Examples with Dialect com.github.walker.mybatis.paginator.dialect.Dialect used on opensource projects

Example 1 with Dialect

use of com.github.walker.mybatis.paginator.dialect.Dialect in project mybatis-paginator by HuQingmiao.

the class OffsetLimitInterceptor method intercept.

public Object intercept(final Invocation invocation) throws Throwable {
    final Executor executor = (Executor) invocation.getTarget();
    final Object[] queryArgs = invocation.getArgs();
    final MappedStatement ms = (MappedStatement) queryArgs[MAPPED_STATEMENT_INDEX];
    final Object parameter = queryArgs[PARAMETER_INDEX];
    final RowBounds rowBounds = (RowBounds) queryArgs[ROWBOUNDS_INDEX];
    //DAO接口中没有传PageBounds参量
    if (!(rowBounds instanceof PageBounds)) {
        return invocation.proceed();
    }
    //DAO接口传有PageBounds参量
    PageBounds pageBounds = (PageBounds) rowBounds;
    if (pageBounds.notValid()) {
        return new PageList((List) invocation.proceed());
    }
    final Dialect dialect;
    try {
        Class clazz = Class.forName(dialectClass);
        Constructor constructor = clazz.getConstructor(MappedStatement.class, Object.class, PageBounds.class);
        dialect = (Dialect) constructor.newInstance(new Object[] { ms, parameter, pageBounds });
    } catch (Exception e) {
        throw new ClassNotFoundException("Cannot create dialect instance: " + dialectClass, e);
    }
    final BoundSql boundSql = ms.getBoundSql(parameter);
    queryArgs[MAPPED_STATEMENT_INDEX] = copyFromNewSql(ms, boundSql, dialect.getPageSQL(), dialect.getParameterMappings(), dialect.getParameterObject());
    queryArgs[PARAMETER_INDEX] = dialect.getParameterObject();
    queryArgs[ROWBOUNDS_INDEX] = new RowBounds();
    //采用同步方式，执行分页查询
    //修复bug: 提交后台线程破坏了spring 事务管理，参见TransactionSynchronizationManager
    Callable<List> queryThread = new Callable<List>() {

        public List call() throws Exception {
            return (List) invocation.proceed();
        }
    };
    Future<List> queryFuture = call(queryThread, false);
    //如果不需要count总的结果集，则直接返回分页查询结果
    if (!pageBounds.isIfCount()) {
        return new PageList(queryFuture.get());
    }
    //对总的结果集进行count
    Callable<Integer> countThread = new Callable<Integer>() {

        public Integer call() throws Exception {
            Cache cache = ms.getCache();
            Integer count = null;
            if (cache != null && ms.isUseCache() && ms.getConfiguration().isCacheEnabled()) {
                CacheKey cacheKey = executor.createCacheKey(ms, parameter, new RowBounds(), copyFromBoundSql(ms, boundSql, dialect.getCountSQL(), boundSql.getParameterMappings(), boundSql.getParameterObject()));
                count = (Integer) cache.getObject(cacheKey);
                if (count == null) {
                    count = SQLHelp.getCount(ms, parameter, boundSql, dialect);
                    cache.putObject(cacheKey, count);
                }
            } else {
                count = SQLHelp.getCount(ms, parameter, boundSql, dialect);
            }
            return count;
        }
    };
    Future<Integer> countFutrue = call(countThread, false);
    return new PageList(queryFuture.get(), countFutrue.get().intValue());
}