Lucene example source code file (GenerateJFlexSupplementaryMacros.java)

This example Lucene source code file (GenerateJFlexSupplementaryMacros.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

apache, conditions, extendnumletsupp, hashmap, license, license, nl, nl, string, string, text, unicodeset, unicodeset, unicodesetiterator, util, wordbreak=extendnumlet

The Lucene GenerateJFlexSupplementaryMacros.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.text.DateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Locale;
import java.util.TimeZone;

import com.ibm.icu.text.UnicodeSet;
import com.ibm.icu.text.UnicodeSetIterator;
import com.ibm.icu.util.VersionInfo;

/** creates a macro to augment jflex's unicode wordbreak support for > BMP */
public class GenerateJFlexSupplementaryMacros {
  private static final UnicodeSet BMP = new UnicodeSet("[\u0000-\uFFFF]");
  private static final String NL = System.getProperty("line.separator");
  private static final DateFormat DATE_FORMAT = DateFormat.getDateTimeInstance
    (DateFormat.FULL, DateFormat.FULL, Locale.US);
  static {
    DATE_FORMAT.setTimeZone(TimeZone.getTimeZone("UTC"));
  }
  
  private static final String APACHE_LICENSE 
    = "/*" + NL
      + " * Copyright 2010 The Apache Software Foundation." + NL
      + " *" + NL
      + " * Licensed under the Apache License, Version 2.0 (the \"License\");" + NL
      + " * you may not use this file except in compliance with the License." + NL
      + " * You may obtain a copy of the License at" + NL
      + " *" + NL
      + " *      http://www.apache.org/licenses/LICENSE-2.0" + NL
      + " *" + NL
      + " * Unless required by applicable law or agreed to in writing, software" + NL
      + " * distributed under the License is distributed on an \"AS IS\" BASIS," + NL
      + " * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied." + NL
      + " * See the License for the specific language governing permissions and" + NL
      + " * limitations under the License." + NL
      + " */" + NL + NL;
    
  
  public static void main(String args[]) throws Exception {
    outputHeader();
    outputMacro("ALetterSupp",         "[:WordBreak=ALetter:]");
    outputMacro("FormatSupp",          "[:WordBreak=Format:]");
    outputMacro("ExtendSupp",          "[:WordBreak=Extend:]");
    outputMacro("NumericSupp",         "[:WordBreak=Numeric:]");
    outputMacro("KatakanaSupp",        "[:WordBreak=Katakana:]");
    outputMacro("MidLetterSupp",       "[:WordBreak=MidLetter:]");
    outputMacro("MidNumSupp",          "[:WordBreak=MidNum:]");
    outputMacro("MidNumLetSupp",       "[:WordBreak=MidNumLet:]");
    outputMacro("ExtendNumLetSupp",    "[:WordBreak=ExtendNumLet:]");
    outputMacro("ExtendNumLetSupp",    "[:WordBreak=ExtendNumLet:]");
    outputMacro("ComplexContextSupp",  "[:LineBreak=Complex_Context:]");
    outputMacro("HanSupp",             "[:Script=Han:]");
    outputMacro("HiraganaSupp",        "[:Script=Hiragana:]");
  }
  
  static void outputHeader() {
    System.out.print(APACHE_LICENSE);
    System.out.print("// Generated using ICU4J " + VersionInfo.ICU_VERSION.toString() + " on ");
    System.out.println(DATE_FORMAT.format(new Date()));
    System.out.println("// by " + GenerateJFlexSupplementaryMacros.class.getName());
    System.out.print(NL + NL);
  }
  
  // we have to carefully output the possibilities as compact utf-16
  // range expressions, or jflex will OOM!
  static void outputMacro(String name, String pattern) {
    UnicodeSet set = new UnicodeSet(pattern);
    set.removeAll(BMP);
    System.out.println(name + " = (");
    // if the set is empty, we have to do this or jflex will barf
    if (set.isEmpty()) {
      System.out.println("\t  []");
    }
    
    HashMap<Character,UnicodeSet> utf16ByLead = new HashMap();
    for (UnicodeSetIterator it = new UnicodeSetIterator(set); it.next();) {    
      char utf16[] = Character.toChars(it.codepoint);
      UnicodeSet trails = utf16ByLead.get(utf16[0]);
      if (trails == null) {
        trails = new UnicodeSet();
        utf16ByLead.put(utf16[0], trails);
      }
      trails.add(utf16[1]);
    }
    
    boolean isFirst = true;
    for (Character c : utf16ByLead.keySet()) {
      UnicodeSet trail = utf16ByLead.get(c);
      System.out.print( isFirst ? "\t  " : "\t| ");
      isFirst = false;
      System.out.println("([\\u" + Integer.toHexString(c) + "]" + trail.getRegexEquivalent() + ")");
    }
    System.out.println(")");
  }
}