1 package org.apache.lucene.queryParser.core.processors;
4 * Licensed to the Apache Software Foundation (ASF) under one or more
5 * contributor license agreements. See the NOTICE file distributed with
6 * this work for additional information regarding copyright ownership.
7 * The ASF licenses this file to You under the Apache License, Version 2.0
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9 * the License. You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
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20 import java.util.List;
22 import org.apache.lucene.queryParser.core.QueryNodeException;
23 import org.apache.lucene.queryParser.core.nodes.BooleanQueryNode;
24 import org.apache.lucene.queryParser.core.nodes.BoostQueryNode;
25 import org.apache.lucene.queryParser.core.nodes.DeletedQueryNode;
26 import org.apache.lucene.queryParser.core.nodes.MatchNoDocsQueryNode;
27 import org.apache.lucene.queryParser.core.nodes.ModifierQueryNode;
28 import org.apache.lucene.queryParser.core.nodes.QueryNode;
29 import org.apache.lucene.queryParser.core.nodes.TokenizedPhraseQueryNode;
33 * A {@link NoChildOptimizationQueryNodeProcessor} removes every
34 * BooleanQueryNode, BoostQueryNode, TokenizedPhraseQueryNode or
35 * ModifierQueryNode that do not have a valid children.
38 * Example: When the children of these nodes are removed for any reason then the
39 * nodes may become invalid.
42 public class NoChildOptimizationQueryNodeProcessor extends
43 QueryNodeProcessorImpl {
45 public NoChildOptimizationQueryNodeProcessor() {
50 protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {
52 if (node instanceof BooleanQueryNode || node instanceof BoostQueryNode
53 || node instanceof TokenizedPhraseQueryNode
54 || node instanceof ModifierQueryNode) {
56 List<QueryNode> children = node.getChildren();
58 if (children != null && children.size() > 0) {
60 for (QueryNode child : children) {
62 if (!(child instanceof DeletedQueryNode)) {
70 return new MatchNoDocsQueryNode();
79 protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {
86 protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
87 throws QueryNodeException {