org.sonar.java.exceptions.ThrowableUtils Maven / Gradle / Ivy

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/*
 * SonarQube Java
 * Copyright (C) 2012-2023 SonarSource SA
 * mailto:info AT sonarsource DOT com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 3 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */
package org.sonar.java.exceptions;

public class ThrowableUtils {
  
  private ThrowableUtils() {
  }

  /* This method uses a standard 2 pointers algorithm to detect whether there is a cycle in a chain of exception causes */
  public static Throwable getRootCause(Throwable throwable) {
    Throwable slowPointer = throwable;

    Throwable cause;
    Throwable t = throwable;
    for(boolean advanceSlowPointer = false; (cause = t.getCause()) != null; advanceSlowPointer = !advanceSlowPointer) {
      t = cause;
      if (cause == slowPointer) {
        throw new IllegalArgumentException("Loop in causal chain detected.", cause);
      }

      if (advanceSlowPointer) {
        slowPointer = slowPointer.getCause();
      }
    }
    return t;
  }
}