/*
* Copyright 2002-2017 the original author or authors.
*
* 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 org.springframework.core;
/**
* Helper class for implementing exception classes which are capable of
* holding nested exceptions. Necessary because we can't share a base
* class among different exception types.
*
* <p>Mainly for use within the framework.
*
* @author Juergen Hoeller
* @since 2.0
* @see NestedRuntimeException
* @see NestedCheckedException
* @see NestedIOException
* @see org.springframework.web.util.NestedServletException
*/
public abstract class NestedExceptionUtils {
/**
* Build a message for the given base message and root cause.
* @param message the base message
* @param cause the root cause
* @return the full exception message
*/
public static String buildMessage(String message, Throwable cause) {
if (cause == null) {
return message;
}
StringBuilder sb = new StringBuilder(64);
if (message != null) {
sb.append(message).append("; ");
}
sb.append("nested exception is ").append(cause);
return sb.toString();
}
/**
* Retrieve the innermost cause of the given exception, if any.
* @param original the original exception to introspect
* @return the innermost exception, or {@code null} if none
* @since 4.3.9
*/
public static Throwable getRootCause(Throwable original) {
if (original == null) {
return null;
}
Throwable rootCause = null;
Throwable cause = original.getCause();
while (cause != null && cause != rootCause) {
rootCause = cause;
cause = cause.getCause();
}
return rootCause;
}
/**
* Retrieve the most specific cause of the given exception, that is,
* either the innermost cause (root cause) or the exception itself.
* <p>Differs from {@link #getRootCause} in that it falls back
* to the original exception if there is no root cause.
* @param original the original exception to introspect
* @return the most specific cause (never {@code null})
* @since 4.3.9
*/
public static Throwable getMostSpecificCause(Throwable original) {
Throwable rootCause = getRootCause(original);
return (rootCause != null ? rootCause : original);
}
}