Mega Code Archive
Create new instance and invoke methods
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/**
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
**/
//package com.utils;
import java.lang.reflect.*;
//import org.apache.log4j.*;
/**
* Utilities to work with reflection.
*
* @author Erich Roncarolo
* @version 0.1 - 2004-09-07
*/
public class ClassUtil {
private ClassUtil() {
}//ClassUtil()
/**
* Returns a new instance of an object using constructor
* without arguments.
*
* @param name class name
* @return a new object instance or null if some error occours (exceptions are logged)
*/
public static Object newInstance(String name) {
return newInstance(name, null, null, false);
}//newInstance()
/**
* Returns a new instance of an object using constructor
* with arguments' running classes as parameter types.
*
* @param name class name
* @param args constructor initialization arguments
*
* @return a new object instance or null if some error occours (exceptions are logged)
*/
public static Object newInstance(String name, Object args[]) {
return newInstance(name, null, args, false);
}//newInstance()
/**
* Returns a new instance of an object using constructor with
* specified parameter types and arguments.
*
* @param name class name
* @param param constructor parameter types
* @param args constructor initialization arguments
*
* @return a new object instance or null if some error occours (exceptions are logged)
*/
public static Object newInstance(String name, Class param[], Object args[]) {
return newInstance(name, param, args, false);
}//newInstance()
/**
* Returns a new instance of an object using constructor with
* specified parameter types and arguments.
*
* @param name class name
* @param param constructor parameter types
* @param args constructor initialization arguments
* @param logException constructor initialization arguments
*
* @return a new object instance or null if some error occours (exceptions are logged)
*/
public static Object newInstance(String name, Class param[], Object args[], boolean logException) {
if (param == null && args != null) {
param = new Class[args.length];
for (int i = 0; i < param.length; i++) {
if (args[i] != null) {
param[i] = args[i].getClass();
} else {
param[i] = null;
}
}//for
}//if
Constructor c = null;
Object obj = null;
try {
c = Class.forName(name).getConstructor(param);
if (c != null) {
obj = c.newInstance(args);
}
} catch (Exception x) {
if (logException) {
// Logger log = Logger.getLogger(ClassUtil.class);
// log.error("", x);
}
return null;
}
return obj;
}//newInstance()
/**
* Returns a new instance of an object using constructor
* without arguments.
*
* @param clazz object class
* @return a new object instance or null if some error occours (exceptions are logged)
*/
public static Object newInstance(Class clazz) {
return newInstance(clazz, null, null);
}//newInstance()
/**
* Returns a new instance of an object using constructor
* with arguments' running classes as parameter types.
*
* @param clazz object class
* @param args constructor initialization arguments
*
* @return a new object instance or null if some error occours (exceptions are logged)
*/
public static Object newInstance(Class clazz, Object args[]) {
return newInstance(clazz, null, args);
}//newInstance()
/**
* Returns a new instance of an object using constructor with
* specified parameter types and arguments.
*
* @param clazz object class
* @param param constructor parameter types
* @param args constructor initialization arguments
*
* @return a new object instance or null if some error occours (exceptions are logged)
*/
public static Object newInstance(Class clazz, Class param[], Object args[]) {
if (clazz == null) {
return null;
}
String name = clazz.getName();
return newInstance(name, param, args);
}//newInstance()
/**
* Invokes the object's method with specified parameter types and arguments.
*
* @param obj the object the specified method is invoked from (use a Class object if method is static)
* @param name method name
* @param param constructor parameter types
* @param args constructor initialization arguments
*
* @return a new object instance or null if some error occours (exceptions are logged)
*/
public static Object invokeMethod(Object obj, String name, Class param[], Object args[]) {
if (param == null && args != null) {
param = new Class[args.length];
for (int i = 0; i < param.length; i++) {
if (args[i] != null) {
param[i] = args[i].getClass();
} else {
param[i] = null;
}
}//for
}//if
Method m = null;
Object ret = null;
try {
if (obj instanceof Class) {
m = ((Class) obj).getMethod(name, param);
} else {
m = obj.getClass().getMethod(name, param);
}
if (m != null) {
ret = m.invoke(obj, args);
}
} catch (NoSuchMethodException x) {
// Logger log = Logger.getLogger(ClassUtil.class);
//log.warn("No method "+(obj instanceof Class ? (Class)obj : obj.getClass()).toString()+"."+name+"("+Arrays.asList(param)+") found - "+TnesException.firstStackTrace(x));
return null;
} catch (Exception x) {
//Logger log = Logger.getLogger(ClassUtil.class);
// log.error("", x);
return null;
}
return ret;
}//invokeMethod()
/**
* Invokes the object's method with specified arguments.
*
* @param obj the object the specified method is invoked from (use a Class object if method is static)
* @param name method name
* @param args constructor initialization arguments
*
* @return a new object instance or null if some error occours (exceptions are logged)
*/
public static Object invokeMethod(Object obj, String name, Object args[]) {
return invokeMethod(obj, name, null, args);
}//invokeMethod()
/**
* Invokes the object's method with no arguments.
*
* @param obj the object the specified method is invoked from (use a Class object if method is static)
* @param name method name
*
* @return a new object instance or null if some error occours (exceptions are logged)
*/
public static Object invokeMethod(Object obj, String name) {
return invokeMethod(obj, name, null, null);
}//invokeMethod()
}//ClassUtil
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