Java tutorial
/* * Copyright 2001-2005 The Apache Software Foundation * * Licensed 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.eredlab.g4.ccl.net.nntp; import java.io.BufferedReader; import java.io.IOException; import java.io.Reader; import java.io.StringWriter; import java.io.Writer; import java.util.StringTokenizer; import java.util.Vector; import org.eredlab.g4.ccl.net.MalformedServerReplyException; import org.eredlab.g4.ccl.net.io.DotTerminatedMessageReader; import org.eredlab.g4.ccl.net.io.DotTerminatedMessageWriter; import org.eredlab.g4.ccl.net.io.Util; /*** * NNTPClient encapsulates all the functionality necessary to post and * retrieve articles from an NNTP server. As with all classes derived * from {@link org.apache.commons.net.SocketClient}, * you must first connect to the server with * {@link org.apache.commons.net.SocketClient#connect connect } * before doing anything, and finally * {@link org.apache.commons.net.nntp.NNTP#disconnect disconnect() } * after you're completely finished interacting with the server. * Remember that the * {@link org.apache.commons.net.nntp.NNTP#isAllowedToPost isAllowedToPost()} * method is defined in * {@link org.apache.commons.net.nntp.NNTP}. * <p> * You should keep in mind that the NNTP server may choose to prematurely * close a connection if the client has been idle for longer than a * given time period or if the server is being shutdown by the operator or * some other reason. The NNTP class will detect a * premature NNTP server connection closing when it receives a * {@link org.apache.commons.net.nntp.NNTPReply#SERVICE_DISCONTINUED NNTPReply.SERVICE_DISCONTINUED } * response to a command. * When that occurs, the NNTP class method encountering that reply will throw * an {@link org.apache.commons.net.nntp.NNTPConnectionClosedException} * . * <code>NNTPConectionClosedException</code> * is a subclass of <code> IOException </code> and therefore need not be * caught separately, but if you are going to catch it separately, its * catch block must appear before the more general <code> IOException </code> * catch block. When you encounter an * {@link org.apache.commons.net.nntp.NNTPConnectionClosedException} * , you must disconnect the connection with * {@link org.apache.commons.net.nntp.NNTP#disconnect disconnect() } * to properly clean up the * system resources used by NNTP. Before disconnecting, you may check the * last reply code and text with * {@link org.apache.commons.net.nntp.NNTP#getReplyCode getReplyCode } and * {@link org.apache.commons.net.nntp.NNTP#getReplyString getReplyString }. * <p> * Rather than list it separately for each method, we mention here that * every method communicating with the server and throwing an IOException * can also throw a * {@link org.apache.commons.net.MalformedServerReplyException} * , which is a subclass * of IOException. A MalformedServerReplyException will be thrown when * the reply received from the server deviates enough from the protocol * specification that it cannot be interpreted in a useful manner despite * attempts to be as lenient as possible. * <p> * <p> * @author Daniel F. Savarese * @author Rory Winston * @author Ted Wise * @see NNTP * @see NNTPConnectionClosedException * @see org.apache.commons.net.MalformedServerReplyException ***/ public class NNTPClient extends NNTP { private void __parseArticlePointer(String reply, ArticlePointer pointer) throws MalformedServerReplyException { StringTokenizer tokenizer; // Do loop is a kluge to simulate goto do { tokenizer = new StringTokenizer(reply); if (tokenizer.countTokens() < 3) break; // Skip numeric response value tokenizer.nextToken(); // Get article number try { pointer.articleNumber = Integer.parseInt(tokenizer.nextToken()); } catch (NumberFormatException e) { break; } // Get article id pointer.articleId = tokenizer.nextToken(); return; } while (false); throw new MalformedServerReplyException("Could not parse article pointer.\nServer reply: " + reply); } private void __parseGroupReply(String reply, NewsgroupInfo info) throws MalformedServerReplyException { String count, first, last; StringTokenizer tokenizer; // Do loop is a kluge to simulate goto do { tokenizer = new StringTokenizer(reply); if (tokenizer.countTokens() < 5) break; // Skip numeric response value tokenizer.nextToken(); // Get estimated article count count = tokenizer.nextToken(); // Get first article number first = tokenizer.nextToken(); // Get last article number last = tokenizer.nextToken(); // Get newsgroup name info._setNewsgroup(tokenizer.nextToken()); try { info._setArticleCount(Integer.parseInt(count)); info._setFirstArticle(Integer.parseInt(first)); info._setLastArticle(Integer.parseInt(last)); } catch (NumberFormatException e) { break; } info._setPostingPermission(NewsgroupInfo.UNKNOWN_POSTING_PERMISSION); return; } while (false); throw new MalformedServerReplyException("Could not parse newsgroup info.