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A Java library of bean utilities for manipulating and inspecting Java classes implementing the Java Beans standard
There is a newer version: 1.0.3

package org.exparity.beans;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.lang.StringUtils;

/**
 * Utility methods for accessing {@link java.lang.reflect.Method} properties
 * 
 * @author Stewart Bissett
 */
public class MethodUtils {

	private static final String SET_PREFIX = "set";
	private static final String GET_PREFIX = "get";
	private static final String IS_PREFIX = "is";

	public static boolean isAccessor(final Method method) {
		if (method.getParameterTypes().length == 0) {
			return method.getName().startsWith(GET_PREFIX) || method.getName().startsWith(IS_PREFIX);
		} else {
			return false;
		}
	}

	public static boolean isSetter(final Method method) {
		return method.getName().startsWith(SET_PREFIX) && method.getParameterTypes().length == 1;
	}

	public static String toPropertyName(final Method method, final BeanNamingStrategy naming) {
		if (isSetter(method)) {
			return naming.describeProperty(method, SET_PREFIX);
		} else if (isAccessor(method)) {
			if (method.getName().startsWith(IS_PREFIX)) {
				return naming.describeProperty(method, IS_PREFIX);
			} else if (method.getName().startsWith(GET_PREFIX)) {
				return naming.describeProperty(method, GET_PREFIX);
			} else {
				throw new RuntimeException("Getter which is not prefixed with is or get");
			}
		} else {
			throw new IllegalArgumentException("Method does match the standards for bean properties");
		}

	}

	public static Class[] genericArgs(final Method accessor) {
		Type type = accessor.getGenericReturnType();
		if (type instanceof ParameterizedType) {
			List> params = new ArrayList>();
			for (Type arg : ((ParameterizedType) type).getActualTypeArguments()) {
				if (arg instanceof Class) {
					params.add((Class) arg);
				}
			}
			return params.toArray(new Class[0]);
		} else {
			return new Class[0];
		}
	}

	public static Object invoke(final Method accessor, final Object instance) {
		try {
			return accessor.invoke(instance);
		} catch (IllegalArgumentException e) {
			throw new BeanPropertyException("Method '" + accessor.getName() + "' does not exist on '" + instance.getClass() + "'");
		} catch (IllegalAccessException e) {
			throw new BeanPropertyException("Illegal Access exception encountered whilst calling '" + accessor.getName() + " on '" + instance.getClass().getCanonicalName() + "'",
					e);
		} catch (InvocationTargetException e) {
			throw new BeanPropertyException("Unexpected exception whilst calling '" + accessor.getName() + " on '" + instance.getClass().getCanonicalName() + "'", e.getCause());
		}
	}

	public static boolean invoke(final Method mutator, final Object instance, final Object value) {
		try {
			mutator.invoke(instance, value);
		} catch (IllegalArgumentException e) {
			throw new BeanPropertyException("Method '" + mutator.getName()
					+ " on '"
					+ instance.getClass().getCanonicalName()
					+ "' expected arguments '"
					+ StringUtils.join(mutator.getParameterTypes())
					+ "'  but was supplied a '"
					+ value.getClass().getSimpleName(), e);
		} catch (IllegalAccessException e) {
			throw new BeanPropertyException("Illegal Access exception encountered whilst calling '" + mutator.getName() + " on '" + instance.getClass().getCanonicalName() + "'", e);
		} catch (InvocationTargetException e) {
			throw new BeanPropertyException("Unexpected exception whilst calling '" + mutator.getName() + " on '" + instance.getClass().getCanonicalName() + "'",
					e.getTargetException());
		}
		return true;
	}

	public static Method getMethod(final Class type, final String methodName) {
		try {
			return type.getMethod(methodName);
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

}