本文整理了Java中com.baidu.hugegraph.backend.query.Query.empty方法的一些代码示例，展示了Query.empty的具体用法。这些代码示例主要来源于Github/Stackoverflow/Maven等平台，是从一些精选项目中提取出来的代码，具有较强的参考意义，能在一定程度帮忙到你。Query.empty方法的具体详情如下：
包路径：com.baidu.hugegraph.backend.query.Query
类名称：Query
方法名：empty

Query.empty介绍

暂无

代码示例

代码示例来源：origin: hugegraph/hugegraph

@Override
protected Iterator<HugeEdge> queryEdgesFromBackend(Query query) {
  if (query.empty()) {
    // Query all edges, don't cache it
    return super.queryEdgesFromBackend(query);
  }
  Id id = new QueryId(query);
  @SuppressWarnings("unchecked")
  List<HugeEdge> edges = (List<HugeEdge>) this.edgesCache.get(id);
  if (edges == null) {
    // Iterator can't be cached, caching list instead
    edges = ImmutableList.copyOf(super.queryEdgesFromBackend(query));
    if (edges.size() <= MAX_CACHE_EDGES_PER_QUERY) {
      this.edgesCache.update(id, edges);
    }
  }
  return edges.iterator();
}

代码示例来源：origin: hugegraph/hugegraph

@Watched(prefix = "tx")
public Iterator<BackendEntry> query(Query query) {
  LOG.debug("Transaction query: {}", query);
  /*
   * NOTE: it's dangerous if an IdQuery/ConditionQuery is empty
   * check if the query is empty and its class is not the Query itself
   */
  if (query.empty() && !query.getClass().equals(Query.class)) {
    throw new BackendException("Query without any id or condition");
  }
  query = this.serializer.writeQuery(query);
  this.beforeRead();
  try {
    return this.store.query(query);
  } finally {
    this.afterRead(); // TODO: not complete the iteration currently
  }
}

代码示例来源：origin: hugegraph/hugegraph

@SuppressWarnings("unchecked")
@Override
public Iterator<BackendEntry> query(Query query) {
  if (query.empty()) {
    return this.store.query(query);
  }
  QueryId id = new QueryId(query);
  Object result = this.cache.get(id);
  if (result != null) {
    return (Iterator<BackendEntry>) result;
  } else {
    Iterator<BackendEntry> rs = this.store.query(query);
    if (rs.hasNext()) {
      this.cache.update(id, rs);
    }
    return rs;
  }
}

代码示例来源：origin: hugegraph/hugegraph

} else if (!q.empty()) {

代码示例来源：origin: hugegraph/hugegraph

if (query.empty()) {
  return newEntryIterator(this.queryAll(session, query), query);

代码示例来源：origin: hugegraph/hugegraph

if (query.empty()) {
  return newEntryIterator(this.queryAll(session, query), query);

代码示例来源：origin: com.baidu.hugegraph/hugegraph-core

@Override
protected Iterator<HugeEdge> queryEdgesFromBackend(Query query) {
  if (query.empty()) {
    // Query all edges, don't cache it
    return super.queryEdgesFromBackend(query);
  }
  Id id = new QueryId(query);
  @SuppressWarnings("unchecked")
  List<HugeEdge> edges = (List<HugeEdge>) this.edgesCache.get(id);
  if (edges == null) {
    // Iterator can't be cached, caching list instead
    edges = ImmutableList.copyOf(super.queryEdgesFromBackend(query));
    if (edges.size() <= MAX_CACHE_EDGES_PER_QUERY) {
      this.edgesCache.update(id, edges);
    }
  }
  return edges.iterator();
}

代码示例来源：origin: com.baidu.hugegraph/hugegraph-core

@Watched(prefix = "tx")
public Iterator<BackendEntry> query(Query query) {
  LOG.debug("Transaction query: {}", query);
  /*
   * NOTE: it's dangerous if an IdQuery/ConditionQuery is empty
   * check if the query is empty and its class is not the Query itself
   */
  if (query.empty() && !query.getClass().equals(Query.class)) {
    throw new BackendException("Query without any id or condition");
  }
  query = this.serializer.writeQuery(query);
  this.beforeRead();
  try {
    return this.store.query(query);
  } finally {
    this.afterRead(); // TODO: not complete the iteration currently
  }
}

代码示例来源：origin: com.baidu.hugegraph/hugegraph-core

@SuppressWarnings("unchecked")
@Override
public Iterator<BackendEntry> query(Query query) {
  if (query.empty()) {
    return this.store.query(query);
  }
  QueryId id = new QueryId(query);
  Object result = this.cache.get(id);
  if (result != null) {
    return (Iterator<BackendEntry>) result;
  } else {
    Iterator<BackendEntry> rs = this.store.query(query);
    if (rs.hasNext()) {
      this.cache.update(id, rs);
    }
    return rs;
  }
}

代码示例来源：origin: com.baidu.hugegraph/hugegraph-core

@Override
public Iterator<BackendEntry> query(Query query) {
  if (!(query instanceof ConditionQuery)) {
    return super.query(query);
  }
  List<Query> queries = new ArrayList<>();
  for (ConditionQuery cq: ConditionQueryFlatten.flatten(
              (ConditionQuery) query)) {
    Query q = this.optimizeQuery(cq);
    /*
     * NOTE: There are two possibilities for this query:
     * 1.sysprop-query, which would not be empty.
     * 2.index-query result(ids after optimization), which may be empty.
     */
    if (!q.empty()) {
      // Return empty if there is no result after index-query
      queries.add(q);
    }
  }
  ExtendableIterator<BackendEntry> rs = new ExtendableIterator<>();
  for (Query q : queries) {
    rs.extend(super.query(q));
  }
  return rs;
}

代码示例来源：origin: com.baidu.hugegraph/hugegraph-rocksdb

@Override
public Iterator<BackendEntry> query(Session session, Query query) {
  if (query.limit() == 0 && query.limit() != Query.NO_LIMIT) {
    LOG.debug("Return empty result(limit=0) for query {}", query);
    return ImmutableList.<BackendEntry>of().iterator();
  }
  // Query all
  if (query.empty()) {
    return newEntryIterator(this.queryAll(session, query), query);
  }
  // Query by id
  if (query.conditions().isEmpty()) {
    assert !query.ids().isEmpty();
    ExtendableIterator<BackendEntry> rs = new ExtendableIterator<>();
    for (Id id : query.ids()) {
      rs.extend(newEntryIterator(this.queryById(session, id), query));
    }
    return rs;
  }
  // Query by condition (or condition + id)
  ConditionQuery cq = (ConditionQuery) query;
  return newEntryIterator(this.queryByCond(session, cq), query);
}