Java tutorial
/* * 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.commons.net.nntp; import java.util.ArrayList; /** * This is a class that contains the basic state needed for message retrieval and threading. * With thanks to Jamie Zawinski <jwz@jwz.org> * @author rwinston <rwinston@apache.org> */ public class Article implements Threadable { private long articleNumber; private String subject; private String date; private String articleId; private String simplifiedSubject; private String from; private ArrayList<String> references; private boolean isReply = false; public Article kid, next; public Article() { articleNumber = -1; // isDummy } /** * Adds a message-id to the list of messages that this message references (i.e. replies to) * @param msgId */ public void addReference(String msgId) { if (msgId == null || msgId.length() == 0) { return; } if (references == null) { references = new ArrayList<String>(); } isReply = true; for (String s : msgId.split(" ")) { references.add(s); } } /** * Returns the MessageId references as an array of Strings * @return an array of message-ids */ public String[] getReferences() { if (references == null) { return new String[0]; } return references.toArray(new String[references.size()]); } /** * Attempts to parse the subject line for some typical reply signatures, and strip them out * */ private void simplifySubject() { int start = 0; String subject = getSubject(); int len = subject.length(); boolean done = false; while (!done) { done = true; // skip whitespace // "Re: " breaks this while (start < len && subject.charAt(start) == ' ') { start++; } if (start < (len - 2) && (subject.charAt(start) == 'r' || subject.charAt(start) == 'R') && (subject.charAt(start + 1) == 'e' || subject.charAt(start + 1) == 'E')) { if (subject.charAt(start + 2) == ':') { start += 3; // Skip "Re:" done = false; } else if (start < (len - 2) && (subject.charAt(start + 2) == '[' || subject.charAt(start + 2) == '(')) { int i = start + 3; while (i < len && subject.charAt(i) >= '0' && subject.charAt(i) <= '9') { i++; } if (i < (len - 1) && (subject.charAt(i) == ']' || subject.charAt(i) == ')') && subject.charAt(i + 1) == ':') { start = i + 2; done = false; } } } if ("(no subject)".equals(simplifiedSubject)) { simplifiedSubject = ""; } int end = len; while (end > start && subject.charAt(end - 1) < ' ') { end--; } if (start == 0 && end == len) { simplifiedSubject = subject; } else { simplifiedSubject = subject.substring(start, end); } } } /** * Recursive method that traverses a pre-threaded graph (or tree) * of connected Article objects and prints them out. * @param article the root of the article 'tree' * @param depth the current tree depth */ public static void printThread(Article article, int depth) { for (int i = 0; i < depth; ++i) { System.out.print("==>"); } System.out.println(article.getSubject() + "\t" + article.getFrom() + "\t" + article.getArticleId()); if (article.kid != null) { printThread(article.kid, depth + 1); } if (article.next != null) { printThread(article.next, depth); } } public String getArticleId() { return articleId; } public long getArticleNumberLong() { return articleNumber; } public String getDate() { return date; } public String getFrom() { return from; } public String getSubject() { return subject; } public void setArticleId(String string) { articleId = string; } public void setArticleNumber(long l) { articleNumber = l; } public void setDate(String string) { date = string; } public void setFrom(String string) { from = string; } public void setSubject(String string) { subject = string; } // @Override public boolean isDummy() { return (articleNumber == -1); } // @Override public String messageThreadId() { return articleId; } // @Override public String[] messageThreadReferences() { return getReferences(); } // @Override public String simplifiedSubject() { if (simplifiedSubject == null) { simplifySubject(); } return simplifiedSubject; } // @Override public boolean subjectIsReply() { return isReply; } // @Override public void setChild(Threadable child) { this.kid = (Article) child; flushSubjectCache(); } private void flushSubjectCache() { simplifiedSubject = null; } // @Override public void setNext(Threadable next) { this.next = (Article) next; flushSubjectCache(); } // @Override public Threadable makeDummy() { return new Article(); } @Override public String toString() { // Useful for Eclipse debugging return articleNumber + " " + articleId + " " + subject; } // DEPRECATED METHODS - for API compatibility only - DO NOT USE @Deprecated public int getArticleNumber() { return (int) articleNumber; } @Deprecated public void setArticleNumber(int a) { articleNumber = a; } @Deprecated public void addHeaderField(String name, String val) { } }