Lucene example source code file (SpanFirstQuery.java)

This example Lucene source code file (SpanFirstQuery.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

acceptstatus, io, ioexception, object, object, override, override, spanfirstquery, spanfirstquery, spanpositionrangequery, string, stringbuilder, stringbuilder

The Lucene SpanFirstQuery.java source code

package org.apache.lucene.search.spans;

/**
 * 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 org.apache.lucene.util.ToStringUtils;

import java.io.IOException;

/** Matches spans near the beginning of a field.
 * <p/> 
 * This class is a simple extension of {@link SpanPositionRangeQuery} in that it assumes the
 * start to be zero and only checks the end boundary.
 *
 *
 *  */
public class SpanFirstQuery extends SpanPositionRangeQuery {

  /** Construct a SpanFirstQuery matching spans in <code>match whose end
   * position is less than or equal to <code>end. */
  public SpanFirstQuery(SpanQuery match, int end) {
    super(match, 0, end);
  }

  @Override
  protected AcceptStatus acceptPosition(Spans spans) throws IOException {
    assert spans.start() != spans.end();
    if (spans.start() >= end)
      return AcceptStatus.NO_AND_ADVANCE;
    else if (spans.end() <= end)
      return AcceptStatus.YES;
    else
      return AcceptStatus.NO;
  }


  @Override
  public String toString(String field) {
    StringBuilder buffer = new StringBuilder();
    buffer.append("spanFirst(");
    buffer.append(match.toString(field));
    buffer.append(", ");
    buffer.append(end);
    buffer.append(")");
    buffer.append(ToStringUtils.boost(getBoost()));
    return buffer.toString();
  }

  @Override
  public Object clone() {
    SpanFirstQuery spanFirstQuery = new SpanFirstQuery((SpanQuery) match.clone(), end);
    spanFirstQuery.setBoost(getBoost());
    return spanFirstQuery;
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) return true;
    if (!(o instanceof SpanFirstQuery)) return false;

    SpanFirstQuery other = (SpanFirstQuery)o;
    return this.end == other.end
         && this.match.equals(other.match)
         && this.getBoost() == other.getBoost();
  }

  @Override
  public int hashCode() {
    int h = match.hashCode();
    h ^= (h << 8) | (h >>> 25);  // reversible
    h ^= Float.floatToRawIntBits(getBoost()) ^ end;
    return h;
  }


}