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/*
* Copyright (c) 2020. https://rxmicro.io
*
* 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.rxmicro.common.util;
import io.rxmicro.common.CheckedWrapperException;
import java.util.Arrays;
import java.util.Optional;
import java.util.concurrent.CompletionException;
/**
* Utils class to work with exceptions.
*
* @author nedis
* @since 0.1
*/
public final class Exceptions {
/**
* Rethrows {@code throwable} if it is unchecked exception, otherwise throws a {@link CheckedWrapperException}
* instance with {@code throwable} as cause.
*
* @param throwable throwable that must be thrown
* @param any type
* @return nothing
* @see Error
* @see RuntimeException
* @see CheckedWrapperException
* @throws CheckedWrapperException if {@code throwable} is checked exception otherwise throws {@code throwable}
*/
public static T reThrow(final Throwable throwable) {
if (throwable instanceof RuntimeException) {
throw (RuntimeException) throwable;
} else if (throwable instanceof Error) {
throw (Error) throwable;
} else {
throw new CheckedWrapperException(throwable);
}
}
/**
* Verifies if {@code throwable} is instance of {@code exceptionType} type.
*
*
* In comparison with the {@code instanceof} operator this method extract real throwable from
* {@link CompletionException} and {@link CheckedWrapperException} ones.
*
* @param throwable tested throwable
* @param exceptionType expected exception type
* @return {@code true} if {@code throwable} is instance of {@code exceptionType} type
* @see CompletionException
* @see CheckedWrapperException
*/
public static boolean isInstanceOf(final Throwable throwable,
final Class exceptionType) {
if (throwable != null) {
if (exceptionType.isAssignableFrom(throwable.getClass())) {
return true;
}
if (throwable instanceof CompletionException) {
return getCause(throwable, CompletionException.class)
.map(th -> exceptionType.isAssignableFrom(th.getClass()))
.orElse(false);
}
if (throwable instanceof CheckedWrapperException) {
return getCause(throwable, CheckedWrapperException.class)
.map(th -> exceptionType.isAssignableFrom(th.getClass()))
.orElse(false);
}
}
return false;
}
/**
* Returns the {@link Optional} containing the cause of {@code throwable}.
*
*
* If the cause is one of provided {@code containerExceptionClasses} this methods inspects the cause deeper.
*
* @param throwable the tested throwable
* @param containerExceptionClasses the ignored container exception classes
* @return the {@link Optional} containing the cause of the {@code throwable}, if present
*/
@SafeVarargs
public static Optional getCause(final Throwable throwable,
final Class... containerExceptionClasses) {
Throwable result = throwable.getCause();
while (true) {
if (result == null) {
break;
}
final Throwable throwableInstance = result;
if (Arrays.stream(containerExceptionClasses).noneMatch(e -> e.isAssignableFrom(throwableInstance.getClass()))) {
break;
}
result = result.getCause();
}
return Optional.ofNullable(result);
}
/**
* Returns real throwable ignoring {@link CompletionException} and {@link CheckedWrapperException} containers.
*
* @param throwable tested throwable
* @return real throwable
* @see CompletionException
* @see CheckedWrapperException
*/
public static Throwable getRealThrowable(final Throwable throwable) {
return getCause(throwable, CompletionException.class, CheckedWrapperException.class).orElse(throwable);
}
private Exceptions() {
}
}