/*
 * 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
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package org.apache.lucene.analysis.path;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
import org.apache.lucene.util.AttributeFactory;

Tokenizer for domain-like hierarchies.

Take something like:

www.site.co.uk
and make:
www.site.co.uk
site.co.uk
co.uk
uk
/** * Tokenizer for domain-like hierarchies. * <p> * Take something like: * * <pre> * www.site.co.uk * </pre> * * and make: * * <pre> * www.site.co.uk * site.co.uk * co.uk * uk * </pre> * */
public class ReversePathHierarchyTokenizer extends Tokenizer { public ReversePathHierarchyTokenizer() { this(DEFAULT_BUFFER_SIZE, DEFAULT_DELIMITER, DEFAULT_DELIMITER, DEFAULT_SKIP); } public ReversePathHierarchyTokenizer(int skip) { this(DEFAULT_BUFFER_SIZE, DEFAULT_DELIMITER, DEFAULT_DELIMITER, skip); } public ReversePathHierarchyTokenizer(int bufferSize, char delimiter) { this(bufferSize, delimiter, delimiter, DEFAULT_SKIP); } public ReversePathHierarchyTokenizer(char delimiter, char replacement) { this(DEFAULT_BUFFER_SIZE, delimiter, replacement, DEFAULT_SKIP); } public ReversePathHierarchyTokenizer(int bufferSize, char delimiter, char replacement) { this(bufferSize, delimiter, replacement, DEFAULT_SKIP); } public ReversePathHierarchyTokenizer(char delimiter, int skip) { this( DEFAULT_BUFFER_SIZE, delimiter, delimiter, skip); } public ReversePathHierarchyTokenizer(char delimiter, char replacement, int skip) { this(DEFAULT_BUFFER_SIZE, delimiter, replacement, skip); } public ReversePathHierarchyTokenizer (AttributeFactory factory, char delimiter, char replacement, int skip) { this(factory, DEFAULT_BUFFER_SIZE, delimiter, replacement, skip); } public ReversePathHierarchyTokenizer( int bufferSize, char delimiter, char replacement, int skip) { this(DEFAULT_TOKEN_ATTRIBUTE_FACTORY, bufferSize, delimiter, replacement, skip); } public ReversePathHierarchyTokenizer (AttributeFactory factory, int bufferSize, char delimiter, char replacement, int skip) { super(factory); if (bufferSize < 0) { throw new IllegalArgumentException("bufferSize cannot be negative"); } if (skip < 0) { throw new IllegalArgumentException("skip cannot be negative"); } termAtt.resizeBuffer(bufferSize); this.delimiter = delimiter; this.replacement = replacement; this.skip = skip; resultToken = new StringBuilder(bufferSize); resultTokenBuffer = new char[bufferSize]; delimiterPositions = new ArrayList<>(bufferSize/10); } private static final int DEFAULT_BUFFER_SIZE = 1024; public static final char DEFAULT_DELIMITER = '/'; public static final int DEFAULT_SKIP = 0; private final char delimiter; private final char replacement; private final int skip; private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class); private final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class); private final PositionIncrementAttribute posAtt = addAttribute(PositionIncrementAttribute.class); private int endPosition = 0; private int finalOffset = 0; private int skipped = 0; private StringBuilder resultToken; private List<Integer> delimiterPositions; private int delimitersCount = -1; private char[] resultTokenBuffer; @Override public final boolean incrementToken() throws IOException { clearAttributes(); if(delimitersCount == -1){ int length = 0; delimiterPositions.add(0); while (true) { int c = input.read(); if( c < 0 ) { break; } length++; if( c == delimiter ) { delimiterPositions.add(length); resultToken.append(replacement); } else{ resultToken.append((char)c); } } delimitersCount = delimiterPositions.size(); if( delimiterPositions.get(delimitersCount-1) < length ){ delimiterPositions.add(length); delimitersCount++; } if( resultTokenBuffer.length < resultToken.length() ){ resultTokenBuffer = new char[resultToken.length()]; } resultToken.getChars(0, resultToken.length(), resultTokenBuffer, 0); resultToken.setLength(0); int idx = delimitersCount-1 - skip; if (idx >= 0) { // otherwise it's ok, because we will skip and return false endPosition = delimiterPositions.get(idx); } finalOffset = correctOffset(length); posAtt.setPositionIncrement(1); } else{ posAtt.setPositionIncrement(0); } while( skipped < delimitersCount-skip-1 ){ int start = delimiterPositions.get(skipped); termAtt.copyBuffer(resultTokenBuffer, start, endPosition - start); offsetAtt.setOffset(correctOffset(start), correctOffset(endPosition)); skipped++; return true; } return false; } @Override public final void end() throws IOException { super.end(); // set final offset offsetAtt.setOffset(finalOffset, finalOffset); } @Override public void reset() throws IOException { super.reset(); resultToken.setLength(0); finalOffset = 0; endPosition = 0; skipped = 0; delimitersCount = -1; delimiterPositions.clear(); } }