Lucene example source code file (RBBIRuleCompiler.java)

This example Lucene source code file (RBBIRuleCompiler.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Lucene tags/keywords

bufferedreader, compiling, exception, file, file, fileoutputstream, inputstream, io, ioexception, ioexception, string, string, stringbuilder, stringbuilder, utf-8

The Lucene RBBIRuleCompiler.java source code

package org.apache.lucene.analysis.icu;

/**
 * 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.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

import com.ibm.icu.text.RuleBasedBreakIterator;

/**
 * Command-line utility to converts RuleBasedBreakIterator (.rbbi) files into
 * binary compiled form (.brk).
 */
public class RBBIRuleCompiler {
  
  static String getRules(File ruleFile) throws IOException {
    StringBuilder rules = new StringBuilder();
    InputStream in = new FileInputStream(ruleFile);
    BufferedReader cin = new BufferedReader(new InputStreamReader(in, "UTF-8"));
    String line = null;
    while ((line = cin.readLine()) != null) {
      if (!line.startsWith("#"))
        rules.append(line);
      rules.append('\n');
    }
    cin.close();
    in.close();
    return rules.toString();
  }
  
  static void compile(File srcDir, File destDir) throws Exception {
    File files[] = srcDir.listFiles(new FilenameFilter() {
      public boolean accept(File dir, String name) {
        return name.endsWith("rbbi");
      }});
    if (files == null) throw new IOException("Path does not exist: " + srcDir);
    for (int i = 0; i < files.length; i++) {
      File file = files[i];
      File outputFile = new File(destDir, 
          file.getName().replaceAll("rbbi$", "brk"));
      String rules = getRules(file);
      System.err.print("Compiling " + file.getName() + " to "
          + outputFile.getName() + ": ");
      /*
       * if there is a syntax error, compileRules() may succeed. the way to
       * check is to try to instantiate from the string. additionally if the
       * rules are invalid, you can get a useful syntax error.
       */
      try {
        new RuleBasedBreakIterator(rules);
      } catch (IllegalArgumentException e) {
        /*
         * do this intentionally, so you don't get a massive stack trace
         * instead, get a useful syntax error!
         */
        System.err.println(e.getMessage());
        System.exit(1);
      }
      FileOutputStream os = new FileOutputStream(outputFile);
      RuleBasedBreakIterator.compileRules(rules, os);
      os.close();
      System.err.println(outputFile.length() + " bytes.");
    }
  }
  
  public static void main(String args[]) throws Exception {
    if (args.length < 2) {
      System.err.println("Usage: RBBIRuleComputer <sourcedir> ");
      System.exit(1);
    }
    compile(new File(args[0]), new File(args[1]));
    System.exit(0);
  }
}