/**
* Copyright (c) 2016-present, RxJava Contributors.
*
* 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 io.reactivex.internal.fuseable;
import java.util.concurrent.Callable;
/**
* A marker interface indicating that a scalar, constant value
* is held by the implementing reactive type which can be
* safely extracted during assembly time can be used for
* optimization.
* <p>
* Implementors of {@link #call()} should not throw any exception.
* <p>
* Design note: the interface extends {@link Callable} because if a scalar
* is safe to extract during assembly time, it is also safe to extract at
* subscription time or later. This allows optimizations to deal with such
* single-element sources uniformly.
* <p>
* @param <T> the scalar value type held by the implementing reactive type
*/
public interface ScalarCallable<T> extends Callable<T> {
// overridden to remove the throws Exception
@Override
T call();
}