\nServer reply: " + reply); } private NewsgroupInfo __parseNewsgroupListEntry(String entry) { NewsgroupInfo result; StringTokenizer tokenizer; int lastNum, firstNum; String last, first, permission; result = new NewsgroupInfo(); tokenizer = new StringTokenizer(entry); if (tokenizer.countTokens() < 4) return null; result._setNewsgroup(tokenizer.nextToken()); last = tokenizer.nextToken(); first = tokenizer.nextToken(); permission = tokenizer.nextToken(); try { lastNum = Integer.parseInt(last); firstNum = Integer.parseInt(first); result._setFirstArticle(firstNum); result._setLastArticle(lastNum); if ((firstNum == 0) && (lastNum == 0)) result._setArticleCount(0); else result._setArticleCount(lastNum - firstNum + 1); } catch (NumberFormatException e) { return null; } switch (permission.charAt(0)) { case 'y': case 'Y': result._setPostingPermission(NewsgroupInfo.PERMITTED_POSTING_PERMISSION); break; case 'n': case 'N': result._setPostingPermission(NewsgroupInfo.PROHIBITED_POSTING_PERMISSION); break; case 'm': case 'M': result._setPostingPermission(NewsgroupInfo.MODERATED_POSTING_PERMISSION); break; default: result._setPostingPermission(NewsgroupInfo.UNKNOWN_POSTING_PERMISSION); break; } return result; } private NewsgroupInfo[] __readNewsgroupListing() throws IOException { int size; String line; Vector list; BufferedReader reader; NewsgroupInfo tmp, info[]; reader = new BufferedReader(new DotTerminatedMessageReader(_reader_)); // Start of with a big vector because we may be reading a very large // amount of groups. list = new Vector(2048); while ((line = reader.readLine()) != null) { tmp = __parseNewsgroupListEntry(line); if (tmp != null) list.addElement(tmp); else throw new MalformedServerReplyException(line); } if ((size = list.size()) < 1) return new NewsgroupInfo[0]; info = new NewsgroupInfo[size]; list.copyInto(info); return info; } private Reader __retrieve(int command, String articleId, ArticlePointer pointer) throws IOException { Reader reader; if (articleId != null) { if (!NNTPReply.isPositiveCompletion(sendCommand(command, articleId))) return null; } else { if (!NNTPReply.isPositiveCompletion(sendCommand(command))) return null; } if (pointer != null) __parseArticlePointer(getReplyString(), pointer); reader = new DotTerminatedMessageReader(_reader_); return reader; } private Reader __retrieve(int command, int articleNumber, ArticlePointer pointer) throws IOException { Reader reader; if (!NNTPReply.isPositiveCompletion(sendCommand(command, Integer.toString(articleNumber)))) return null; if (pointer != null) __parseArticlePointer(getReplyString(), pointer); reader = new DotTerminatedMessageReader(_reader_); return reader; } /*** * Retrieves an article from the NNTP server. The article is referenced * by its unique article identifier (including the enclosing < and >). * The article number and identifier contained in the server reply * are returned through an ArticlePointer. The <code> articleId </code> * field of the ArticlePointer cannot always be trusted because some * NNTP servers do not correctly follow the RFC 977 reply format. * <p> * A DotTerminatedMessageReader is returned from which the article can * be read. If the article does not exist, null is returned. * <p> * You must not issue any commands to the NNTP server (i.e., call any * other methods) until you finish reading the message from the returned * Reader instance. * The NNTP protocol uses the same stream for issuing commands as it does * for returning results. Therefore the returned Reader actually reads * directly from the NNTP connection. After the end of message has been * reached, new commands can be executed and their replies read. If * you do not follow these requirements, your program will not work * properly. * <p> * @param articleId The unique article identifier of the article to * retrieve. If this parameter is null, the currently selected * article is retrieved. * @param pointer A parameter through which to return the article's * number and unique id. The articleId field cannot always be trusted * because of server deviations from RFC 977 reply formats. You may * set this parameter to null if you do not desire to retrieve the * returned article information. * @return A DotTerminatedMessageReader instance from which the article * be read. null if the article does not exist. