OptionalBuilder.java example

Explorer
jdbi-master
/*
 * 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 org.jdbi.v3.core.collector;

import java.util.Optional;

class OptionalBuilder<T> {
    private Optional<T> optional = Optional.empty();

    public void set(T value) {
        if (optional.isPresent()) {
            throw new IllegalStateException(
                    String.format("Multiple values for Optional type: ['%s','%s',...]",
                            optional.get(),
                            value));
        }
        optional = Optional.ofNullable(value);
    }

    public Optional<T> build() {
        return optional;
    }
}