org.codehaus.gmavenplus.util.ReflectionUtils Maven / Gradle / Ivy
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Integrates Groovy into Maven projects.
/*
* Copyright (C) 2011 the original author or authors.
*
* 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 org.codehaus.gmavenplus.util;
import java.lang.reflect.*;
import java.util.Arrays;
/**
* Inspired by Spring's ReflectionUtils.
*
* @author Keegan Witt
* @since 1.0-beta-1
*/
public class ReflectionUtils {
/**
* Private constructor that should never be called since this is a static utility class.
*/
private ReflectionUtils() { }
/**
* Attempt to find a {@link Method} on the supplied class with the supplied name
* and parameter types. Searches all superclasses up to Object.
*
* @param clazz The class to introspect
* @param name The name of the method
* @param paramTypes The parameter types of the method
* (may be null to indicate any signature)
* @return The Method object
*/
public static Method findMethod(final Class clazz, final String name, final Class... paramTypes) {
if (clazz == null) {
throw new IllegalArgumentException("Class must not be null.");
}
if (name == null) {
throw new IllegalArgumentException("Method name must not be null.");
}
Class searchType = clazz;
while (searchType != null) {
Method[] methods = searchType.isInterface() ? searchType.getMethods() : searchType.getDeclaredMethods();
for (Method method : methods) {
if (name.equals(method.getName()) && (paramTypes == null || Arrays.equals(paramTypes, method.getParameterTypes()))) {
return method;
}
}
searchType = searchType.getSuperclass();
}
throw new IllegalArgumentException("Unable to find method " + clazz.getName() + "." + name + "(" + Arrays.toString(paramTypes).replaceAll("^\\[", "").replaceAll("\\]$", "").replaceAll("class ", "") + ").");
}
/**
* Attempt to find a {@link Constructor} on the supplied class with the supplied
* parameter types. Searches all superclasses up to Object.
*
* @param clazz The class to introspect
* @param paramTypes The parameter types of the method
* (may be null to indicate any signature)
* @return The Constructor object
*/
public static Constructor findConstructor(final Class clazz, final Class... paramTypes) {
if (clazz == null) {
throw new IllegalArgumentException("Class must not be null.");
}
Class searchType = clazz;
while (searchType != null) {
Constructor[] constructors = searchType.isInterface() ? searchType.getConstructors() : searchType.getDeclaredConstructors();
for (Constructor constructor : constructors) {
if (paramTypes == null || Arrays.equals(paramTypes, constructor.getParameterTypes())) {
return constructor;
}
}
searchType = searchType.getSuperclass();
}
throw new IllegalArgumentException("Unable to find constructor " + clazz.getName() + "(" + Arrays.toString(paramTypes).replaceAll("^\\[", "").replaceAll("\\]$", "").replaceAll("class ", "") + ").");
}
/**
* Invoke the specified {@link Method} against the supplied target object with the
* supplied arguments. The target object can be null when invoking a
* static {@link Method}.
*
* @param method The method to invoke
* @param target The target object to invoke the method on
* @param args The invocation arguments (may be null)
* @return The invocation result, if any
* @throws IllegalAccessException When unable to access the specified method because access modifiers prevent it
* @throws java.lang.reflect.InvocationTargetException When a reflection invocation fails
*/
public static Object invokeMethod(final Method method, final Object target, final Object... args) throws InvocationTargetException, IllegalAccessException {
if (method == null) {
throw new IllegalArgumentException("Method must not be null.");
}
if (target == null) {
throw new IllegalArgumentException("Object must not be null.");
}
method.setAccessible(true);
return method.invoke(target, args);
}
/**
* Invoke the specified static {@link Method} with the supplied arguments.