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public Reader retrieveArticle(String articleId, ArticlePointer pointer) throws IOException { return __retrieve(NNTPCommand.ARTICLE, articleId, pointer); } /*** Same as <code> retrieveArticle(articleId, null) </code> ***/ public Reader retrieveArticle(String articleId) throws IOException { return retrieveArticle(articleId, null); } /*** Same as <code> retrieveArticle(null) </code> ***/ public Reader retrieveArticle() throws IOException { return retrieveArticle(null); } /*** * Retrieves an article from the currently selected newsgroup. The * article is referenced by its article number. * The article number and identifier contained in the server reply * are returned through an ArticlePointer. The <code> articleId </code> * field of the ArticlePointer cannot always be trusted because some * NNTP servers do not correctly follow the RFC 977 reply format. * <p> * A DotTerminatedMessageReader is returned from which the article can * be read. If the article does not exist, null is returned. * <p> * You must not issue any commands to the NNTP server (i.e., call any * other methods) until you finish reading the message from the returned * Reader instance. * The NNTP protocol uses the same stream for issuing commands as it does * for returning results. Therefore the returned Reader actually reads * directly from the NNTP connection. After the end of message has been * reached, new commands can be executed and their replies read. If * you do not follow these requirements, your program will not work * properly. * <p> * @param articleNumber The number of the the article to * retrieve. * @param pointer A parameter through which to return the article's * number and unique id. The articleId field cannot always be trusted * because of server deviations from RFC 977 reply formats. You may * set this parameter to null if you do not desire to retrieve the * returned article information. * @return A DotTerminatedMessageReader instance from which the article * be read. null if the article does not exist. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public Reader retrieveArticle(int articleNumber, ArticlePointer pointer) throws IOException { return __retrieve(NNTPCommand.ARTICLE, articleNumber, pointer); } /*** Same as <code> retrieveArticle(articleNumber, null) </code> ***/ public Reader retrieveArticle(int articleNumber) throws IOException { return retrieveArticle(articleNumber, null); } /*** * Retrieves an article header from the NNTP server. The article is * referenced * by its unique article identifier (including the enclosing < and >). * The article number and identifier contained in the server reply * are returned through an ArticlePointer. The <code> articleId </code> * field of the ArticlePointer cannot always be trusted because some * NNTP servers do not correctly follow the RFC 977 reply format. * <p> * A DotTerminatedMessageReader is returned from which the article can * be read. If the article does not exist, null is returned. * <p> * You must not issue any commands to the NNTP server (i.e., call any * other methods) until you finish reading the message from the returned * Reader instance. * The NNTP protocol uses the same stream for issuing commands as it does * for returning results. Therefore the returned Reader actually reads * directly from the NNTP connection. After the end of message has been * reached, new commands can be executed and their replies read. If * you do not follow these requirements, your program will not work * properly. * <p> * @param articleId The unique article identifier of the article whose * header is being retrieved. If this parameter is null, the * header of the currently selected article is retrieved. * @param pointer A parameter through which to return the article's * number and unique id. The articleId field cannot always be trusted * because of server deviations from RFC 977 reply formats. You may * set this parameter to null if you do not desire to retrieve the * returned article information. * @return A DotTerminatedMessageReader instance from which the article * header can be read. null if the article does not exist. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public Reader retrieveArticleHeader(String articleId, ArticlePointer pointer) throws IOException { return __retrieve(NNTPCommand.HEAD, articleId, pointer); } /*** Same as <code> retrieveArticleHeader(articleId, null) </code> ***/ public Reader retrieveArticleHeader(String articleId) throws IOException { return retrieveArticleHeader(articleId, null); } /*** Same as <code> retrieveArticleHeader(null) </code> ***/ public Reader retrieveArticleHeader() throws IOException { return retrieveArticleHeader(null); } /*** * Retrieves an article header from the currently selected newsgroup. The * article is referenced by its article number. * The article number and identifier contained in the server reply * are returned through an ArticlePointer. The <code> articleId </code> * field of the ArticlePointer cannot always be trusted because some * NNTP servers do not correctly