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/**
* The MIT License (MIT)
*
* Copyright (c) 2017-2018 Yegor Bugayenko
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
package org.cactoos;
import org.cactoos.scalar.IoCheckedScalar;
import org.cactoos.scalar.StickyScalar;
import org.cactoos.scalar.UncheckedScalar;
/**
* Scalar.
*
* If you don't want to have any checked exceptions being thrown
* out of your {@link Scalar}, you can use
* {@link UncheckedScalar} decorator. Also
* you may try {@link IoCheckedScalar}.
*
* If you want to cache the result of the {@link Scalar} and
* make sure it doesn't calculate anything twice, you can use
* {@link StickyScalar} decorator.
*
* There is no thread-safety guarantee.
*
* @author Yegor Bugayenko ([email protected])
* @version $Id: e78d65cac2503477907e438df4db1b893de1a730 $
* @param Type of result
* @see StickyScalar
* @see UncheckedScalar
* @see IoCheckedScalar
* @since 0.1
*/
public interface Scalar {
/**
* Convert it to the value.
* @return The value
* @throws Exception If fails
*/
T value() throws Exception;
/**
* Scalar check for no nulls.
*
* @author Fabricio Cabral ([email protected])
* @version $Id: e78d65cac2503477907e438df4db1b893de1a730 $
* @param Type of result
* @since 0.11
*/
final class NoNulls implements Scalar {
/**
* The scalar.
*/
private final Scalar origin;
/**
* Ctor.
* @param sclr The scalar
*/
public NoNulls(final Scalar sclr) {
this.origin = sclr;
}
@Override
public T value() throws Exception {
if (this.origin == null) {
throw new IllegalArgumentException(
"NULL instead of a valid scalar"
);
}
final T value = this.origin.value();
if (value == null) {
throw new IllegalStateException(
"NULL instead of a valid value"
);
}
return value;
}
}
}