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Lucene example source code file (TermRangeQuery.java)

This example Lucene source code file (TermRangeQuery.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

collator, collator, filteredtermenum, io, ioexception, multitermquery, override, override, string, string, stringbuilder, termrangequery, termrangequery, termrangetermenum, text, to

The Lucene TermRangeQuery.java source code

package org.apache.lucene.search;

/**
 * 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.text.Collator;

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.util.ToStringUtils;

/**
 * A Query that matches documents within an range of terms.
 *
 * <p>This query matches the documents looking for terms that fall into the
 * supplied range according to {@link
 * String#compareTo(String)}, unless a <code>Collator is provided. It is not intended
 * for numerical ranges; use {@link NumericRangeQuery} instead.
 *
 * <p>This query uses the {@link
 * MultiTermQuery#CONSTANT_SCORE_AUTO_REWRITE_DEFAULT}
 * rewrite method.
 * @since 2.9
 */

public class TermRangeQuery extends MultiTermQuery {
  private String lowerTerm;
  private String upperTerm;
  private Collator collator;
  private String field;
  private boolean includeLower;
  private boolean includeUpper;


  /**
   * Constructs a query selecting all terms greater/equal than <code>lowerTerm
   * but less/equal than <code>upperTerm. 
   * 
   * <p>
   * If an endpoint is null, it is said 
   * to be "open". Either or both endpoints may be open.  Open endpoints may not 
   * be exclusive (you can't select all but the first or last term without 
   * explicitly specifying the term to exclude.)
   * 
   * @param field The field that holds both lower and upper terms.
   * @param lowerTerm
   *          The term text at the lower end of the range
   * @param upperTerm
   *          The term text at the upper end of the range
   * @param includeLower
   *          If true, the <code>lowerTerm is
   *          included in the range.
   * @param includeUpper
   *          If true, the <code>upperTerm is
   *          included in the range.
   */
  public TermRangeQuery(String field, String lowerTerm, String upperTerm, boolean includeLower, boolean includeUpper) {
    this(field, lowerTerm, upperTerm, includeLower, includeUpper, null);
  }

  /** Constructs a query selecting all terms greater/equal than
   * <code>lowerTerm but less/equal than upperTerm.
   * <p>
   * If an endpoint is null, it is said 
   * to be "open". Either or both endpoints may be open.  Open endpoints may not 
   * be exclusive (you can't select all but the first or last term without 
   * explicitly specifying the term to exclude.)
   * <p>
   * If <code>collator is not null, it will be used to decide whether
   * index terms are within the given range, rather than using the Unicode code
   * point order in which index terms are stored.
   * <p>
   * <strong>WARNING: Using this constructor and supplying a non-null
   * value in the <code>collator parameter will cause every single 
   * index Term in the Field referenced by lowerTerm and/or upperTerm to be
   * examined.  Depending on the number of index Terms in this Field, the 
   * operation could be very slow.
   *
   * @param lowerTerm The Term text at the lower end of the range
   * @param upperTerm The Term text at the upper end of the range
   * @param includeLower
   *          If true, the <code>lowerTerm is
   *          included in the range.
   * @param includeUpper
   *          If true, the <code>upperTerm is
   *          included in the range.
   * @param collator The collator to use to collate index Terms, to determine
   *  their membership in the range bounded by <code>lowerTerm and
   *  <code>upperTerm.
   */
  public TermRangeQuery(String field, String lowerTerm, String upperTerm, boolean includeLower, boolean includeUpper,
                    Collator collator) {
    this.field = field;
    this.lowerTerm = lowerTerm;
    this.upperTerm = upperTerm;
    this.includeLower = includeLower;
    this.includeUpper = includeUpper;
    this.collator = collator;
  }

  /** Returns the field name for this query */
  public String getField() { return field; }
  
  /** Returns the lower value of this range query */
  public String getLowerTerm() { return lowerTerm; }

  /** Returns the upper value of this range query */
  public String getUpperTerm() { return upperTerm; }
  
  /** Returns <code>true if the lower endpoint is inclusive */
  public boolean includesLower() { return includeLower; }
  
  /** Returns <code>true if the upper endpoint is inclusive */
  public boolean includesUpper() { return includeUpper; }

  /** Returns the collator used to determine range inclusion, if any. */
  public Collator getCollator() { return collator; }
  
  @Override
  protected FilteredTermEnum getEnum(IndexReader reader) throws IOException {
    return new TermRangeTermEnum(reader, field, lowerTerm,
        upperTerm, includeLower, includeUpper, collator);
  }

  /** Prints a user-readable version of this query. */
  @Override
  public String toString(String field) {
      StringBuilder buffer = new StringBuilder();
      if (!getField().equals(field)) {
          buffer.append(getField());
          buffer.append(":");
      }
      buffer.append(includeLower ? '[' : '{');
      buffer.append(lowerTerm != null ? lowerTerm : "*");
      buffer.append(" TO ");
      buffer.append(upperTerm != null ? upperTerm : "*");
      buffer.append(includeUpper ? ']' : '}');
      buffer.append(ToStringUtils.boost(getBoost()));
      return buffer.toString();
  }

  @Override
  public int hashCode() {
    final int prime = 31;
    int result = super.hashCode();
    result = prime * result + ((collator == null) ? 0 : collator.hashCode());
    result = prime * result + ((field == null) ? 0 : field.hashCode());
    result = prime * result + (includeLower ? 1231 : 1237);
    result = prime * result + (includeUpper ? 1231 : 1237);
    result = prime * result + ((lowerTerm == null) ? 0 : lowerTerm.hashCode());
    result = prime * result + ((upperTerm == null) ? 0 : upperTerm.hashCode());
    return result;
  }

  @Override
  public boolean equals(Object obj) {
    if (this == obj)
      return true;
    if (!super.equals(obj))
      return false;
    if (getClass() != obj.getClass())
      return false;
    TermRangeQuery other = (TermRangeQuery) obj;
    if (collator == null) {
      if (other.collator != null)
        return false;
    } else if (!collator.equals(other.collator))
      return false;
    if (field == null) {
      if (other.field != null)
        return false;
    } else if (!field.equals(other.field))
      return false;
    if (includeLower != other.includeLower)
      return false;
    if (includeUpper != other.includeUpper)
      return false;
    if (lowerTerm == null) {
      if (other.lowerTerm != null)
        return false;
    } else if (!lowerTerm.equals(other.lowerTerm))
      return false;
    if (upperTerm == null) {
      if (other.upperTerm != null)
        return false;
    } else if (!upperTerm.equals(other.upperTerm))
      return false;
    return true;
  }

}

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