content: /**
   * 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.
   */
  
  package org.apache.solr.search.function;
  
  import org.apache.lucene.search.FieldCache;
  import org.apache.lucene.index.IndexReader;
  
  import java.io.IOException;
  
  /** Internal class, subject to change.
   *  Serves as base class for DocValues based on StringIndex 
   **/
  public abstract class StringIndexDocValues extends DocValues {
      protected final FieldCache.StringIndex index;
      protected final int[] order;
      protected final String[] lookup;
      protected final ValueSource vs;
  
      public StringIndexDocValues(ValueSource vs, IndexReader reader, String field) throws IOException {
        try {
          index = FieldCache.DEFAULT.getStringIndex(reader, field);
        } catch (RuntimeException e) {
          throw new StringIndexException(field, e);
        }
        order = index.order;
        lookup = index.lookup;
        this.vs = vs;
      }
    
      protected abstract String toTerm(String readableValue);
  
     @Override
      public ValueSourceScorer getRangeScorer(IndexReader reader, String lowerVal, String upperVal, boolean includeLower, boolean includeUpper) {
        // TODO: are lowerVal and upperVal in indexed form or not?
        lowerVal = lowerVal == null ? null : toTerm(lowerVal);
        upperVal = upperVal == null ? null : toTerm(upperVal);
  
       int lower = Integer.MIN_VALUE;
       if (lowerVal != null) {
         lower = index.binarySearchLookup(lowerVal);
         if (lower < 0) {
           lower = -lower-1;
         } else if (!includeLower) {
           lower++;
         }
       }
  
       int upper = Integer.MAX_VALUE;
       if (upperVal != null) {
         upper = index.binarySearchLookup(upperVal);
         if (upper < 0) {
           upper = -upper-2;
         } else if (!includeUpper) {
           upper--;
         }
       }
  
        final int ll = lower;
        final int uu = upper;
  
        return new ValueSourceScorer(reader, this) {
          @Override
          public boolean matchesValue(int doc) {
            int ord = order[doc];
            return ord >= ll && ord <= uu;
          }
        };
      }
  
      @Override
      public String toString(int doc) {
        return vs.description() + '=' + strVal(doc);
      }
  
    public static final class StringIndexException extends RuntimeException {
      public StringIndexException(final String fieldName,
                                  final RuntimeException cause) {
        super("Can't initialize StringIndex to generate (function) " +
              "DocValues for field: " + fieldName, cause);
      }
    }
    
  }
  