*
* @param method The method to invoke
* @param args The invocation arguments (may be null)
* @return The invocation result, if any
* @throws IllegalAccessException When unable to access the specified method because access modifiers prevent it
* @throws java.lang.reflect.InvocationTargetException When a reflection invocation fails
*/
public static Object invokeStaticMethod(final Method method, final Object... args) throws InvocationTargetException, IllegalAccessException {
if (method == null) {
throw new IllegalArgumentException("Method must not be null.");
}
if (!Modifier.isStatic(method.getModifiers())) {
throw new IllegalArgumentException("Method must be static.");
}
method.setAccessible(true);
return method.invoke(null, args);
}
/**
* Invoke the specified {@link Constructor} with the supplied arguments.
*
* @param constructor The method to invoke
* @param args The invocation arguments (may be null)
* @return The invocation result, if any
* @throws IllegalAccessException When unable to access the specified constructor because access modifiers prevent it
* @throws java.lang.reflect.InvocationTargetException When a reflection invocation fails
* @throws InstantiationException When an instantiation fails
*/
public static Object invokeConstructor(final Constructor constructor, final Object... args) throws InvocationTargetException, IllegalAccessException, InstantiationException {
if (constructor == null) {
throw new IllegalArgumentException("Constructor must not be null.");
}
constructor.setAccessible(true);
return constructor.newInstance(args);
}
/**
* Attempt to find a {@link Field field} on the supplied {@link Class} with the
* supplied name and/or {@link Class type}. Searches all superclasses
* up to {@link Object}.
*
* @param clazz The class to introspect
* @param name The name of the field (may be null if type is specified)
* @param type The type of the field (may be null if name is specified)
* @return The corresponding Field object
*/
public static Field findField(final Class clazz, final String name, final Class type) {
if (clazz == null) {
throw new IllegalArgumentException("Class must not be null");
}
if (name == null && type == null) {
throw new IllegalArgumentException("Either name or type of the field must be specified.");
}
Class searchType = clazz;
while (!Object.class.equals(searchType) && searchType != null) {
Field[] fields = searchType.getDeclaredFields();
for (Field field : fields) {
if ((name == null || name.equals(field.getName())) && (type == null || type.equals(field.getType()))) {
return field;
}
}
searchType = searchType.getSuperclass();
}
throw new IllegalArgumentException("Unable to find " + (type != null ? type.getName() : "") + " " + (name != null ? name : "") + ".");
}
/**
* Get the field represented by the supplied {@link Field field object} on the
* specified {@link Object target object}. In accordance with {@link Field#get(Object)}
* semantics, the returned value is automatically wrapped if the underlying field
* has a primitive type.
* @param field The field to get
* @param target The target object from which to get the field
* @return The field's current value
* @throws IllegalAccessException When unable to access the specified field because access modifiers prevent it
*/
public static Object getField(final Field field, final Object target) throws IllegalAccessException {
field.setAccessible(true);
return field.get(target);
}
/**
* Get the field represented by the supplied {@link Field field object} on the
* specified {@link Object target object}. In accordance with {@link Field#get(Object)}
* semantics, the returned value is automatically wrapped if the underlying field
* has a primitive type.
*
* @param field The field to get
* @return The field's current value
* @throws IllegalAccessException When unable to access the specified field because access modifiers prevent it
*/
public static Object getStaticField(final Field field) throws IllegalAccessException {
if (!Modifier.isStatic(field.getModifiers())) {
throw new IllegalArgumentException("Field must be static.");
}
return getField(field, null);
}
/**
* Find and return the specified value from the specified enum class.
*
* @param clazz The enum class to introspect
* @param valueName The name of the enum value to get
*
* @return The enum value
*/
public static Object getEnumValue(final Class clazz, final String valueName) {
if (clazz.isEnum()) {
for (Object o : clazz.getEnumConstants()) {
if (o.toString().equals(valueName)) {
return o;
}
}
throw new IllegalArgumentException("Unable to get an enum constant with that name.");
} else {
throw new IllegalArgumentException(clazz + " must be an enum.");
}
}
}
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