package utils;

import io.ebean.Ebean;
import io.ebean.Transaction;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;

import java.lang.reflect.Method;

/**
 * @author James Lin
 */
public class EbeanTransactionalInterceptor implements MethodInterceptor {

    private static final ThreadLocal<Integer> txCountLocal = ThreadLocal.withInitial(() -> 0);

    @Override
    public Object invoke(MethodInvocation invocation) throws Throwable {
        Method method = invocation.getMethod();
        Transactional annotation = method.getAnnotation(Transactional.class);
        boolean readOnly = annotation.readOnly();
        String dbName = annotation.dbName().name().toLowerCase();

        int txCount = txCountLocal.get();
        if(txCount == 0) {
            txCountLocal.set(++txCount);
            Transaction tx = null;
            try {
                tx = Ebean.getServer(dbName).beginTransaction();
                tx.getConnection().setAutoCommit(false);
                tx.setReadOnly(readOnly);
                Object result = invocation.proceed();
                tx.commit();
                return result;
            }
            finally {
                txCountLocal.remove();
                if(tx != null) {
                    tx.end();
                }
            }
        }
        else {
            txCountLocal.set(++txCount);
            try {
                return invocation.proceed();
            }
            finally {
                txCountLocal.set(--txCount);
            }
        }
    }
}

package utils;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * @author James Lin
 */
@Target({ElementType.TYPE, ElementType.METHOD})
@Retention(RetentionPolicy.RUNTIME)
public @interface Transactional {

    boolean readOnly() default false;
}