follow the RFC 977 reply format. * <p> * A DotTerminatedMessageReader is returned from which the article can * be read. If the article does not exist, null is returned. * <p> * You must not issue any commands to the NNTP server (i.e., call any * other methods) until you finish reading the message from the returned * Reader instance. * The NNTP protocol uses the same stream for issuing commands as it does * for returning results. Therefore the returned Reader actually reads * directly from the NNTP connection. After the end of message has been * reached, new commands can be executed and their replies read. If * you do not follow these requirements, your program will not work * properly. * <p> * @param articleNumber The number of the the article whose header is * being retrieved. * @param pointer A parameter through which to return the article's * number and unique id. The articleId field cannot always be trusted * because of server deviations from RFC 977 reply formats. You may * set this parameter to null if you do not desire to retrieve the * returned article information. * @return A DotTerminatedMessageReader instance from which the article * header can be read. null if the article does not exist. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public Reader retrieveArticleHeader(int articleNumber, ArticlePointer pointer) throws IOException { return __retrieve(NNTPCommand.HEAD, articleNumber, pointer); } /*** Same as <code> retrieveArticleHeader(articleNumber, null) </code> ***/ public Reader retrieveArticleHeader(int articleNumber) throws IOException { return retrieveArticleHeader(articleNumber, null); } /*** * Retrieves an article body from the NNTP server. The article is * referenced * by its unique article identifier (including the enclosing < and >). * The article number and identifier contained in the server reply * are returned through an ArticlePointer. The <code> articleId </code> * field of the ArticlePointer cannot always be trusted because some * NNTP servers do not correctly follow the RFC 977 reply format. * <p> * A DotTerminatedMessageReader is returned from which the article can * be read. If the article does not exist, null is returned. * <p> * You must not issue any commands to the NNTP server (i.e., call any * other methods) until you finish reading the message from the returned * Reader instance. * The NNTP protocol uses the same stream for issuing commands as it does * for returning results. Therefore the returned Reader actually reads * directly from the NNTP connection. After the end of message has been * reached, new commands can be executed and their replies read. If * you do not follow these requirements, your program will not work * properly. * <p> * @param articleId The unique article identifier of the article whose * body is being retrieved. If this parameter is null, the * body of the currently selected article is retrieved. * @param pointer A parameter through which to return the article's * number and unique id. The articleId field cannot always be trusted * because of server deviations from RFC 977 reply formats. You may * set this parameter to null if you do not desire to retrieve the * returned article information. * @return A DotTerminatedMessageReader instance from which the article * body can be read. null if the article does not exist. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public Reader retrieveArticleBody(String articleId, ArticlePointer pointer) throws IOException { return __retrieve(NNTPCommand.BODY, articleId, pointer); } /*** Same as <code> retrieveArticleBody(articleId, null) </code> ***/ public Reader retrieveArticleBody(String articleId) throws IOException { return retrieveArticleBody(articleId, null); } /*** Same as <code> retrieveArticleBody(null) </code> ***/ public Reader retrieveArticleBody() throws IOException { return retrieveArticleBody(null); } /*** * Retrieves an article body from the currently selected newsgroup. The * article is referenced by its article number. * The article number and identifier contained in the server reply * are returned through an ArticlePointer. The <code> articleId </code> * field of the ArticlePointer cannot always be trusted because some * NNTP servers do not correctly follow the RFC 977 reply format. * <p> * A DotTerminatedMessageReader is returned from which the article can * be read. If the article does not exist, null is returned. * <p> * You must not issue any commands to the NNTP server (i.e., call any * other methods) until you finish reading the message from the returned * Reader instance. * The NNTP protocol uses the same stream for issuing commands as it does * for returning results. Therefore the returned Reader actually reads * directly from the NNTP connection. After the end of message has been * reached, new commands can be executed and their replies read. If * you do not follow these requirements, your program will not work * properly. * <p> * @param articleNumber The number of the the article whose body is * being retrieved. * @param pointer A parameter through which to return the article's * number and unique id. The articleId field cannot always be trusted * because of server deviations from RFC 977 reply formats. You may * set this parameter to null if you do not desire to retrieve the * returned article information. * @return A DotTerminatedMessageReader instance from which the article * body can be read. null if the article does not exist. