content: package org.apache.lucene.analysis.synonym;
  
  /*
   * 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.analysis.Analyzer;
  import org.apache.lucene.util.CharsRef;
  import org.apache.lucene.util.CharsRefBuilder;
  
  import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.LineNumberReader;
  import java.io.Reader;
  import java.text.ParseException;
  import java.util.ArrayList;
  
  /**
   * Parser for the Solr synonyms format.
   * <ol>
   *   <li> Blank lines and lines starting with '#' are comments.
   *   <li> Explicit mappings match any token sequence on the LHS of "=&gt;"
   *        and replace with all alternatives on the RHS.  These types of mappings
   *        ignore the expand parameter in the constructor.
   *        Example:
   *        <blockquote>i-pod, i pod =&gt; ipod</blockquote>
   *   <li> Equivalent synonyms may be separated with commas and give
   *        no explicit mapping.  In this case the mapping behavior will
   *        be taken from the expand parameter in the constructor.  This allows
   *        the same synonym file to be used in different synonym handling strategies.
   *        Example:
   *        <blockquote>ipod, i-pod, i pod</blockquote>
   *
   *   <li> Multiple synonym mapping entries are merged.
   *        Example:
   *        <blockquote>
   *         foo =&gt; foo bar
   *         foo =&gt; baz
   *         is equivalent to
   *         foo =&gt; foo bar, baz
   *        </blockquote>
   *  </ol>
   *
   * @lucene.experimental
   */
  public class NewSolrSynonymParser extends NewSynonymFilterFactory.SynonymParser {
      private final boolean expand;
  
      public NewSolrSynonymParser(boolean dedup, boolean expand, Analyzer analyzer) {
          super(dedup, analyzer);
          this.expand = expand;
      }
  
      public void add(Reader in) throws IOException, ParseException {
          LineNumberReader br = new LineNumberReader(in);
          try {
              addInternal(br);
          } catch (IllegalArgumentException e) {
              ParseException ex = new ParseException("Invalid synonym rule at line " + br.getLineNumber(), 0);
              ex.initCause(e);
              throw ex;
          } finally {
              br.close();
          }
      }
  
      private void addInternal(BufferedReader in) throws IOException {
          String line = null;
          while ((line = in.readLine()) != null) {
              if (line.length() == 0 || line.charAt(0) == '#') {
                  continue; // ignore empty lines and comments
              }
  
              CharsRef[] inputs;
              CharsRef[] outputs;
  
              // TODO: we could process this more efficiently.
              String[] sides = split(line, "=>");
              if (sides.length > 1) { // explicit mapping
                  if (sides.length != 2) {
                      throw new IllegalArgumentException("more than one explicit mapping specified on the same line");
                  }
                  String[] inputStrings = split(sides[0], ",");
                  inputs = new CharsRef[inputStrings.length];
                  for (int i = 0; i < inputs.length; i++) {
                      inputs[i] = analyze(unescape(inputStrings[i]).trim(), new CharsRefBuilder());
                  }
  
                  String[] outputStrings = split(sides[1], ",");
                  outputs = new CharsRef[outputStrings.length];
                  for (int i = 0; i < outputs.length; i++) {
                      outputs[i] = analyze(unescape(outputStrings[i]).trim(), new CharsRefBuilder());
                  }
              } else {
                  String[] inputStrings = split(line, ",");
                  inputs = new CharsRef[inputStrings.length];
                  for (int i = 0; i < inputs.length; i++) {
                      inputs[i] = analyze(unescape(inputStrings[i]).trim(), new CharsRefBuilder());
                  }
                  if (expand) {
                      outputs = inputs;
                  } else {
                      outputs = new CharsRef[1];
                      outputs[0] = inputs[0];
                  }
              }
  
              // currently we include the term itself in the map,
              // and use includeOrig = false always.
              // this is how the existing filter does it, but its actually a bug,
              // especially if combined with ignoreCase = true
              for (int i = 0; i < inputs.length; i++) {
                  for (int j = 0; j < outputs.length; j++) {
                      add(inputs[i], outputs[j], false);
                  }
              }
          }
      }
  
      private static String[] split(String s, String separator) {
          ArrayList<String> list = new ArrayList<String>(2);
          StringBuilder sb = new StringBuilder();
          int pos = 0, end = s.length();
          while (pos < end) {
              if (s.startsWith(separator, pos)) {
                  if (sb.length() > 0) {
                      list.add(sb.toString());
                      sb = new StringBuilder();
                  }
                  pos += separator.length();
                  continue;
              }
  
              char ch = s.charAt(pos++);
              if (ch == '\\') {
                  sb.append(ch);
                  if (pos >= end) break;  // ERROR, or let it go?
                  ch = s.charAt(pos++);
              }
  
              sb.append(ch);
          }
  
          if (sb.length() > 0) {
              list.add(sb.toString());
          }
  
          return list.toArray(new String[list.size()]);
      }
  
      private String unescape(String s) {
          if (s.indexOf("\\") >= 0) {
              StringBuilder sb = new StringBuilder();
              for (int i = 0; i < s.length(); i++) {
                  char ch = s.charAt(i);
                  if (ch == '\\' && i < s.length() - 1) {
                      sb.append(s.charAt(++i));
                  } else {
                      sb.append(ch);
                  }
              }
              return sb.toString();
          }
          return s;
      }
  }
  