Lucene example source code file (SimpleTerm.java)

This example Lucene source code file (SimpleTerm.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

arraylist, distancesubquery, indexreader, io, ioexception, ioexception, matchingtermvisitor, matchingtermvisitor, override, override, query, simpleterm, string, string, stringbuilder, util

The Lucene SimpleTerm.java source code

package org.apache.lucene.queryParser.surround.query;
/**
 * 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.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.BooleanClause;
import org.apache.lucene.search.Query;

public abstract class SimpleTerm
  extends SrndQuery
  implements DistanceSubQuery, Comparable<SimpleTerm>
{
  public SimpleTerm(boolean q) {quoted = q;}
  
  private boolean quoted;
  boolean isQuoted() {return quoted;}
  
  public String getQuote() {return "\"";}
  public String getFieldOperator() {return "/";}
  
  public abstract String toStringUnquoted();
  
  public int compareTo(SimpleTerm ost) {
    /* for ordering terms and prefixes before using an index, not used */
    return this.toStringUnquoted().compareTo( ost.toStringUnquoted());
  }
  
  protected void suffixToString(StringBuilder r) {} /* override for prefix query */
  
  @Override
  public String toString() {
    StringBuilder r = new StringBuilder();
    if (isQuoted()) {
      r.append(getQuote());
    }
    r.append(toStringUnquoted());
    if (isQuoted()) {
      r.append(getQuote());
    }
    suffixToString(r);
    weightToString(r);
    return r.toString();
  }
  
  public abstract void visitMatchingTerms(
                            IndexReader reader,
                            String fieldName,
                            MatchingTermVisitor mtv) throws IOException;
  
  public interface MatchingTermVisitor {
    void visitMatchingTerm(Term t)throws IOException;
  }

  public String distanceSubQueryNotAllowed() {return null;}

  
  @Override
  public Query makeLuceneQueryFieldNoBoost(final String fieldName, final BasicQueryFactory qf) {
    return new Query() {
      @Override
      public String toString(String fn) {
        return getClass().toString() + " " + fieldName + " (" + fn + "?)";
      }
      
      @Override
      public Query rewrite(IndexReader reader) throws IOException {
        final List<Query> luceneSubQueries = new ArrayList();
        visitMatchingTerms( reader, fieldName,
            new MatchingTermVisitor() {
              public void visitMatchingTerm(Term term) throws IOException {
                luceneSubQueries.add(qf.newTermQuery(term));
              }
            });
        return  (luceneSubQueries.size() == 0) ? SrndQuery.theEmptyLcnQuery
              : (luceneSubQueries.size() == 1) ? luceneSubQueries.get(0)
              : SrndBooleanQuery.makeBooleanQuery(
                  /* luceneSubQueries all have default weight */
                  luceneSubQueries, BooleanClause.Occur.SHOULD); /* OR the subquery terms */ 
      }
    };
  }
    
  public void addSpanQueries(final SpanNearClauseFactory sncf) throws IOException {
    visitMatchingTerms(
          sncf.getIndexReader(),
          sncf.getFieldName(),
          new MatchingTermVisitor() {
            public void visitMatchingTerm(Term term) throws IOException {
              sncf.addTermWeighted(term, getWeight());
            }
          });
  }
}