content: package org.apache.solr.highlight;
  /**
   * 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.util.ArrayList;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Map;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.lucene.search.Query;
  import org.apache.solr.common.params.HighlightParams;
  import org.apache.solr.common.params.SolrParams;
  import org.apache.solr.common.util.NamedList;
  import org.apache.solr.core.SolrConfig;
  import org.apache.solr.request.SolrQueryRequest;
  import org.apache.solr.search.DocList;
  import org.apache.solr.util.SolrPluginUtils;
  
  public abstract class SolrHighlighter
  {
    public static Logger log = LoggerFactory.getLogger(SolrHighlighter.class);
  
    // Thread safe registry
    protected final Map<String,SolrFormatter> formatters =
      new HashMap<String, SolrFormatter>();
  
    // Thread safe registry
    protected final Map<String,SolrEncoder> encoders =
      new HashMap<String, SolrEncoder>();
  
    // Thread safe registry
    protected final Map<String,SolrFragmenter> fragmenters =
      new HashMap<String, SolrFragmenter>() ;
  
    // Thread safe registry
    protected final Map<String, SolrFragListBuilder> fragListBuilders =
      new HashMap<String, SolrFragListBuilder>() ;
  
    // Thread safe registry
    protected final Map<String, SolrFragmentsBuilder> fragmentsBuilders =
      new HashMap<String, SolrFragmentsBuilder>() ;
  
    // Thread safe registry
    protected final Map<String, SolrBoundaryScanner> boundaryScanners =
      new HashMap<String, SolrBoundaryScanner>() ;
  
    @Deprecated
    public abstract void initalize( SolrConfig config );
  
  
    /**
     * Check whether Highlighting is enabled for this request.
     * @param params The params controlling Highlighting
     * @return <code>true</code> if highlighting enabled, <code>false</code> if not.
     */
    public boolean isHighlightingEnabled(SolrParams params) {
      return params.getBool(HighlightParams.HIGHLIGHT, false);
    }
  
    /**
     * Return a String array of the fields to be highlighted.
     * Falls back to the programatic defaults, or the default search field if the list of fields
     * is not specified in either the handler configuration or the request.
     * @param query The current Query
     * @param request The current SolrQueryRequest
     * @param defaultFields Programmatic default highlight fields, used if nothing is specified in the handler config or the request.
     */
    public String[] getHighlightFields(Query query, SolrQueryRequest request, String[] defaultFields) {
      String fields[] = request.getParams().getParams(HighlightParams.FIELDS);
  
      // if no fields specified in the request, or the handler, fall back to programmatic default, or default search field.
      if(emptyArray(fields)) {
        // use default search field if highlight fieldlist not specified.
        if (emptyArray(defaultFields)) {
          String defaultSearchField = request.getSchema().getDefaultSearchFieldName();
          fields = null == defaultSearchField ? new String[]{} : new String[]{defaultSearchField};
        }
        else {
          fields = defaultFields;
        }
      }
      else if (fields.length == 1) {
        if (fields[0].contains("*")) {
          // create a Java regular expression from the wildcard string
          String fieldRegex = fields[0].replaceAll("\\*", ".*");
          Collection<String> storedHighlightFieldNames = request.getSearcher().getStoredHighlightFieldNames();
          List<String> storedFieldsToHighlight = new ArrayList<String>();
          for (String storedFieldName: storedHighlightFieldNames) {
              if (storedFieldName.matches(fieldRegex)) {
                storedFieldsToHighlight.add(storedFieldName);
              }
          }
          fields = storedFieldsToHighlight.toArray(new String[] {});
        } else {
          // if there's a single request/handler value, it may be a space/comma separated list
          fields = SolrPluginUtils.split(fields[0]);
        }
      }
  
      return fields;
    }
  
    protected boolean emptyArray(String[] arr) {
      return (arr == null || arr.length == 0 || arr[0] == null || arr[0].trim().length() == 0);
    }
  
    /**
     * Generates a list of Highlighted query fragments for each item in a list
     * of documents, or returns null if highlighting is disabled.
     *
     * @param docs query results
     * @param query the query
     * @param req the current request
     * @param defaultFields default list of fields to summarize
     *
     * @return NamedList containing a NamedList for each document, which in
     * turns contains sets (field, summary) pairs.
     */
    @SuppressWarnings("unchecked")
    public abstract NamedList<Object> doHighlighting(DocList docs, Query query, SolrQueryRequest req, String[] defaultFields) throws IOException;
  }
  