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package org.apache.lucene.queryParser.standard.processors;
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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import java.util.LinkedList;
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import java.util.List;
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import org.apache.lucene.queryParser.core.QueryNodeException;
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import org.apache.lucene.queryParser.core.config.QueryConfigHandler;
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import org.apache.lucene.queryParser.core.nodes.BooleanQueryNode;
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import org.apache.lucene.queryParser.core.nodes.FieldableNode;
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import org.apache.lucene.queryParser.core.nodes.GroupQueryNode;
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import org.apache.lucene.queryParser.core.nodes.QueryNode;
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import org.apache.lucene.queryParser.core.processors.QueryNodeProcessorImpl;
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import org.apache.lucene.queryParser.standard.config.StandardQueryConfigHandler.ConfigurationKeys;
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* This processor is used to expand terms so the query looks for the same term
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* in different fields. It also boosts a query based on its field. <br/>
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* This processor looks for every {@link FieldableNode} contained in the query
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* node tree. If a {@link FieldableNode} is found, it checks if there is a
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* {@link ConfigurationKeys#MULTI_FIELDS} defined in the {@link QueryConfigHandler}. If
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* there is, the {@link FieldableNode} is cloned N times and the clones are
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* added to a {@link BooleanQueryNode} together with the original node. N is
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* defined by the number of fields that it will be expanded to. The
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* {@link BooleanQueryNode} is returned. <br/>
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* @see ConfigurationKeys#MULTI_FIELDS
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public class MultiFieldQueryNodeProcessor extends QueryNodeProcessorImpl {
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private boolean processChildren = true;
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public MultiFieldQueryNodeProcessor() {
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protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {
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protected void processChildren(QueryNode queryTree) throws QueryNodeException {
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if (this.processChildren) {
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super.processChildren(queryTree);
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this.processChildren = true;
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protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {
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if (node instanceof FieldableNode) {
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this.processChildren = false;
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FieldableNode fieldNode = (FieldableNode) node;
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if (fieldNode.getField() == null) {
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CharSequence[] fields = getQueryConfigHandler().get(ConfigurationKeys.MULTI_FIELDS);
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throw new IllegalArgumentException(
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"StandardQueryConfigHandler.ConfigurationKeys.MULTI_FIELDS should be set on the QueryConfigHandler");
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if (fields != null && fields.length > 0) {
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fieldNode.setField(fields[0]);
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if (fields.length == 1) {
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LinkedList<QueryNode> children = new LinkedList<QueryNode>();
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children.add(fieldNode);
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for (int i = 1; i < fields.length; i++) {
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fieldNode = (FieldableNode) fieldNode.cloneTree();
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fieldNode.setField(fields[i]);
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children.add(fieldNode);
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} catch (CloneNotSupportedException e) {
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// should never happen
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return new GroupQueryNode(new BooleanQueryNode(children));
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protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
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throws QueryNodeException {