001/**
002 * Logback: the reliable, generic, fast and flexible logging framework.
003 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
004 *
005 * This program and the accompanying materials are dual-licensed under
006 * either the terms of the Eclipse Public License v1.0 as published by
007 * the Eclipse Foundation
008 *
009 *   or (per the licensee's choosing)
010 *
011 * under the terms of the GNU Lesser General Public License version 2.1
012 * as published by the Free Software Foundation.
013 */
014package ch.qos.logback.classic.spi;
015
016public class EventArgUtil {
017
018    public static final Throwable extractThrowable(Object[] argArray) {
019        if (argArray == null || argArray.length == 0) {
020            return null;
021        }
022
023        final Object lastEntry = argArray[argArray.length - 1];
024        if (lastEntry instanceof Throwable) {
025            return (Throwable) lastEntry;
026        }
027        return null;
028    }
029
030    /**
031     * This method should be called only if {@link #successfulExtraction(Throwable)}
032     * returns true.
033     *
034     * @param argArray
035     * @return
036     */
037    public static Object[] trimmedCopy(Object[] argArray) {
038        if (argArray == null || argArray.length == 0) {
039            throw new IllegalStateException("non-sensical empty or null argument array");
040        }
041        final int trimemdLen = argArray.length - 1;
042        Object[] trimmed = new Object[trimemdLen];
043        System.arraycopy(argArray, 0, trimmed, 0, trimemdLen);
044        return trimmed;
045    }
046
047    public static Object[] arrangeArguments(Object[] argArray) {
048        return argArray;
049    }
050
051    public static boolean successfulExtraction(Throwable throwable) {
052        return throwable != null;
053    }
054}