| /* |
| * 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.geronimo.javamail.store.nntp.newsrc; |
| |
| import java.io.IOException; |
| import java.io.Writer; |
| import java.util.ArrayList; |
| import java.util.StringTokenizer; |
| |
| /** |
| * Manage a list of ranges values from a newsrc file. |
| */ |
| public class RangeList { |
| boolean dirty = false; |
| |
| ArrayList ranges = new ArrayList(); |
| |
| /** |
| * Create a RangeList instance from a newsrc range line. Values are saved as |
| * a comma separated set of range values. A range value is either a single |
| * number or a hypenated pair of numbers. |
| * |
| * @param line |
| * The newsrc range line. |
| */ |
| public RangeList(String line) { |
| |
| // we might be creating an first time list, so nothing to parse. |
| if (line != null) { |
| // ranges are comma delimited tokens |
| StringTokenizer tokenizer = new StringTokenizer(line, ","); |
| |
| while (tokenizer.hasMoreTokens()) { |
| String rangeString = (String) tokenizer.nextToken(); |
| rangeString = rangeString.trim(); |
| if (rangeString.length() != 0) { |
| Range range = Range.parse(rangeString); |
| if (range != null) { |
| insert(range); |
| } |
| } |
| } |
| } |
| // make sure we start out in a clean state. Any changes from this point |
| // will flip on the dirty flat. |
| dirty = false; |
| } |
| |
| /** |
| * Insert a range item into our list. If possible, the inserted range will |
| * be merged with existing ranges. |
| * |
| * @param newRange |
| * The new range item. |
| */ |
| public void insert(Range newRange) { |
| // first find the insertion point |
| for (int i = 0; i < ranges.size(); i++) { |
| Range range = (Range) ranges.get(i); |
| // does an existing range fully contain the new range, we don't need |
| // to insert anything. |
| if (range.contains(newRange)) { |
| return; |
| } |
| |
| // does the current one abutt or overlap with the inserted range? |
| if (range.abutts(newRange) || range.overlaps(newRange)) { |
| // rats, we have an overlap...and it is possible that we could |
| // overlap with |
| // the next range after this one too. Therefore, we merge these |
| // two ranges together, |
| // remove the place where we're at, and then recursively insert |
| // the larger range into |
| // the list. |
| dirty = true; |
| newRange.merge(range); |
| ranges.remove(i); |
| insert(newRange); |
| return; |
| } |
| |
| // ok, we don't touch the current one at all. If it is completely |
| // above |
| // range we're adding, we can just poke this into the list here. |
| if (newRange.lessThan(range)) { |
| dirty = true; |
| ranges.add(i, newRange); |
| return; |
| } |
| } |
| dirty = true; |
| // this is easy (and fairly common)...we just tack this on to the end. |
| ranges.add(newRange); |
| } |
| |
| /** |
| * Test if a given article point falls within one of the contained Ranges. |
| * |
| * @param article |
| * The test point. |
| * |
| * @return true if this falls within one of our current mark Ranges, false |
| * otherwise. |
| */ |
| public boolean isMarked(int article) { |
| for (int i = 0; i < ranges.size(); i++) { |
| Range range = (Range) ranges.get(i); |
| if (range.contains(article)) { |
| return true; |
| } |
| // we've passed the point where a match is possible. |
| if (range.greaterThan(article)) { |
| return false; |
| } |
| } |
| return false; |
| } |
| |
| /** |
| * Mark a target article as having been seen. |
| * |
| * @param article |
| * The target article number. |
| */ |
| public void setMarked(int article) { |
| // go through the insertion logic. |
| insert(new Range(article, article)); |
| } |
| |
| /** |
| * Clear the seen mark for a target article. |
| * |
| * @param article |
| * The target article number. |
| */ |
| public void setUnmarked(int article) { |
| for (int i = 0; i < ranges.size(); i++) { |
| Range range = (Range) ranges.get(i); |
| // does this fall within an existing range? We don't need to do |
| // anything here. |
| if (range.contains(article)) { |
| // ok, we've found where to insert, now to figure out how to |
| // insert |
| // article is at the beginning of the range. We can just |
| // increment the lower |
| // bound, or if this is a single element range, we can remove it |
| // entirely. |
| if (range.getStart() == article) { |
| if (range.getEnd() == article) { |
| // piece of cake! |
| ranges.remove(i); |
| } else { |
| // still pretty easy. |
| range.setStart(article + 1); |
| } |
| } else if (range.getEnd() == article) { |
| // pretty easy also |
| range.setEnd(article - 1); |
| } else { |
| // split this into two ranges and insert the trailing piece |
| // after this. |
| Range section = range.split(article); |
| ranges.add(i + 1, section); |
| } |
| dirty = true; |
| return; |
| } |
| // did we find a point where any articles are greater? |
| if (range.greaterThan(article)) { |
| // nothing to do |
| return; |
| } |
| } |
| // didn't find it at all. That was easy! |
| } |
| |
| /** |
| * Save this List of Ranges out to a .newsrc file. This creates a |
| * comma-separated list of range values from each of the Ranges. |
| * |
| * @param out |
| * The target output stream. |
| * |
| * @exception IOException |
| */ |
| public void save(Writer out) throws IOException { |
| // we have an empty list |
| if (ranges.size() == 0) { |
| return; |
| } |
| |
| Range range = (Range) ranges.get(0); |
| range.save(out); |
| |
| for (int i = 1; i < ranges.size(); i++) { |
| out.write(","); |
| range = (Range) ranges.get(i); |
| range.save(out); |
| } |
| } |
| |
| /** |
| * Return the state of the dirty flag. |
| * |
| * @return True if the range list information has changed, false otherwise. |
| */ |
| public boolean isDirty() { |
| return dirty; |
| } |
| } |