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.highlight;
  
  import org.apache.lucene.search.vectorhighlight.BoundaryScanner;
  import org.apache.lucene.search.vectorhighlight.FragmentsBuilder;
  import org.apache.solr.common.SolrException;
  import org.apache.solr.common.params.DefaultSolrParams;
  import org.apache.solr.common.params.HighlightParams;
  import org.apache.solr.common.params.SolrParams;
  import org.apache.solr.core.SolrInfoMBean;
  import org.apache.solr.util.plugin.NamedListInitializedPlugin;
  
  public abstract class SolrFragmentsBuilder extends HighlightingPluginBase
    implements SolrInfoMBean, NamedListInitializedPlugin {
    
    public static final String DEFAULT_PRE_TAGS = "<em>";
    public static final String DEFAULT_POST_TAGS = "</em>";
  
    /**
     * Return a {@link org.apache.lucene.search.vectorhighlight.FragmentsBuilder} appropriate for this field.
     * 
     * @param params The params controlling Highlighting
     * @return An appropriate {@link org.apache.lucene.search.vectorhighlight.FragmentsBuilder}.
     */
    public FragmentsBuilder getFragmentsBuilder(SolrParams params, BoundaryScanner bs) {
      numRequests++;
      if( defaults != null ) {
        params = new DefaultSolrParams( params, defaults );
      }
      return getFragmentsBuilder( params, getPreTags( params, null ), getPostTags( params, null ), bs );
    }
    
    public String[] getPreTags( SolrParams params, String fieldName ){
      return getTags( params, HighlightParams.TAG_PRE, fieldName, DEFAULT_PRE_TAGS );
    }
    
    public String[] getPostTags( SolrParams params, String fieldName ){
      return getTags( params, HighlightParams.TAG_POST, fieldName, DEFAULT_POST_TAGS );
    }
    
    private String[] getTags( SolrParams params, String paramName, String fieldName, String def ){
      if( defaults != null ) {
        params = new DefaultSolrParams( params, defaults );
      }
      String value = null;
      if( fieldName == null )
        value = params.get( paramName, def );
      else
        value = params.getFieldParam( fieldName, paramName, def );
      String[] tags = value.split( "," );
      for( int i = 0; i < tags.length; i++ ){
        tags[i] = tags[i].trim();
      }
      return tags;
    }
    
    protected abstract FragmentsBuilder getFragmentsBuilder( SolrParams params,
        String[] preTags, String[] postTags, BoundaryScanner bs );
    
    protected char getMultiValuedSeparatorChar( SolrParams params ){
      String separator = params.get( HighlightParams.MULTI_VALUED_SEPARATOR, " " );
      if( separator.length() > 1 ){
        throw new SolrException( SolrException.ErrorCode.BAD_REQUEST,
            HighlightParams.MULTI_VALUED_SEPARATOR + " parameter must be a char, but is \"" + separator + "\"" );
      }
      return separator.charAt( 0 );
    }
  }
  