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Lucene example source code file (LowercaseExpandedTermsQueryNodeProcessor.java)

This example Lucene source code file (LowercaseExpandedTermsQueryNodeProcessor.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

fieldquerynode, fuzzyquerynode, list, lowercaseexpandedtermsquerynodeprocessor, lowercaseexpandedtermsquerynodeprocessor, override, override, parametricquerynode, querynode, querynode, querynodeexception, querynodeexception, querynodeprocessorimpl, util, wildcardquerynode

The Lucene LowercaseExpandedTermsQueryNodeProcessor.java source code

package org.apache.lucene.queryParser.standard.processors;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */

import java.util.List;

import org.apache.lucene.queryParser.core.QueryNodeException;
import org.apache.lucene.queryParser.core.config.QueryConfigHandler;
import org.apache.lucene.queryParser.core.nodes.FieldQueryNode;
import org.apache.lucene.queryParser.core.nodes.FuzzyQueryNode;
import org.apache.lucene.queryParser.core.nodes.ParametricQueryNode;
import org.apache.lucene.queryParser.core.nodes.QueryNode;
import org.apache.lucene.queryParser.core.processors.QueryNodeProcessorImpl;
import org.apache.lucene.queryParser.core.util.UnescapedCharSequence;
import org.apache.lucene.queryParser.standard.config.LowercaseExpandedTermsAttribute;
import org.apache.lucene.queryParser.standard.nodes.WildcardQueryNode;

/**
 * This processor verifies if the attribute
 * {@link LowercaseExpandedTermsAttribute} is defined in the
 * {@link QueryConfigHandler}. If it is and the expanded terms should be
 * lower-cased, it looks for every {@link WildcardQueryNode},
 * {@link FuzzyQueryNode} and {@link ParametricQueryNode} and lower-case its
 * term. <br/>
 * 
 * @see LowercaseExpandedTermsAttribute
 */
public class LowercaseExpandedTermsQueryNodeProcessor extends
    QueryNodeProcessorImpl {

  public LowercaseExpandedTermsQueryNodeProcessor() {
    // empty constructor
  }

  @Override
  public QueryNode process(QueryNode queryTree) throws QueryNodeException {

    if (getQueryConfigHandler().hasAttribute(
        LowercaseExpandedTermsAttribute.class)) {

      if (getQueryConfigHandler().getAttribute(
          LowercaseExpandedTermsAttribute.class).isLowercaseExpandedTerms()) {
        
        return super.process(queryTree);
        
      }

    }

    return queryTree;

  }

  @Override
  protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {

    if (node instanceof WildcardQueryNode || node instanceof FuzzyQueryNode
        || node instanceof ParametricQueryNode) {

      FieldQueryNode fieldNode = (FieldQueryNode) node;
      fieldNode.setText(UnescapedCharSequence.toLowerCase(fieldNode.getText()));
    }

    return node;

  }

  @Override
  protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {

    return node;

  }

  @Override
  protected List<QueryNode> setChildrenOrder(List children)
      throws QueryNodeException {

    return children;

  }

}

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