NewGroupsOrNewsQuery.java
/*
* 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.Calendar;
import java.util.Objects;
/**
* The NewGroupsOrNewsQuery class. This is used to issue NNTP NEWGROUPS and NEWNEWS queries, implemented by
* {@link org.apache.commons.net.nntp.NNTPClient#listNewNewsgroups listNewNewsGroups } and {@link org.apache.commons.net.nntp.NNTPClient#listNewNews listNewNews
* } respectively. It prevents you from having to format date, time, distribution, and newgroup arguments.
* <p>
* You might use the class as follows:
* </p>
*
* <pre>
* query = new NewsGroupsOrNewsQuery(new GregorianCalendar(97, 11, 15), false);
* query.addDistribution("comp");
* NewsgroupInfo[] newsgroups = client.listNewgroups(query);
* </pre>
*
* This will retrieve the list of newsgroups starting with the comp. distribution prefix created since midnight 11/15/97.
*
* @see NNTPClient
*/
public final class NewGroupsOrNewsQuery {
private final String date, time;
private StringBuffer distributions;
private StringBuffer newsgroups;
private final boolean isGMT;
/**
* Creates a new query using the given time as a reference point.
*
* @param date The date since which new groups or news have arrived.
* @param gmt True if the date should be considered as GMT, false if not.
*/
public NewGroupsOrNewsQuery(final Calendar date, final boolean gmt) {
int num;
String str;
final StringBuilder buffer;
this.distributions = null;
this.newsgroups = null;
this.isGMT = gmt;
buffer = new StringBuilder();
// Get year
num = date.get(Calendar.YEAR);
str = Integer.toString(num);
num = str.length();
if (num >= 2) {
buffer.append(str.substring(num - 2));
} else {
buffer.append("00");
}
// Get month
num = date.get(Calendar.MONTH) + 1;
str = Integer.toString(num);
num = str.length();
if (num == 1) {
buffer.append('0');
buffer.append(str);
} else if (num == 2) {
buffer.append(str);
} else {
buffer.append("01");
}
// Get day
num = date.get(Calendar.DAY_OF_MONTH);
str = Integer.toString(num);
num = str.length();
if (num == 1) {
buffer.append('0');
buffer.append(str);
} else if (num == 2) {
buffer.append(str);
} else {
buffer.append("01");
}
this.date = buffer.toString();
buffer.setLength(0);
// Get hour
num = date.get(Calendar.HOUR_OF_DAY);
str = Integer.toString(num);
num = str.length();
if (num == 1) {
buffer.append('0');
buffer.append(str);
} else if (num == 2) {
buffer.append(str);
} else {
buffer.append("00");
}
// Get minutes
num = date.get(Calendar.MINUTE);
str = Integer.toString(num);
num = str.length();
if (num == 1) {
buffer.append('0');
buffer.append(str);
} else if (num == 2) {
buffer.append(str);
} else {
buffer.append("00");
}
// Get seconds
num = date.get(Calendar.SECOND);
str = Integer.toString(num);
num = str.length();
if (num == 1) {
buffer.append('0');
buffer.append(str);
} else if (num == 2) {
buffer.append(str);
} else {
buffer.append("00");
}
this.time = buffer.toString();
}
/**
* Add a distribution group to the query. The distribution part of a newsgroup is the segment of the name preceding the first dot (e.g., comp, alt, rec).
* Only those newsgroups matching one of the distributions or, in the case of NEWNEWS, an article in a newsgroup matching one of the distributions, will be
* reported as a query result. Adding distributions is purely optional.
*
* @param distribution A distribution to add to the query.
*/
public void addDistribution(final String distribution) {
if (distributions != null) {
distributions.append(',');
} else {
distributions = new StringBuffer();
}
distributions.append(distribution);
}
/**
* Add a newsgroup to the list of newsgroups being queried. Newsgroups added this way are only meaningful to the NEWNEWS command. Newsgroup names may
* include the <code> * </code> wildcard, as in <code>comp.lang.* </code> or <code> comp.lang.java.* </code>. Adding at least one newsgroup is mandatory for
* the NEWNEWS command.
*
* @param newsgroup The newsgroup to add to the list of groups to be checked for new news.
*/
public void addNewsgroup(final String newsgroup) {
if (newsgroups != null) {
newsgroups.append(',');
} else {
newsgroups = new StringBuffer();
}
newsgroups.append(newsgroup);
}
/**
* Return the NNTP query formatted date (year, month, day in the form YYMMDD).
*
* @return The NNTP query formatted date.
*/
public String getDate() {
return date;
}
/**
* Return the comma separated list of distributions. This may be null if there are no distributions.
*
* @return The list of distributions, which may be null if no distributions have been specified.
*/
public String getDistributions() {
return Objects.toString(distributions, null);
}
/**
* Return the comma separated list of newsgroups. This may be null if there are no newsgroups
*
* @return The list of newsgroups, which may be null if no newsgroups have been specified.
*/
public String getNewsgroups() {
return Objects.toString(newsgroups, null);
}
/**
* Return the NNTP query formatted time (hour, minutes, seconds in the form HHMMSS).
*
* @return The NNTP query formatted time.
*/
public String getTime() {
return time;
}
/**
* Return whether or not the query date should be treated as GMT.
*
* @return True if the query date is to be treated as GMT, false if not.
*/
public boolean isGMT() {
return isGMT;
}
/**
* Add a newsgroup to the list of newsgroups being queried, but indicate that group should not be checked for new news. Newsgroups added this way are only
* meaningful to the NEWNEWS command. Newsgroup names may include the <code> * </code> wildcard, as in <code>comp.lang.* </code> or
* <code> comp.lang.java.* </code>.
* <p>
* The following would create a query that searched for new news in all comp.lang.java newsgroups except for comp.lang.java.advocacy.
* </p>
*
* <pre>
* query.addNewsgroup("comp.lang.java.*");
* query.omitNewsgroup("comp.lang.java.advocacy");
* </pre>
*
* @param newsgroup The newsgroup to add to the list of groups to be checked for new news, but which should be omitted from the search for new news.
*/
public void omitNewsgroup(final String newsgroup) {
addNewsgroup("!" + newsgroup);
}
}