ClassUtils.java

/*
 * 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.asual.summer.core.util;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;

import javax.inject.Named;

import org.springframework.util.ReflectionUtils;

/**
 * 
 * @author Rostislav Hristov
 *
 */
@Named
public class ClassUtils {
	
	public static Class<?> getClass(String clazz) throws ClassNotFoundException {
		return Class.forName(clazz);
	}
	
	public static Object cast(Object obj, String clazz) throws ClassNotFoundException {
		return Class.forName(clazz).cast(obj);
	}
	
	public static boolean isInstance(Object obj, String clazz) {
		try {
			return Class.forName(clazz).isInstance(obj);
		} catch (ClassNotFoundException e) {
			return false;
		}
	}

	public static Object newInstance(String clazz, Object... parameters) throws SecurityException, ClassNotFoundException {
		Class<?>[] classParameters = new Class[parameters == null ? 0 : parameters.length];
		for (int i = 0; i < classParameters.length; i++) {
			classParameters[i] = parameters[i].getClass();
		}
		Object instance = null;
		try {
			instance = Class.forName(clazz).getConstructor(classParameters).newInstance(parameters == null ? new Object[] {} : parameters.length);
		} catch (Exception e) {
			Constructor<?>[] constructors = Class.forName(clazz).getConstructors();
			for (Constructor<?> constructor : constructors) {
				Class<?>[] types = constructor.getParameterTypes();
				if (types.length == parameters.length) {
					Object[] params = new Object[parameters.length];
					for (int i = 0; i < parameters.length; i++) {
						if (types[i] == boolean.class || types[i] == Boolean.class) {
							params[i] = Boolean.valueOf(parameters[i].toString());
						} else if (types[i] == int.class || types[i] == Integer.class) {
							params[i] = Integer.valueOf(parameters[i].toString());
						} else {
							params[i] = types[i].cast(parameters[i]);
						}
					}
					try {
						instance = constructor.newInstance(params);
						break;
					} catch (Exception ex) {
						continue;
					}
				}
			}
		}
		return instance;
	}

	public static Object invokeMethod(Object target, final String methodName, final Object[] parameters) {
		if (target != null) {
			final List<Method> matches = new ArrayList<Method>();
			ReflectionUtils.doWithMethods(target.getClass(), new ReflectionUtils.MethodCallback() {
				public void doWith(Method method) throws IllegalArgumentException,
						IllegalAccessException {
					matches.add(method);
				}
			}, 
			new ReflectionUtils.MethodFilter() {
				public boolean matches(Method method) {
					if (method.getName().equals(methodName)) {
						Class<?>[] types = method.getParameterTypes();
						if (parameters == null && types.length == 0) {
							return true;
						}
						if (types.length != parameters.length) {
							return false;
						}
						for (int i = 0; i < types.length; i++) {
							if (!types[i].isInstance(parameters[i])) {
								return false;
							}
						}
						return true;
					}
					return false;
				}
			});
			if (matches.size() > 0) {
				if (parameters == null) {
					return ReflectionUtils.invokeMethod(matches.get(0), target);
				} else {
					return ReflectionUtils.invokeMethod(matches.get(0), target, parameters);				
				}
			}
		}
		return null;
	}
	
}