javascalautils.Failure 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.Predicate;
import java.util.function.Supplier;
import static javascalautils.TryCompanion.Success;
/**
* Represents the failure implementation of {@link Try}.
* Acts as a carrier for the result/throwable of a unsuccessful computation.
* For examples on usage refer to the documentation for {@link Try}.
*
* @author Peter Nerg
* @since 1.0
* @param The type of the exception represented by this instance
*/
public final class Failure extends EmptyContainer implements Try, Serializable {
private static final long serialVersionUID = -3153874073796965428L;
private final Throwable throwable;
/**
* Creates a Failure for the provided Throwable.
* Null values are not allowed since a 'failure' needs a reason.
*
* @param throwable The throwable
* @since 1.0
*/
public Failure(Throwable throwable) {
this.throwable = Validator.requireNonNull(throwable, "Null values are not allowed for Failure");
}
/**
* Always returns false.
*
* @since 1.0
*/
@Override
public boolean isSuccess() {
return false;
}
/**
* Always returns the value provided by the supplier.
* As per definition this is a failure without any data to return.
*
* @since 1.0
*/
@Override
public T getOrElse(Supplier supplier) {
return supplier.get();
}
/**
* Always returns the value provided by the supplier.
* As per definition this is a failure without any data to return.
*
* @since 1.0
*/
@Override
public Try orElse(Supplier> supplier) {
return supplier.get();
}
/**
* Always throws the {@link Throwable} this instance represents.
* As per definition this is a failure without any data to return.
*
* @since 1.0
*/
@Override
public T get() throws Throwable {
throw throwable;
}
/**
* Returns a {@link Success} with the {@link Throwable} this instance represents.
*
* @since 1.0
*/
@Override
public Try failed() {
return Success(throwable);
}
/**
* Always returns this.
* As per definition this is a failure without any data to map.
*
* @since 1.0
*/
@SuppressWarnings("unchecked")
@Override
public Try map(ThrowableFunction1 function) {
return (Try) this;
}
/**
* Always returns this.
* As per definition this is a failure without any data to map.
*
* @since 1.2
*/
@Override
public Try flatMap(ThrowableFunction1> function) {
return map(null);
}
/**
* Always returns this.
* As per definition this is a failure without any data to filter.
*
* @since 1.4
*/
@Override
public Try filter(Predicate predicate) {
return this;
}
/**
* Applies the provided function to the Throwable of this {@link Failure} and returns a {@link
* Success} with the result.
*
* @since 1.4
*/
@Override
public Try recover(ThrowableFunction1 function) {
return recoverWith(t -> Success(function.apply(t)));
}
/**
* Applies the provided function to the Throwable of this {@link Failure} and returns the result.
*
* @since 1.4
*/
@Override
public Try recoverWith(ThrowableFunction1> function) {
try {
return function.apply(throwable);
} catch (Throwable t) {
return new Failure<>(t);
}
}
/**
* Returns a String representation of the instance.
*
* @since 1.0
*/
@Override
public String toString() {
return String.format("Failure(%s)", throwable.getMessage());
}
}