package test.logging.interceptor;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.apache.log4j.Logger;

public class LoggingInterceptor implements MethodInterceptor {
    private Logger logger;

    public Object invoke(MethodInvocation invocation) throws Throwable {
        // クラス名とメソッド名を取得
        String className = null;
        String methodName = null;

        // debugによるロギングが有効の場合のみ
        if (this.logger.isDebugEnabled()) {
            className = invocation.getThis().getClass().getName();
            methodName = invocation.getMethod().getName();

            StringBuffer paramBuf = new StringBuffer();
            paramBuf.append(className).append("#").append(methodName).append(" params");

            // 呼び出しパラメータと型
            Object[] args = invocation.getArguments();
            Class<?>[] paramClasses = invocation.getMethod().getParameterTypes();

            if (args == null || args.length == 0) {
                paramBuf.append("(<パラメータ無し>)");
            } else {
                paramBuf.append("(");
                boolean isFirst = true;
                for (int i = 0; i < args.length; i++) {
                    if (!isFirst) {
                        paramBuf.append(", ");
                    }
                    Object o = args[i];
                    if (o == null) {
                        paramBuf.append("null");
                    } else {
                        paramBuf.append(paramClasses[i].getSimpleName()).append("[").append(o.toString()).append("]");
                    }
                    isFirst = false;
                }
                paramBuf.append(")");
            }
            this.logger.debug(paramBuf.toString());
        }

        // 対象処理を実行
        Object result = invocation.proceed();

        // debugによるロギングが有効の場合のみ
        if (this.logger.isDebugEnabled()) {
            StringBuffer returnBuf = new StringBuffer();
            returnBuf.append(className).append("#").append(methodName).append(" return");

            // 戻り値と型
            Class<?> returnClass = invocation.getMethod().getReturnType();

            if (returnClass == Void.TYPE) {
                returnBuf.append("(<戻り値無し>)");
            } else {
                returnBuf.append("(");
                if (result == null) {
                    returnBuf.append("null");
                } else {
                    returnBuf.append(returnClass.getSimpleName()).append("[").append(result.toString()).append("]");
                }
                returnBuf.append(")");
            }
            this.logger.debug(returnBuf.toString());
        }

        return result;
    }

    public Logger getLogger() {
        return this.logger;
    }

    public void setLogger(Logger logger) {
        this.logger = logger;
    }
}