com.lithium.dbi.rdbi.MethodContextInterceptor Maven / Gradle / Ivy

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package com.lithium.dbi.rdbi;

import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.exceptions.JedisDataException;

import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

class MethodContextInterceptor implements MethodInterceptor {

    private final Jedis jedis;
    private final Map contexts;

    public MethodContextInterceptor(Jedis jedis, Map contexts) {
        this.jedis = jedis;
        this.contexts = contexts;
    }

    @Override
    @SuppressWarnings("unchecked")
    public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {

        MethodContext context = contexts.get(method);

        Object ret = context.hasDynamicLists() ? callEvalDynamicList(context, objects)
                                               : callEval(context, objects);

        if (ret == null) {
            return null;
        }

        if (contexts.get(method).getMapper() != null) {
            return contexts.get(method).getMapper().map(ret);
        } else {
            return ret;
        }
    }

    @SuppressWarnings("unchecked")
    private Object callEval(MethodContext context, Object[] objects) {

        List keys = objects.length > 0 ? (List) objects[0] : null;
        List argv = objects.length > 1 ? (List) objects[1] : null;

        return  evalShaHandleReloadScript(context, keys, argv);
    }

    private Object callEvalDynamicList(MethodContext context, Object[] objects) {

        List keys = new ArrayList<>();
        List argv = new ArrayList<>();

        for (int i = 0; i < objects.length; i++) {
            if (context.getLuaContext().isKey(i)) {
                keys.add(objects[i].toString());
            } else {
                argv.add(objects[i].toString());
            }
        }

        return  evalShaHandleReloadScript(context, keys, argv);
    }

    private Object evalShaHandleReloadScript(MethodContext context, List keys, List argv) {
        try {
            return jedis.evalsha(context.getSha1(), keys, argv);
        } catch (JedisDataException e) {
            if (e.getMessage() != null && e.getMessage().contains("NOSCRIPT")) {
                //If it throws again, we can back-off or we can just let it throw again. In this case, I think we should
                //let it throw because most likely will be trying the same thing again and hopefully it will succeed later.
                final String newSha = jedis.scriptLoad(context.getLuaContext().getRenderedLuaString());
                if (!newSha.equals(context.getSha1())) {
                    throw new IllegalStateException("sha should match but they did not");
                }
                return jedis.evalsha(context.getSha1(), keys, argv);
            } else {
                throw e;
            }
        }
    }
}