nosum-spring/src/main/java/cn/nosum/framework/aop/support/AdvisedSupport.java

package cn.nosum.framework.aop.support;


import cn.nosum.framework.aop.aspect.Advice;
import cn.nosum.framework.aop.config.AopConfig;
import cn.nosum.util.StringUtils;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Pattern;
import java.util.regex.Matcher;

public class AdvisedSupport {

    // 保存读取到的配置
    private AopConfig config;
    private Object target;
    private Class targetClass;
    private Pattern pointCutClassPattern;

    private Map<Method,Map<String,Advice>> methodCache;

    public AdvisedSupport(AopConfig config) {
        this.config = config;
    }

    // 解析配置文件的方法
    private void parse() {
        // 把 Spring 的 Expression 变成Java能够识别的正则表达式
        String pointCut = config.getPointCut()
                .replaceAll("\\.", "\\\\.")
                .replaceAll("\\\\.\\*", ".*")
                .replaceAll("\\(", "\\\\(")
                .replaceAll("\\)", "\\\\)");


        // 保存专门匹配 Class 的正则
        String pointCutForClassRegex = pointCut.substring(0, pointCut.lastIndexOf("\\(") - 4);
        pointCutClassPattern = Pattern.compile("class " + pointCutForClassRegex.substring(pointCutForClassRegex.lastIndexOf(" ") + 1));
        if (pointCutMath()){
            // 缓存
            this.methodCache = new HashMap<Method, Map<String, Advice>>();
            // 保存专门匹配方法的正则
            Pattern pointCutPattern = Pattern.compile(pointCut);
            try{
                // 切面类，用户自己定义
                Class aspectClass = Class.forName(this.config.getAspectClass());
                Map<String,Method> aspectMethods = new HashMap<String, Method>();
                // 取得切面类中的所有方法
                for (Method method : aspectClass.getMethods()) {
                    aspectMethods.put(method.getName(),method);
                }
                // 取得目标代理对象的所有方法
                for (Method method : this.targetClass.getMethods()) {
                    String methodString = method.toString();
                    // 截取方法名称
                    if(methodString.contains("throws")){
                        methodString = methodString.substring(0,methodString.lastIndexOf("throws")).trim();
                    }
                    // 判断是否在切面的范围
                    Matcher matcher = pointCutPattern.matcher(methodString);
                    if(matcher.matches()){
                        Map<String,Advice> advices = new HashMap<String, Advice>();
                        // 增加方法执行前的切面
                        if(StringUtils.isNotEmpty(config.getAspectBefore())){
                            advices.put("before",new Advice(aspectClass.newInstance(),aspectMethods.get(config.getAspectBefore())));
                        }
                        // 增加方法执行后的切面
                        if(StringUtils.isNotEmpty(config.getAspectAfter())){
                            advices.put("after",new Advice(aspectClass.newInstance(),aspectMethods.get(config.getAspectAfter())));
                        }
                        // 增加方法执行异常的切面
                        if(StringUtils.isNotEmpty(config.getAspectAfterThrow())){
                            Advice advice = new Advice(aspectClass.newInstance(),aspectMethods.get(config.getAspectAfterThrow()));
                            // 设置要捕获的异常
                            advice.setThrowName(config.getAspectAfterThrowingName());
                            advices.put("afterThrow",advice);
                        }
                        // 跟目标代理类的业务方法和 Advices 建立一对多关联关系，以便在 Proxy 类中获得
                        this.methodCache.put(method,advices);
                    }
                }
            }catch(Exception e){
                e.printStackTrace();
            }
        }
    }



    // 根据一个目标代理类的方法，获得其对应的通知
    public Map<String,Advice> getAdvices(Method method) throws NoSuchMethodException {
        //享元设计模式的应用
        Map<String,Advice> cache = methodCache.get(method);
        if(null == cache){
            // 如果是通过父类的接口调用，无法根据key进行获取，此时，取得子类方法，并且调用
            Method m = targetClass.getMethod(method.getName(),method.getParameterTypes());
            cache = methodCache.get(m);
            // 缓存
            this.methodCache.put(method,cache);
        }
        return cache;
    }

    // IOC 中的对象初始化时调用，决定要不要生成代理类的逻辑
    public boolean pointCutMath() {
        return pointCutClassPattern.matcher(this.targetClass.toString()).matches();
    }

    public void setTargetClass(Class<?> targetClass) {
        this.targetClass = targetClass;
        parse();
    }

    public void setTarget(Object target) {
        this.target = target;
    }

    public Class getTargetClass() {
        return targetClass;
    }

    public Object getTarget() {
        return target;
    }
}