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/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 2014-2015 Oracle and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
* or packager/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at packager/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
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* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
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*/
package org.glassfish.hk2.utilities.general;
import java.lang.reflect.Array;
import org.glassfish.hk2.utilities.general.internal.WeakHashClockImpl;
import org.glassfish.hk2.utilities.general.internal.WeakHashLRUImpl;
/**
* This class contains utilities useful for any code
*
* @author jwells
*
*/
public class GeneralUtilities {
/**
* Returns true if a is equals to b, or both
* and and b are null. Is safe even if
* a or b is null. If a or b is null but
* the other is not null, this returns false
*
* @param a A possibly null object to compare
* @param b A possibly null object to compare
* @return true if equal, false if not
*/
public static boolean safeEquals(Object a, Object b) {
if (a == b) return true;
if (a == null) return false;
if (b == null) return false;
return a.equals(b);
}
private static Class loadArrayClass(ClassLoader cl, String aName) {
Class componentType = null;
int[] dimensions = null;
int dot = 0;
while (componentType == null) {
char dotChar = aName.charAt(dot);
if (dotChar == '[') {
dot++;
continue;
}
dimensions = new int[dot];
for (int lcv = 0; lcv < dot; lcv++) {
dimensions[lcv] = 0;
}
if (dotChar == 'B') {
componentType = byte.class;
}
else if (dotChar == 'I') {
componentType = int.class;
}
else if (dotChar == 'J') {
componentType = long.class;
}
else if (dotChar == 'Z') {
componentType = boolean.class;
}
else if (dotChar == 'S') {
componentType = short.class;
}
else if (dotChar == 'C') {
componentType = char.class;
}
else if (dotChar == 'D') {
componentType = double.class;
}
else if (dotChar == 'F') {
componentType = float.class;
}
else {
if (dotChar != 'L') {
throw new IllegalArgumentException("Unknown array type " + aName);
}
if (aName.charAt(aName.length() - 1) != ';') {
throw new IllegalArgumentException("Badly formed L array expresion: " + aName);
}
String cName = aName.substring(dot + 1, aName.length() - 1);
componentType = loadClass(cl, cName);
if (componentType == null) return null;
}
}
Object retArray = Array.newInstance(componentType, dimensions);
return retArray.getClass();
}
/**
* Loads the class from the given classloader or returns null (does not throw).
* Property handles array classes as well
*
* @param cl The non-null classloader to load the class from
* @param cName The fully qualified non-null name of the class to load
* @return The class if it could be loaded from the classloader, or
* null if it could not be found for any reason
*/
public static Class loadClass(ClassLoader cl, String cName) {
if (cName.startsWith("[")) {
return loadArrayClass(cl, cName);
}
try {
return cl.loadClass(cName);
}
catch (Throwable th) {
return null;
}
}
/**
* Creates a weak hash clock
* @param isWeak if true this will keep weak keyes, if false the keys will
* be hard and will not go away even if they do not exist anywhere else
* but this cache
* @return A weak hash clock implementation
*/
public static WeakHashClock getWeakHashClock(boolean isWeak) {
return new WeakHashClockImpl(isWeak);
}
/**
* Creates a weak hash clock
* @param isWeak if true this will keep weak keyes, if false the keys will
* be hard and will not go away even if they do not exist anywhere else
* but this cache
* @return A weak hash clock implementation
*/
public static WeakHashLRU getWeakHashLRU(boolean isWeak) {
return new WeakHashLRUImpl(isWeak);
}
}