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Posted to dev@commons.apache.org by sc...@apache.org on 2002/09/07 00:42:39 UTC
cvs commit: jakarta-commons-sandbox/lang ClassUtils.java
scolebourne 2002/09/06 15:42:39
Added: lang ClassUtils.java
Log:
Store in lang sandbox for the moment
Revision Changes Path
1.1 jakarta-commons-sandbox/lang/ClassUtils.java
Index: ClassUtils.java
===================================================================
/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2002 The Apache Software Foundation. All rights
* reserved.
*
* 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.
*
* 3. The end-user documentation included with the redistribution, if
* any, must include the following acknowlegement:
* "This product includes software developed by the
* Apache Software Foundation (http://www.apache.org/)."
* Alternately, this acknowlegement may appear in the software itself,
* if and wherever such third-party acknowlegements normally appear.
*
* 4. The names "The Jakarta Project", "Commons", and "Apache Software
* Foundation" must not be used to endorse or promote products derived
* from this software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* nor may "Apache" appear in their names without prior written
* permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
* ITS 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
/**
* A set of static utilities for use with ClassUtils.
*
* @author bayard@generationjava.com
* @version $Id: ClassUtils.java,v 1.1 2002/09/06 22:42:38 scolebourne Exp $
*/
final public class ClassUtils {
/**
* Create an object from the classname. Must have an empty constructor.
*
* @param classname String name of the class
*
* @return Object instance of the class or null
*/
static public Object createObject(String classname) {
Class tmpClass = null;
tmpClass = getClass(classname);
return createObject(tmpClass);
}
/**
* Create an object from a class.
*
* @param clss Class object to instantiate
*
* @return Object instance of the class or null
*/
static public Object createObject(Class clss) {
try {
return clss.newInstance();
} catch (IllegalAccessException iae) {
System.err.println("Cant instantiate " + clss.getName() + " because " +
iae.getMessage());
} catch (InstantiationException ie) {
System.err.println("Cant instantiate " + clss.getName() + " because " +
ie.getMessage());
}
return null;
}
/**
* Is this Class in the CLASSPATH
*
* @param classname String of the class
*
* @return boolean exists or not.
*/
static public boolean classExists(String classname) {
Class tmpClass = null;
/* try and load class */
try {
tmpClass = Class.forName(classname);
} catch (ClassNotFoundException cnfe) {
return false;
} catch (IllegalArgumentException iae) {
return false;
}
return true;
}
/**
* Get the Class object for a classname.
*
* @param classname String of the class
*
* @return Class instance for the class.
*/
static public Class getClass(String classname) {
Class tmpClass = null;
/* try an load class */
try {
tmpClass = Class.forName(classname);
} catch (ClassNotFoundException cnfe) {
System.out.println("Can't resolve classname " + classname);
} catch (IllegalArgumentException iae) {
System.err.println("Cant resolve " + tmpClass.getName() + " because " + iae.getMessage());
}
return tmpClass;
}
/**
* Is this Class object an instance of the class with this name.
*
* @param clss Class instance
* @param inst String name of potential supertype
*
* @return boolean was it an instanceof
*/
static public boolean classInstanceOf(Class clss, String inst) {
if(classImplements(clss,inst)) {
return true;
} else
if(classExtends(clss,inst)) {
return true;
} else {
return false;
}
}
/**
* Does this Class implement an interface with this name.
*
* @param clss Class instance
* @param exts String name of potential interface
*
* @return boolean was it an implementor
*/
static public boolean classImplements(Class clss, String exts) {
Class sprcls = clss;
Class excls = getClass(exts);
while(sprcls != null) {
Class[] interfaces = sprcls.getInterfaces();
for(int i=0;i<interfaces.length;i++) {
if(interfaces[i].equals(excls)) {
return true;
}
}
sprcls = sprcls.getSuperclass();
}
return false;
}
/**
* Does this Class extend a superclass with this name.
*
* @param clss Class instance
* @param exts String name of potential superclass
*
* @return boolean was it a superclass
*/
static public boolean classExtends(Class clss, String exts) {
if(clss == null) {
return false;
}
if(clss.getName().equals(exts)) {
return true;
}
Class sprcls = clss.getSuperclass();
Class excls = getClass(exts);
// while(! sprcls.equals(sprcls.getSuperclass()) ) {
while( sprcls != null ) {
if(sprcls.equals(excls)) {
return true;
}
sprcls = sprcls.getSuperclass();
}
return false;
}
}
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