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public Reader retrieveArticleBody(int articleNumber, ArticlePointer pointer) throws IOException { return __retrieve(NNTPCommand.BODY, articleNumber, pointer); } /*** Same as <code> retrieveArticleBody(articleNumber, null) </code> ***/ public Reader retrieveArticleBody(int articleNumber) throws IOException { return retrieveArticleBody(articleNumber, null); } /*** * Select the specified newsgroup to be the target of for future article * retrieval and posting operations. Also return the newsgroup * information contained in the server reply through the info parameter. * <p> * @param newsgroup The newsgroup to select. * @param info A parameter through which the newsgroup information of * the selected newsgroup contained in the server reply is returned. * Set this to null if you do not desire this information. * @return True if the newsgroup exists and was selected, false otherwise. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public boolean selectNewsgroup(String newsgroup, NewsgroupInfo info) throws IOException { if (!NNTPReply.isPositiveCompletion(group(newsgroup))) return false; if (info != null) __parseGroupReply(getReplyString(), info); return true; } /*** Same as <code> selectNewsgroup(newsgroup, null) </code> ***/ public boolean selectNewsgroup(String newsgroup) throws IOException { return selectNewsgroup(newsgroup, null); } /*** * List the command help from the server. * <p> * @return The sever help information. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public String listHelp() throws IOException { StringWriter help; Reader reader; if (!NNTPReply.isInformational(help())) return null; help = new StringWriter(); reader = new DotTerminatedMessageReader(_reader_); Util.copyReader(reader, help); reader.close(); help.close(); return help.toString(); } /*** * Select an article by its unique identifier (including enclosing * < and >) and return its article number and id through the * pointer parameter. This is achieved through the STAT command. * According to RFC 977, this will NOT set the current article pointer * on the server. To do that, you must reference the article by its * number. * <p> * @param articleId The unique article identifier of the article that * is being selectedd. If this parameter is null, the * body of the current article is selected * @param pointer A parameter through which to return the article's * number and unique id. The articleId field cannot always be trusted * because of server deviations from RFC 977 reply formats. You may * set this parameter to null if you do not desire to retrieve the * returned article information. * @return True if successful, false if not. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public boolean selectArticle(String articleId, ArticlePointer pointer) throws IOException { if (articleId != null) { if (!NNTPReply.isPositiveCompletion(stat(articleId))) return false; } else { if (!NNTPReply.isPositiveCompletion(stat())) return false; } if (pointer != null) __parseArticlePointer(getReplyString(), pointer); return true; } /**** Same as <code> selectArticle(articleId, null) </code> ***/ public boolean selectArticle(String articleId) throws IOException { return selectArticle(articleId, null); } /**** * Same as <code> selectArticle(null, articleId) </code>. Useful * for retrieving the current article number. ***/ public boolean selectArticle(ArticlePointer pointer) throws IOException { return selectArticle(null, pointer); } /*** * Select an article in the currently selected newsgroup by its number. * and return its article number and id through the * pointer parameter. This is achieved through the STAT command. * According to RFC 977, this WILL set the current article pointer * on the server. Use this command to select an article before retrieving * it, or to obtain an article's unique identifier given its number. * <p> * @param articleNumber The number of the article to select from the * currently selected newsgroup. * @param pointer A parameter through which to return the article's * number and unique id. Although the articleId field cannot always * be trusted because of server deviations from RFC 977 reply formats, * we haven't found a server that misformats this information in response * to this particular command. You may set this parameter to null if * you do not desire to retrieve the returned article information. * @return True if successful, false if not. