package org.apache.lucene.analysis.path;

/*
 * 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.Reader;
import java.util.Map;

import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.util.TokenizerFactory;
import org.apache.lucene.util.AttributeSource.AttributeFactory;

/**
 * Factory for {@link PathHierarchyTokenizer}. 
 * <p>
 * This factory is typically configured for use only in the <code>index</code> 
 * Analyzer (or only in the <code>query</code> Analyzer, but never both).
 * </p>
 * <p>
 * For example, in the configuration below a query for 
 * <code>Books/NonFic</code> will match documents indexed with values like 
 * <code>Books/NonFic</code>, <code>Books/NonFic/Law</code>, 
 * <code>Books/NonFic/Science/Physics</code>, etc. But it will not match 
 * documents indexed with values like <code>Books</code>, or 
 * <code>Books/Fic</code>...
 * </p>
 *
 * <pre class="prettyprint">
 * &lt;fieldType name="descendent_path" class="solr.TextField"&gt;
 *   &lt;analyzer type="index"&gt;
 *     &lt;tokenizer class="solr.PathHierarchyTokenizerFactory" delimiter="/" /&gt;
 *   &lt;/analyzer&gt;
 *   &lt;analyzer type="query"&gt;
 *     &lt;tokenizer class="solr.KeywordTokenizerFactory" /&gt;
 *   &lt;/analyzer&gt;
 * &lt;/fieldType&gt;
 * </pre>
 * <p>
 * In this example however we see the oposite configuration, so that a query 
 * for <code>Books/NonFic/Science/Physics</code> would match documents 
 * containing <code>Books/NonFic</code>, <code>Books/NonFic/Science</code>, 
 * or <code>Books/NonFic/Science/Physics</code>, but not 
 * <code>Books/NonFic/Science/Physics/Theory</code> or 
 * <code>Books/NonFic/Law</code>.
 * </p>
 * <pre class="prettyprint">
 * &lt;fieldType name="descendent_path" class="solr.TextField"&gt;
 *   &lt;analyzer type="index"&gt;
 *     &lt;tokenizer class="solr.KeywordTokenizerFactory" /&gt;
 *   &lt;/analyzer&gt;
 *   &lt;analyzer type="query"&gt;
 *     &lt;tokenizer class="solr.PathHierarchyTokenizerFactory" delimiter="/" /&gt;
 *   &lt;/analyzer&gt;
 * &lt;/fieldType&gt;
 * </pre>
 */
public class PathHierarchyTokenizerFactory extends TokenizerFactory {
  private final char delimiter;
  private final char replacement;
  private final boolean reverse;
  private final int skip;
  
  /** Creates a new PathHierarchyTokenizerFactory */
  public PathHierarchyTokenizerFactory(Map<String,String> args) {
    super(args);
    delimiter = getChar(args, "delimiter", PathHierarchyTokenizer.DEFAULT_DELIMITER);
    replacement = getChar(args, "replace", delimiter);
    reverse = getBoolean(args, "reverse", false);
    skip = getInt(args, "skip", PathHierarchyTokenizer.DEFAULT_SKIP);
    if (!args.isEmpty()) {
      throw new IllegalArgumentException("Unknown parameters: " + args);
    }
  }
  
  @Override
  public Tokenizer create(AttributeFactory factory, Reader input) {
    if (reverse) {
      return new ReversePathHierarchyTokenizer(factory, input, delimiter, replacement, skip);
    }
    return new PathHierarchyTokenizer(factory, input, delimiter, replacement, skip);
  }
}


