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// Copyright (C) 2003 Jon A. Maxwell (JAM)
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
package net.sourceforge.jnlp.util;
import java.lang.reflect.*;
/**
* Provides simply, convenient methods to invoke methods by
* name. This class is used to consolidate reflection needed to
* access methods specific to Sun's JVM or to remain backward
* compatible while supporting method in newer JVMs.<p>
*
* Most methods of this class invoke the first method on the
* specified object that matches the name and number of
* parameters. The type of the parameters are not considered, so
* do not attempt to use this class to invoke overloaded
* methods.<p>
*
* Instances of this class are not synchronized.<p>
*
* @author <a href="mailto:jon.maxwell@acm.org">Jon A. Maxwell (JAM)</a> - initial author
* @version $Revision: 1.1 $
*/
public class Reflect {
// todo: check non-null parameter types, try to send to proper
// method if overloaded ones exist on the target object
// todo: optimize slightly using hashtable of Methods
private boolean accessible;
private static Object zero[] = new Object[0];
/**
* Create a new Reflect instance.
*/
public Reflect() {
//
}
/**
* Create a new Reflect instance.
*
* @param accessible whether to bypass access permissions
*/
public Reflect(boolean accessible) {
this.accessible = accessible;
}
/**
* Invoke a zero-parameter static method by name.
*/
public Object invokeStatic(String className, String method) {
return invokeStatic(className, method, zero);
}
/**
* Invoke the static method using the specified parameters.
*/
public Object invokeStatic(String className, String method, Object args[]) {
try {
Class c = Class.forName(className, true, Reflect.class.getClassLoader());
Method m = getMethod(c, method, args);
if (m.isAccessible() != accessible)
m.setAccessible(accessible);
return m.invoke(null, args);
} catch (Exception ex) { // eat
return null;
}
}
/**
* Invoke a zero-parameter method by name on the specified
* object.
*/
public Object invoke(Object object, String method) {
return invoke(object, method, zero);
}
/**
* Invoke a method by name with the specified parameters.
*
* @return the result of the method, or null on exception.
*/
public Object invoke(Object object, String method, Object args[]) {
try {
Method m = getMethod(object.getClass(), method, args);
if (m.isAccessible() != accessible)
m.setAccessible(accessible);
return m.invoke(object, args);
} catch (Exception ex) { // eat
ex.printStackTrace();
return null;
}
}
/**
* Return the Method matching the specified name and number of
* arguments.
*/
public Method getMethod(Class type, String method, Object args[]) {
try {
for (Class c = type; c != null; c = c.getSuperclass()) {
Method methods[] = c.getMethods();
for (int i = 0; i < methods.length; i++) {
if (methods[i].getName().equals(method)) {
Class parameters[] = methods[i].getParameterTypes();
if (parameters.length == args.length)
return methods[i];
}
}
}
} catch (Exception ex) { // eat
ex.printStackTrace();
}
return null;
}
}
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