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public boolean selectArticle(int articleNumber, ArticlePointer pointer) throws IOException { if (!NNTPReply.isPositiveCompletion(stat(articleNumber))) return false; if (pointer != null) __parseArticlePointer(getReplyString(), pointer); return true; } /*** Same as <code> selectArticle(articleNumber, null) </code> ***/ public boolean selectArticle(int articleNumber) throws IOException { return selectArticle(articleNumber, null); } /*** * Select the article preceeding the currently selected article in the * currently selected newsgroup and return its number and unique id * through the pointer parameter. Because of deviating server * implementations, the articleId information cannot be trusted. To * obtain the article identifier, issue a * <code> selectArticle(pointer.articleNumber, pointer) </code> immediately * afterward. * <p> * @param pointer A parameter through which to return the article's * number and unique id. The articleId field cannot always be trusted * because of server deviations from RFC 977 reply formats. You may * set this parameter to null if you do not desire to retrieve the * returned article information. * @return True if successful, false if not (e.g., there is no previous * article). * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public boolean selectPreviousArticle(ArticlePointer pointer) throws IOException { if (!NNTPReply.isPositiveCompletion(last())) return false; if (pointer != null) __parseArticlePointer(getReplyString(), pointer); return true; } /*** Same as <code> selectPreviousArticle(null) </code> ***/ public boolean selectPreviousArticle() throws IOException { return selectPreviousArticle(null); } /*** * Select the article following the currently selected article in the * currently selected newsgroup and return its number and unique id * through the pointer parameter. Because of deviating server * implementations, the articleId information cannot be trusted. To * obtain the article identifier, issue a * <code> selectArticle(pointer.articleNumber, pointer) </code> immediately * afterward. * <p> * @param pointer A parameter through which to return the article's * number and unique id. The articleId field cannot always be trusted * because of server deviations from RFC 977 reply formats. You may * set this parameter to null if you do not desire to retrieve the * returned article information. * @return True if successful, false if not (e.g., there is no following * article). * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public boolean selectNextArticle(ArticlePointer pointer) throws IOException { if (!NNTPReply.isPositiveCompletion(next())) return false; if (pointer != null) __parseArticlePointer(getReplyString(), pointer); return true; } /*** Same as <code> selectNextArticle(null) </code> ***/ public boolean selectNextArticle() throws IOException { return selectNextArticle(null); } /*** * List all newsgroups served by the NNTP server. If no newsgroups * are served, a zero length array will be returned. If the command * fails, null will be returned. * <p> * @return An array of NewsgroupInfo instances containing the information * for each newsgroup served by the NNTP server. If no newsgroups * are served, a zero length array will be returned. If the command * fails, null will be returned. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public NewsgroupInfo[] listNewsgroups() throws IOException { if (!NNTPReply.isPositiveCompletion(list())) return null; return __readNewsgroupListing(); } /** * An overloaded listNewsgroups() command that allows us to * specify with a pattern what groups we want to list. Wraps the * LIST ACTIVE command. * <p> * @param wildmat a pseudo-regex pattern (cf. RFC 2980) * @return An array of NewsgroupInfo instances containing the information * for each newsgroup served by the NNTP server corresponding to the * supplied pattern. If no such newsgroups are served, a zero length * array will be returned. If the command fails, null will be returned. * @throws IOException */ public NewsgroupInfo[] listNewsgroups(String wildmat) throws IOException { if (!NNTPReply.isPositiveCompletion(listActive(wildmat))) return null; return __readNewsgroupListing(); } /*** * List all new newsgroups added to the NNTP server since a particular * date subject to the conditions of the specified query. If no new * newsgroups were added, a zero length array will be returned. If the * command fails, null will be returned. * <p> * @param query The query restricting how to search for new newsgroups. * @return An array of NewsgroupInfo instances containing the information * for each new newsgroup added to the NNTP server. If no newsgroups * were added, a zero length array will be returned. If the command * fails, null will be returned. