/*
 * #%L
 * SciJava Common shared library for SciJava software.
 * %%
 * Copyright (C) 2009 - 2017 Board of Regents of the University of
 * Wisconsin-Madison, Broad Institute of MIT and Harvard, and Max Planck
 * Institute of Molecular Cell Biology and Genetics.
 * %%
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * #L%
 */

package org.scijava.log;

/**
 * Utility class for getting the calling class of a method.
 *
 * @author Matthias Arzt
 */

@IgnoreAsCallingClass
public final class CallingClassUtils {

	private CallingClassUtils() {
		// prevent instantiation of utility class
	}

	/**
	 * Inspects the stack trace to return the class that calls this method, but
	 * ignores every class annotated with @IgnoreAsCallingClass.
	 *
	 * @throws IllegalStateException if every method on the stack, is in a class
	 *           annotated with @IgnoreAsCallingClass.
	 */
	public static Class<?> getCallingClass() {
		try {
			StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();
			for (int i = 1; i < stackTrace.length - 1; i++) {
				Class<?> clazz = Class.forName(stackTrace[i].getClassName());
				if (!clazz.isAnnotationPresent(IgnoreAsCallingClass.class))
					return clazz;
			}
		}
		catch (ClassNotFoundException ignore) {}
		throw new IllegalStateException();
	}

}
