buckelieg.fn.db.TryAction Maven / Gradle / Ivy
/*
* Copyright 2016- Anatoly Kutyakov
*
* 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 buckelieg.fn.db;
import static java.util.Objects.requireNonNull;
/**
* An arbitrary action that might throw an exception
*
* @param exception type
*/
@SuppressWarnings("unchecked")
@FunctionalInterface
public interface TryAction {
/**
* Performs an action with possible exceptional result
*
* @throws E an exception
*/
void doTry() throws E;
/**
* Returns reference of lambda expression.
*
* @param tryAction an action
* @return {@link TryAction} reference
* @throws NullPointerException if tryAction is null
*/
static TryAction of(TryAction tryAction) {
return requireNonNull(tryAction);
}
/**
* Returns a composed {@code TryAction} that performs, in sequence, this
* operation is followed by the {@code after} operation. If performing either
* operation throws an exception, then corresponding exception is thrown.
* If performing this operation throws an exception,
* the {@code after} operation will not be performed.
*
* @param after the operation to perform after this operation
* @return a composed {@code TryAction} that performs in sequence this
* operation followed by the {@code after} operation
* @throws E an exception
* @throws NullPointerException if {@code after} is null
*/
default TryAction andThen(TryAction after) throws E {
try {
return () -> {
doTry();
requireNonNull(after).doTry();
};
} catch (Throwable t) {
throw (E) t;
}
}
/**
* Returns a composed {@code TryAction} that performs, in sequence, this
* operation is preceded by the {@code before} operation. If performing either
* operation throws an exception, then corresponding exception is thrown.
* If performing this operation throws an exception,
* the {@code before} operation will not be performed.
*
* @param before the operation to perform before this operation
* @return a composed {@code TryAction} that performs in sequence this
* operation followed by the {@code before} operation
* @throws E an exception
* @throws NullPointerException if {@code before} is null
*/
default TryAction compose(TryAction before) throws E {
try {
return () -> {
requireNonNull(before).doTry();
doTry();
};
} catch (Throwable t) {
throw (E) t;
}
}
}