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public NewsgroupInfo[] listNewNewsgroups(NewGroupsOrNewsQuery query) throws IOException { if (!NNTPReply.isPositiveCompletion( newgroups(query.getDate(), query.getTime(), query.isGMT(), query.getDistributions()))) return null; return __readNewsgroupListing(); } /*** * List all new articles added to the NNTP server since a particular * date subject to the conditions of the specified query. If no new * new news is found, a zero length array will be returned. If the * command fails, null will be returned. You must add at least one * newsgroup to the query, else the command will fail. Each String * in the returned array is a unique message identifier including the * enclosing < and >. * <p> * @param query The query restricting how to search for new news. You * must add at least one newsgroup to the query. * @return An array of String instances containing the unique message * identifiers for each new article added to the NNTP server. If no * new news is found, a zero length array will be returned. If the * command fails, null will be returned. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public String[] listNewNews(NewGroupsOrNewsQuery query) throws IOException { int size; String line; Vector list; String[] result; BufferedReader reader; if (!NNTPReply.isPositiveCompletion(newnews(query.getNewsgroups(), query.getDate(), query.getTime(), query.isGMT(), query.getDistributions()))) return null; list = new Vector(); reader = new BufferedReader(new DotTerminatedMessageReader(_reader_)); while ((line = reader.readLine()) != null) list.addElement(line); size = list.size(); if (size < 1) return new String[0]; result = new String[size]; list.copyInto(result); return result; } /*** * There are a few NNTPClient methods that do not complete the * entire sequence of NNTP commands to complete a transaction. These * commands require some action by the programmer after the reception * of a positive preliminary command. After the programmer's code * completes its actions, it must call this method to receive * the completion reply from the server and verify the success of the * entire transaction. * <p> * For example * <pre> * writer = client.postArticle(); * if(writer == null) // failure * return false; * header = new SimpleNNTPHeader("foobar@foo.com", "Just testing"); * header.addNewsgroup("alt.test"); * writer.write(header.toString()); * writer.write("This is just a test"); * writer.close(); * if(!client.completePendingCommand()) // failure * return false; * </pre> * <p> * @return True if successfully completed, false if not. * @exception NNTPConnectionClosedException * If the NNTP server prematurely closes the connection as a result * of the client being idle or some other reason causing the server * to send NNTP reply code 400. This exception may be caught either * as an IOException or independently as itself. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public boolean completePendingCommand() throws IOException { return NNTPReply.isPositiveCompletion(getReply()); } /*** * Post an article to the NNTP server. This method returns a * DotTerminatedMessageWriter instance to which the article can be * written. Null is returned if the posting attempt fails. You * should check {@link NNTP#isAllowedToPost isAllowedToPost() } * before trying to post. However, a posting * attempt can fail due to malformed headers. * <p> * You must not issue any commands to the NNTP server (i.e., call any * (other methods) until you finish writing to the returned Writer * instance and close it. The NNTP protocol uses the same stream for * issuing commands as it does for returning results. Therefore the * returned Writer actually writes directly to the NNTP connection. * After you close the writer, you can execute new commands. If you * do not follow these requirements your program will not work properly. * <p> * Different NNTP servers will require different header formats, but * you can use the provided * {@link org.apache.commons.net.nntp.SimpleNNTPHeader} * class to construct the bare minimum acceptable header for most * news readers. To construct more complicated headers you should * refer to RFC 822. When the Java Mail API is finalized, you will be * able to use it to compose fully compliant Internet text messages. * The DotTerminatedMessageWriter takes care of doubling line-leading * dots and ending the message with a single dot upon closing, so all * you have to worry about is writing the header and the message. * <p> * Upon closing the returned Writer, you need to call * {@link #completePendingCommand completePendingCommand() } * to finalize the posting and verify its success or failure from * the server reply. * <p> * @return A DotTerminatedMessageWriter to which the article (including * header) can be written. Returns null if the command fails. