Util.java

/**************************************************************************************
 * Copyright (c) Jonas Bon�r, Alexandre Vasseur. All rights reserved.                 *
 * http://aspectwerkz.codehaus.org                                                    *
 * ---------------------------------------------------------------------------------- *
 * The software in this package is published under the terms of the LGPL license      *
 * a copy of which has been included with this distribution in the license.txt file.  *
 **************************************************************************************/
package org.codehaus.aspectwerkz.util;

import org.codehaus.aspectwerkz.reflect.ReflectionInfo;

/**
 * Utility methods and constants used in the AspectWerkz system.
 *
 * @author <a href="mailto:jboner@codehaus.org">Jonas Bon�r </a>
 */
public final class Util {
    public static final Integer INTEGER_DEFAULT_VALUE = new Integer(0);

    public static final Float FLOAT_DEFAULT_VALUE = new Float(0.0f);

    public static final Double DOUBLE_DEFAULT_VALUE = new Double(0.0d);

    public static final Long LONG_DEFAULT_VALUE = new Long(0L);

    public static final Boolean BOOLEAN_DEFAULT_VALUE = new Boolean(false);

    public static final Character CHARACTER_DEFAULT_VALUE = new Character('\u0000');

    public static final Short SHORT_DEFAULT_VALUE;

    public static final Byte BYTE_DEFAULT_VALUE;

    static {
        byte b = 0;
        BYTE_DEFAULT_VALUE = new Byte(b);
        short s = 0;
        SHORT_DEFAULT_VALUE = new Short(s);
    }

    /**
     * Calculates the hash for the class name and the meta-data.
     *
     * @param className the class name
     * @param info      the meta-data
     * @return the hash
     */
    public static Integer calculateHash(final String className, final ReflectionInfo info) {
        if (className == null) {
            throw new IllegalArgumentException("class name can not be null");
        }
        if (info == null) {
            throw new IllegalArgumentException("info can not be null");
        }
        int hash = 17;
        hash = (37 * hash) + className.hashCode();
        hash = (37 * hash) + info.hashCode();
        Integer hashKey = new Integer(hash);
        return hashKey;
    }

    /**
     * Removes the AspectWerkz specific elements from the stack trace. <p/>TODO: how to mess w/ the stacktrace in JDK
     * 1.3.x?
     *
     * @param exception the Throwable to modify the stack trace on
     * @param className the name of the fake origin class of the exception
     */
    public static void fakeStackTrace(final Throwable exception, final String className) {
        if (exception == null) {
            throw new IllegalArgumentException("exception can not be null");
        }
        if (className == null) {
            throw new IllegalArgumentException("class name can not be null");
        }

        //        final List newStackTraceList = new ArrayList();
        //        final StackTraceElement[] stackTrace = exception.getStackTrace();
        //        int i;
        //        for (i = 1; i < stackTrace.length; i++) {
        //            if (stackTrace[i].getClassName().equals(className)) break;
        //        }
        //        for (int j = i; j < stackTrace.length; j++) {
        //            newStackTraceList.add(stackTrace[j]);
        //        }
        //
        //        final StackTraceElement[] newStackTrace =
        //                new StackTraceElement[newStackTraceList.size()];
        //        int k = 0;
        //        for (Iterator it = newStackTraceList.iterator(); it.hasNext(); k++) {
        //            final StackTraceElement element = (StackTraceElement)it.next();
        //            newStackTrace[k] = element;
        //        }
        //        exception.setStackTrace(newStackTrace);
    }

    /**
     * Returns a String representation of a classloader Avoid to do a toString() if the resulting string is too long
     * (occurs on Tomcat)
     *
     * @param loader
     * @return String representation (toString or FQN@hashcode)
     */
    public static String classLoaderToString(ClassLoader loader) {
        if ((loader != null) && (loader.toString().length() < 120)) {
            return loader.toString() + "@" + loader.hashCode();
        } else if (loader != null) {
            return loader.getClass().getName() + "@" + loader.hashCode();
        } else {
            return "null";
        }
    }

    /**
     * Helper method to support Java 1.4 like Boolean.valueOf(boolean) in Java 1.3

     * @param b
     * @return
     */
    public static Boolean booleanValueOf(boolean b) {
        return b?Boolean.TRUE:Boolean.FALSE;
    }
}