Lucene example source code file (SpanPayloadCheckQuery.java)

This example Lucene source code file (SpanPayloadCheckQuery.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

collection, collection, io, ioexception, iterator, object, override, override, spannearquery, spanpayloadcheckquery, spanpayloadcheckquery, spanpositioncheckquery, string, stringbuilder, stringbuilder, util

The Lucene SpanPayloadCheckQuery.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;
import java.util.Arrays;
import java.util.Collection;
import java.util.Iterator;


/**
 *   Only return those matches that have a specific payload at
 *  the given position.
 *<p/>
 * Do not use this with an SpanQuery that contains a {@link org.apache.lucene.search.spans.SpanNearQuery}.  Instead, use
 * {@link SpanNearPayloadCheckQuery} since it properly handles the fact that payloads
 * aren't ordered by {@link org.apache.lucene.search.spans.SpanNearQuery}.
 *
 **/
public class SpanPayloadCheckQuery extends SpanPositionCheckQuery{
  protected final Collection<byte[]> payloadToMatch;

  /**
   *
   * @param match The underlying {@link org.apache.lucene.search.spans.SpanQuery} to check
   * @param payloadToMatch The {@link java.util.Collection} of payloads to match
   */
  public SpanPayloadCheckQuery(SpanQuery match, Collection<byte[]> payloadToMatch) {
    super(match);
    if (match instanceof SpanNearQuery){
      throw new IllegalArgumentException("SpanNearQuery not allowed");
    }
    this.payloadToMatch = payloadToMatch;
  }

  @Override
  protected AcceptStatus acceptPosition(Spans spans) throws IOException {
    boolean result = spans.isPayloadAvailable();
    if (result == true){
      Collection<byte[]> candidate = spans.getPayload();
      if (candidate.size() == payloadToMatch.size()){
        //TODO: check the byte arrays are the same
        Iterator<byte[]> toMatchIter = payloadToMatch.iterator();
        //check each of the byte arrays, in order
        //hmm, can't rely on order here
        for (byte[] candBytes : candidate) {
          //if one is a mismatch, then return false
          if (Arrays.equals(candBytes, toMatchIter.next()) == false){
            return AcceptStatus.NO;
          }
        }
        //we've verified all the bytes
        return AcceptStatus.YES;
      } else {
        return AcceptStatus.NO;
      }
    }
    return AcceptStatus.YES;
  } 

  @Override
  public String toString(String field) {
    StringBuilder buffer = new StringBuilder();
    buffer.append("spanPayCheck(");
    buffer.append(match.toString(field));
    buffer.append(", payloadRef: ");
    for (byte[] bytes : payloadToMatch) {
      ToStringUtils.byteArray(buffer, bytes);
      buffer.append(';');
    }
    buffer.append(")");
    buffer.append(ToStringUtils.boost(getBoost()));
    return buffer.toString();
  }

  @Override
  public Object clone() {
    SpanPayloadCheckQuery result = new SpanPayloadCheckQuery((SpanQuery) match.clone(), payloadToMatch);
    result.setBoost(getBoost());
    return result;
  }

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

    SpanPayloadCheckQuery other = (SpanPayloadCheckQuery)o;
    return this.payloadToMatch.equals(other.payloadToMatch)
         && this.match.equals(other.match)
         && this.getBoost() == other.getBoost();
  }

  @Override
  public int hashCode() {
    int h = match.hashCode();
    h ^= (h << 8) | (h >>> 25);  // reversible
    //TODO: is this right?
    h ^= payloadToMatch.hashCode();
    h ^= Float.floatToRawIntBits(getBoost()) ;
    return h;
  }
}