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public Writer postArticle() throws IOException { if (!NNTPReply.isPositiveIntermediate(post())) return null; return new DotTerminatedMessageWriter(_writer_); } public Writer forwardArticle(String articleId) throws IOException { if (!NNTPReply.isPositiveIntermediate(ihave(articleId))) return null; return new DotTerminatedMessageWriter(_writer_); } /*** * Logs out of the news server gracefully by sending the QUIT command. * However, you must still disconnect from the server before you can open * a new connection. * <p> * @return True if successfully completed, false if not. * @exception IOException If an I/O error occurs while either sending a * command to the server or receiving a reply from the server. ***/ public boolean logout() throws IOException { return NNTPReply.isPositiveCompletion(quit()); } /** * Log into a news server by sending the AUTHINFO USER/AUTHINFO * PASS command sequence. This is usually sent in response to a * 480 reply code from the NNTP server. * <p> * @param username a valid username * @param password the corresponding password * @return True for successful login, false for a failure * @throws IOException */ public boolean authenticate(String username, String password) throws IOException { int replyCode = authinfoUser(username); if (replyCode == NNTPReply.MORE_AUTH_INFO_REQUIRED) { replyCode = authinfoPass(password); if (replyCode == NNTPReply.AUTHENTICATION_ACCEPTED) { _isAllowedToPost = true; return true; } } return false; } /*** * Private implementation of XOVER functionality. * * See {@link NNTP#xover} * for legal agument formats. Alternatively, read RFC 2980 :-) * <p> * @param articleRange * @return Returns a DotTerminatedMessageReader if successful, null * otherwise * @exception IOException */ private Reader __retrieveArticleInfo(String articleRange) throws IOException { if (!NNTPReply.isPositiveCompletion(xover(articleRange))) return null; return new DotTerminatedMessageReader(_reader_); } /** * Return article headers for a specified post. * <p> * @param articleNumber the article to retrieve headers for * @return a DotTerminatedReader if successful, null otherwise * @throws IOException */ public Reader retrieveArticleInfo(int articleNumber) throws IOException { return __retrieveArticleInfo(Integer.toString(articleNumber)); } /** * Return article headers for all articles between lowArticleNumber * and highArticleNumber, inclusively. * <p> * @param lowArticleNumber * @param highArticleNumber * @return a DotTerminatedReader if successful, null otherwise * @throws IOException */ public Reader retrieveArticleInfo(int lowArticleNumber, int highArticleNumber) throws IOException { return __retrieveArticleInfo(new String(lowArticleNumber + "-" + highArticleNumber)); } /*** * Private implementation of XHDR functionality. * * See {@link NNTP#xhdr} * for legal agument formats. Alternatively, read RFC 1036. * <p> * @param header * @param articleRange * @return Returns a DotTerminatedMessageReader if successful, null * otherwise * @exception IOException */ private Reader __retrieveHeader(String header, String articleRange) throws IOException { if (!NNTPReply.isPositiveCompletion(xhdr(header, articleRange))) return null; return new DotTerminatedMessageReader(_reader_); } /** * Return an article header for a specified post. * <p> * @param header the header to retrieve * @param articleNumber the article to retrieve the header for * @return a DotTerminatedReader if successful, null otherwise * @throws IOException */ public Reader retrieveHeader(String header, int articleNumber) throws IOException { return __retrieveHeader(header, Integer.toString(articleNumber)); } /** * Return an article header for all articles between lowArticleNumber * and highArticleNumber, inclusively. * <p> * @param header * @param lowArticleNumber * @param highArticleNumber * @return a DotTerminatedReader if successful, null otherwise * @throws IOException */ public Reader retrieveHeader(String header, int lowArticleNumber, int highArticleNumber) throws IOException { return __retrieveHeader(header, new String(lowArticleNumber + "-" + highArticleNumber)); } } /* Emacs configuration * Local variables: ** * mode: java ** * c-basic-offset: 4 ** * indent-tabs-mode: nil ** * End: ** */