| /** |
| * 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. |
| */ |
| |
| package org.apache.lucene.analysis; |
| |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| /** |
| * Base utility class for implementing a {@link CharFilter}. |
| * You subclass this, and then record mappings by calling |
| * {@link #addOffCorrectMap}, and then invoke the correct |
| * method to correct an offset. |
| * |
| * <p><b>NOTE</b>: This class is not particularly efficient. |
| * For example, a new class instance is created for every |
| * call to {@link #addOffCorrectMap}, which is then appended |
| * to a private list. |
| */ |
| public abstract class BaseCharFilter extends CharFilter { |
| |
| private List<OffCorrectMap> pcmList; |
| |
| public BaseCharFilter(CharStream in) { |
| super(in); |
| } |
| |
| /** Retrieve the corrected offset. Note that this method |
| * is slow, if you correct positions far before the most |
| * recently added position, as it's a simple linear |
| * search backwards through all offset corrections added |
| * by {@link #addOffCorrectMap}. */ |
| @Override |
| protected int correct(int currentOff) { |
| if (pcmList == null || pcmList.isEmpty()) { |
| return currentOff; |
| } |
| for (int i = pcmList.size() - 1; i >= 0; i--) { |
| if (currentOff >= pcmList.get(i).off) { |
| return currentOff + pcmList.get(i).cumulativeDiff; |
| } |
| } |
| return currentOff; |
| } |
| |
| protected int getLastCumulativeDiff() { |
| return pcmList == null || pcmList.isEmpty() ? |
| 0 : pcmList.get(pcmList.size() - 1).cumulativeDiff; |
| } |
| |
| protected void addOffCorrectMap(int off, int cumulativeDiff) { |
| if (pcmList == null) { |
| pcmList = new ArrayList<OffCorrectMap>(); |
| } |
| pcmList.add(new OffCorrectMap(off, cumulativeDiff)); |
| } |
| |
| static class OffCorrectMap { |
| |
| int off; |
| int cumulativeDiff; |
| |
| OffCorrectMap(int off, int cumulativeDiff) { |
| this.off = off; |
| this.cumulativeDiff = cumulativeDiff; |
| } |
| |
| @Override |
| public String toString() { |
| StringBuilder sb = new StringBuilder(); |
| sb.append('('); |
| sb.append(off); |
| sb.append(','); |
| sb.append(cumulativeDiff); |
| sb.append(')'); |
| return sb.toString(); |
| } |
| } |
| } |