content: /*
   * 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
   *
   *      https://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 com.alibaba.nacos.common.packagescan.util;
  
  /**
   * Copy from https://github.com/spring-projects/spring-framework.git, with less modifications
   * 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
   * @see NestedIoException
   * @since 2.0
   */
  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);
      }
  
  }
  