Java tutorial
/* * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package io.prestosql.sql.util; import com.google.common.graph.SuccessorsFunction; import com.google.common.graph.Traverser; import io.prestosql.sql.tree.Node; import java.util.stream.Stream; import static com.google.common.collect.Streams.stream; import static java.util.Objects.requireNonNull; public final class AstUtils { public static boolean nodeContains(Node node, Node subNode) { requireNonNull(node, "node is null"); requireNonNull(subNode, "subNode is null"); return preOrder(node).anyMatch(childNode -> childNode == subNode); } public static Stream<Node> preOrder(Node node) { return stream(Traverser.forTree((SuccessorsFunction<Node>) Node::getChildren) .depthFirstPreOrder(requireNonNull(node, "node is null"))); } private AstUtils() { } }