cn.easyes.extension.plugins.Plugin Maven / Gradle / Ivy

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package cn.easyes.extension.plugins;


import cn.easyes.annotation.Intercepts;
import cn.easyes.annotation.Signature;
import cn.easyes.common.utils.ExceptionUtils;
import cn.easyes.extension.context.Interceptor;
import cn.easyes.extension.context.Invocation;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

/**
 * 
 * 插件代理
 * 
 *
 * @author lilu
 * @since 2022/3/4
 */
public class Plugin implements InvocationHandler {

    private final Object target;
    private final Interceptor interceptor;
    private final Map, Set> signatureMap;

    private Plugin(Object target, Interceptor interceptor, Map, Set> signatureMap) {
        this.target = target;
        this.interceptor = interceptor;
        this.signatureMap = signatureMap;
    }

    /**
     * 包装代理
     *
     * @param t           泛型
     * @param interceptor 拦截器
     * @param          泛型
     * @return 泛型
     */
    @SuppressWarnings("unchecked")
    public static  T wrap(T t, Interceptor interceptor) {
        Map, Set> signatureMap = getSignatureMap(interceptor);
        return (T) Proxy.newProxyInstance(
                t.getClass().getClassLoader(),
                t.getClass().getInterfaces(),
                new Plugin(t, interceptor, signatureMap));
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        try {
            Set methods = signatureMap.get(method.getDeclaringClass());
            if (methods != null && methods.contains(method)) {
                return interceptor.intercept(new Invocation(target, method, args));
            }
            return method.invoke(target, args);
        } catch (Exception e) {
            throw ExceptionUtils.unwrapThrowable(e);
        }
    }

    private static Map, Set> getSignatureMap(Interceptor interceptor) {
        Intercepts interceptsAnnotation = interceptor.getClass().getAnnotation(Intercepts.class);
        // 检查类是否被@Intercepts标记
        if (interceptsAnnotation == null) {
            throw new RuntimeException("No @Intercepts annotation was found in interceptor " + interceptor.getClass().getName());
        }
        Signature[] sigs = interceptsAnnotation.value();
        Map, Set> signatureMap = new HashMap<>();
        // 检查被@Signature标记的方法是否存在
        for (Signature sig : sigs) {
            Set methods = signatureMap.computeIfAbsent(sig.type(), k -> new HashSet<>());
            try {
                Method method = sig.type().getMethod(sig.method(), sig.args());
                methods.add(method);
            } catch (NoSuchMethodException e) {
                throw new RuntimeException("Could not find method on " + sig.type() + " named " + sig.method() + ". Cause: " + e, e);
            }
        }
        return signatureMap;
    }

}