*
*
* Copyright (c) 2006-2020, Speedment, Inc. All Rights Reserved.
*
* 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.speedment.runtime.compute.trait;
import com.speedment.runtime.compute.ToDouble;
import com.speedment.runtime.compute.ToDoubleNullable;
/**
* Trait for nullable expressions that can be mapped to a new expression of the
* same type by supplying a mapping function. If the value is present in the
* original expression, then it will be present in the new one as well. If the
* result of the original expression is {@code null}, then the new expression
* will evaluate to {@code null} also.
*
* @param the input entity type
* @param the functional interface used for mapping values
*
* @author Emil Forslund
* @since 3.1.0
*/
public interface HasMapToDoubleIfPresent {
/**
* Maps the result of this expression into a {@code double} by passing it to
* the specified {@code mapper}, producing a new expression that implements
* {@link ToDouble}. If this expression would have evaluated to
* {@code null}, then the new expression will as well.
*
* @param mapper the mapper to use on the result of this expression
* @return the new mapped expression
*/
ToDoubleNullable mapToDoubleIfPresent(MAPPER mapper);
}