org.specrunner.util.ExceptionUtil Maven / Gradle / Ivy

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/*
    SpecRunner - Acceptance Test Driven Development Tool
    Copyright (C) 2011-2013  Thiago Santos

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see 
 */
package org.specrunner.util;

import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;

import org.specrunner.SpecRunnerException;

/**
 * Exception utilities.
 * 
 * @author Thiago Santos
 * 
 */
public final class ExceptionUtil {

    /**
     * Hidden constructor.
     */
    private ExceptionUtil() {
    }

    /**
     * Dump exception trace to a string.
     * 
     * @param exception
     *            The exception.
     * @return The error String representation.
     * @throws IOException
     *             On dump errors.
     */
    public static String toString(Throwable exception) throws IOException {
        StringWriter sw = new StringWriter();
        PrintWriter pw = new PrintWriter(sw);
        exception.printStackTrace(pw);
        pw.close();
        String result = sw.toString();
        sw.close();
        return result;
    }

    /**
     * Unwrap SpecRunner subclasses exception to find root cause. If none is
     * found, the most specific exception is returned.
     * 
     * @param error
     *            The error.
     * @return The unwrapped exception.
     */
    public static Throwable unwrapException(Throwable error) {
        while (error instanceof SpecRunnerException) {
            if (error.getCause() != null) {
                error = error.getCause();
            } else {
                break;
            }
        }
        return error;
    }
}