javascalautils.RightProjection Maven / Gradle / Ivy
/**
* Copyright 2015 Peter Nerg
*
* 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 javascalautils;
import java.io.Serializable;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.function.Supplier;
import static javascalautils.EitherCompanion.Right;
/**
* This is a right-biased wrapper for an instance of {@link Either}.
*
* @author Peter Nerg
* @since 1.1
*/
public class RightProjection extends Projection implements Serializable {
private static final long serialVersionUID = 4251047373391313192L;
private final Either either;
/**
* Creates an instance of the projection.
*
* @param either
* The instance to wrap.
* @since 1.1
*/
RightProjection(Either either) {
this.either = either;
}
/**
* Returns false if {@link Left} or returns the result of applying the predicate to the {@link Right} value.
*
* @param predicate
* The predicate to apply
* @return If this is a {@link Right} and the predicate matches the value
* @since 1.1
*/
public boolean exists(Predicate predicate) {
return either.isRight() && predicate.test(orNull());
}
/**
* Returns the value if this is a {@link Right} else the value provided by the supplier.
*
* @param supplier
* The supplier
* @return The value
* @since 1.1
*/
@Override
public R getOrElse(Supplier supplier) {
return either.fold(v -> supplier.get(), v -> v);
}
/**
* Returns a {@link Some} wrapping the {@link Either} if it's a {@link Right} and the value of the {@link Right} matches the predicate, else {@link None} .
*
* @param predicate
* The predicate to apply
* @return The resulting Option of the filter operation
* @since 1.1
*/
public Option> filter(Predicate predicate) {
return Option.apply(exists(predicate) ? either : null);
}
/**
* Returns true if {@link Left} or returns the result of applying the predicate to the {@link Right} value.
*
* @param predicate
* The predicate to apply
* @return If it is a match
* @since 1.1
*/
public boolean forAll(Predicate predicate) {
return !either.isRight() || predicate.test(orNull());
}
/**
* If this projection contains a {@link Right} then a new {@link Right} is returned containing the value from the original {@link Right} mapped via the
* provided function, else the contained Either is returned as is.
*
* @param
* The type to return as the new {@link Right}
* @param function
* The function
* @return Mapped Either
* @since 1.1
*/
@SuppressWarnings("unchecked")
public Either map(Function function) {
return either.isRight() ? Right(function.apply(get())) : (Either) either;
}
/**
* If this projection contains a {@link Right} then a new {@link Right} is returned containing the value from the original {@link Right} mapped via the
* provided function, else the contained Either is returned as is.
*
* @param
* The type to return as the new {@link Right}
* @param function
* The function
* @return Mapped Either
* @since 1.2
*/
@SuppressWarnings("unchecked")
public Either flatMap(Function> function) {
return either.isRight() ? function.apply(get()) : (Either) either;
}
}