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Lucene example source code file (BooleanQueryNodeBuilder.java)

This example Lucene source code file (BooleanQueryNodeBuilder.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

booleanquery, booleanquery, booleanquerynode, booleanquerynodebuilder, mod_not, mod_req, modifierquerynode, modifierquerynode, object, query, query, querynode, querynodeexception, querynodeexception, util

The Lucene BooleanQueryNodeBuilder.java source code

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

/**
 * 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.messages.MessageImpl;
import org.apache.lucene.queryParser.core.QueryNodeException;
import org.apache.lucene.queryParser.core.builders.QueryTreeBuilder;
import org.apache.lucene.queryParser.core.messages.QueryParserMessages;
import org.apache.lucene.queryParser.core.nodes.BooleanQueryNode;
import org.apache.lucene.queryParser.core.nodes.ModifierQueryNode;
import org.apache.lucene.queryParser.core.nodes.QueryNode;
import org.apache.lucene.queryParser.standard.parser.EscapeQuerySyntaxImpl;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.BooleanQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.BooleanQuery.TooManyClauses;

/**
 * Builds a {@link BooleanQuery} object from a {@link BooleanQueryNode} object.
 * Every children in the {@link BooleanQueryNode} object must be already tagged
 * using {@link QueryTreeBuilder#QUERY_TREE_BUILDER_TAGID} with a {@link Query}
 * object. <br/>
 * <br/>
 * It takes in consideration if the children is a {@link ModifierQueryNode} to
 * define the {@link BooleanClause}.
 */
public class BooleanQueryNodeBuilder implements StandardQueryBuilder {

  public BooleanQueryNodeBuilder() {
    // empty constructor
  }

  public BooleanQuery build(QueryNode queryNode) throws QueryNodeException {
    BooleanQueryNode booleanNode = (BooleanQueryNode) queryNode;

    BooleanQuery bQuery = new BooleanQuery();
    List<QueryNode> children = booleanNode.getChildren();

    if (children != null) {

      for (QueryNode child : children) {
        Object obj = child.getTag(QueryTreeBuilder.QUERY_TREE_BUILDER_TAGID);

        if (obj != null) {
          Query query = (Query) obj;

          try {
            bQuery.add(query, getModifierValue(child));

          } catch (TooManyClauses ex) {

            throw new QueryNodeException(new MessageImpl(
                QueryParserMessages.TOO_MANY_BOOLEAN_CLAUSES, BooleanQuery
                    .getMaxClauseCount(), queryNode
                    .toQueryString(new EscapeQuerySyntaxImpl())), ex);

          }

        }

      }

    }

    return bQuery;

  }

  private static BooleanClause.Occur getModifierValue(QueryNode node)
      throws QueryNodeException {

    if (node instanceof ModifierQueryNode) {
      ModifierQueryNode mNode = ((ModifierQueryNode) node);
      switch (mNode.getModifier()) {

      case MOD_REQ:
        return BooleanClause.Occur.MUST;

      case MOD_NOT:
        return BooleanClause.Occur.MUST_NOT;

      case MOD_NONE:
        return BooleanClause.Occur.SHOULD;

      }

    }

    return BooleanClause.Occur.SHOULD;

  }

}

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