net.gdface.utils.BaseParameterNames Maven / Gradle / Ivy
package net.gdface.utils;
import java.lang.reflect.Constructor;
import java.lang.reflect.Member;
import java.lang.reflect.Method;
/**
* 获取构造函数或方法的参数名基类
* 当不能获取参数名的情况下,
* {@link #returnFakeNameIfFail}为{@code false}时返回{@code null},否则返回返回arg,arg2...格式的替代名
* {@link #returnFakeNameIfFail}默认为{@code true}
* @author guyadong
*
*/
public abstract class BaseParameterNames {
protected final Class clazz;
/** 当获取无法参数名时是否返回arg,arg2...格式的替代名字 */
private boolean returnFakeNameIfFail = true;
public BaseParameterNames setReturnFakeNameIfFail(boolean returnFakeNameIfFail) {
this.returnFakeNameIfFail = returnFakeNameIfFail;
return this;
}
/**
* @param clazz 要构造函数或方法的参数名的类,为{@code null}时所有getParameterNames方法返回{@code null}
*/
public BaseParameterNames(Class clazz) {
this.clazz = clazz;
}
/**
* 获取构造函数或方法的参数名
* @param member 构造函数或方法对象
* @return 参数名列表,找不到返回{@code null}
*/
protected abstract String[] doGetParameterNames(Member member) ;
/**
* 获取构造函数或方法的参数名
* @param member 构造函数或方法对象
* @return 参数名列表,找不到时如果{@link #returnFakeNameIfFail}为{@code true}则返回arg,arg2...格式的替代名字,否则返回{@code null}
*/
public String[] getParameterNames(Member member){
String [] parameterNames = doGetParameterNames(member);
int paramCount ;
if (member instanceof Method){
paramCount = ((Method) member).getParameterTypes().length;
} else if (member instanceof Constructor){
paramCount = ((Constructor) member).getParameterTypes().length;
} else {
throw new IllegalArgumentException("member type must be Method or Constructor");
}
if(returnFakeNameIfFail && null == parameterNames){
parameterNames = new String[paramCount];
for (int i = 0; i < parameterNames.length; i++){
parameterNames[i] = String.format("arg%d", i);
}
}
return parameterNames;
}
/**
* 获取构造函数或方法的参数名
* {@code name}为{@code null}时,获取构造函数的参数名
* @param name 方法名
* @param parameterTypes 构造函数或方法的参数类型
* @return 参数名列表,找不到返回{@code null}
* @throws NoSuchMethodException
*/
public final String[] getParameterNames(String name, Class[] parameterTypes) throws NoSuchMethodException {
if(null == clazz){
return null;
}
try {
Member member = null == name ? clazz.getConstructor(parameterTypes) : clazz.getMethod(name, parameterTypes);
return getParameterNames(member);
} catch (SecurityException e) {
throw new IllegalArgumentException(e);
}
}
/**
* {@link #getParameterNames(String, Class[])}不显式抛出异常版本
* @param name
* @param parameterTypes
* @return 参数名列表,找不到将{@link NoSuchMethodException}封装到{@link RuntimeException}抛出
*/
public final String[] getParameterNamesUnchecked(String name, Class[] parameterTypes) {
try {
return getParameterNames(name, parameterTypes);
} catch (NoSuchMethodException e) {
throw new RuntimeException(e);
}
}
}