content: package org.apache.lucene.search.function;
  
  /**
   * 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.index.IndexReader;
  import org.apache.lucene.search.FieldCache;
  import org.apache.lucene.search.function.DocValues;
  
  import java.io.IOException;
  
  /**
   * Expert: obtains float field values from the 
   * {@link org.apache.lucene.search.FieldCache FieldCache}
   * using <code>getFloats()</code> and makes those values 
   * available as other numeric types, casting as needed.
   * 
   * @lucene.experimental
   * 
   * @see org.apache.lucene.search.function.FieldCacheSource for requirements 
   * on the field.
   *
   * <p><b>NOTE</b>: with the switch in 2.9 to segment-based
   * searching, if {@link #getValues} is invoked with a
   * composite (multi-segment) reader, this can easily cause
   * double RAM usage for the values in the FieldCache.  It's
   * best to switch your application to pass only atomic
   * (single segment) readers to this API.</p>
   */
  public class FloatFieldSource extends FieldCacheSource {
    private FieldCache.FloatParser parser;
  
    /**
     * Create a cached float field source with default string-to-float parser. 
     */
    public FloatFieldSource(String field) {
      this(field, null);
    }
  
    /**
     * Create a cached float field source with a specific string-to-float parser. 
     */
    public FloatFieldSource(String field, FieldCache.FloatParser parser) {
      super(field);
      this.parser = parser;
    }
  
    /*(non-Javadoc) @see org.apache.lucene.search.function.ValueSource#description() */
    @Override
    public String description() {
      return "float(" + super.description() + ')';
    }
  
    /*(non-Javadoc) @see org.apache.lucene.search.function.FieldCacheSource#getCachedValues(org.apache.lucene.search.FieldCache, java.lang.String, org.apache.lucene.index.IndexReader) */
    @Override
    public DocValues getCachedFieldValues (FieldCache cache, String field, IndexReader reader) throws IOException {
      final float[] arr = cache.getFloats(reader, field, parser);
      return new DocValues() {
        /*(non-Javadoc) @see org.apache.lucene.search.function.DocValues#floatVal(int) */
        @Override
        public float floatVal(int doc) {
          return arr[doc];      
        }
        /*(non-Javadoc) @see org.apache.lucene.search.function.DocValues#toString(int) */
        @Override
        public String toString(int doc) { 
          return  description() + '=' + arr[doc];  
        }
        /*(non-Javadoc) @see org.apache.lucene.search.function.DocValues#getInnerArray() */
        @Override
        Object getInnerArray() {
          return arr;
        }
      };
    }
  
    /*(non-Javadoc) @see org.apache.lucene.search.function.FieldCacheSource#cachedFieldSourceEquals(org.apache.lucene.search.function.FieldCacheSource) */
    @Override
    public boolean cachedFieldSourceEquals(FieldCacheSource o) {
      if (o.getClass() !=  FloatFieldSource.class) {
        return false;
      }
      FloatFieldSource other = (FloatFieldSource)o;
      return this.parser==null ? 
        other.parser==null :
        this.parser.getClass() == other.parser.getClass();
    }
  
    /*(non-Javadoc) @see org.apache.lucene.search.function.FieldCacheSource#cachedFieldSourceHashCode() */
    @Override
    public int cachedFieldSourceHashCode() {
      return parser==null ? 
        Float.class.hashCode() : parser.getClass().hashCode();
    }
  }