Java tutorial
/** * Licensed to JumpMind Inc under one or more contributor * license agreements. See the NOTICE file distributed * with this work for additional information regarding * copyright ownership. JumpMind Inc licenses this file * to you under the GNU General Public License, version 3.0 (GPLv3) * (the "License"); you may not use this file except in compliance * with the License. * * You should have received a copy of the GNU General Public License, * version 3.0 (GPLv3) along with this library; if not, see * <http://www.gnu.org/licenses/>. * * 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.jumpmind.util; import static org.apache.commons.lang.StringUtils.isBlank; import static org.apache.commons.lang.StringUtils.isNotBlank; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.net.DatagramSocket; import java.net.InetAddress; import java.net.NetworkInterface; import java.net.ServerSocket; import java.net.UnknownHostException; import java.util.Date; import java.util.Enumeration; import java.util.TimeZone; import java.util.zip.ZipEntry; import java.util.zip.ZipInputStream; import org.apache.commons.io.IOUtils; import org.apache.commons.lang.time.FastDateFormat; import org.jumpmind.exception.IoException; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * General application utility methods */ public class AppUtils { public final static String SYSPROP_HOST_NAME = "host.name"; public final static String SYSPROP_PORT_NUMBER = "port.number"; public final static String SYSPROP_IP_ADDRESS = "ip.address"; private static String UNKNOWN = "unknown"; private static Logger log = LoggerFactory.getLogger(AppUtils.class); private static FastDateFormat timezoneFormatter = FastDateFormat.getInstance("Z"); public static String getSymHome() { String home = System.getenv("SYM_HOME"); if (home == null) { home = "."; } return home; } public static String getCanonicalSymHome(String dirName) { if (!dirName.startsWith("/") && !dirName.startsWith("\\")) { dirName = getSymHome() + "/" + dirName; } return dirName; } public static String getHostName() { String hostName = System.getProperty(SYSPROP_HOST_NAME, UNKNOWN); if (UNKNOWN.equals(hostName)) { try { hostName = System.getenv("HOSTNAME"); if (isBlank(hostName)) { hostName = System.getenv("COMPUTERNAME"); } if (isBlank(hostName)) { try { hostName = IOUtils.toString(Runtime.getRuntime().exec("hostname").getInputStream()); } catch (Exception ex) { } } if (isBlank(hostName)) { hostName = InetAddress.getByName(InetAddress.getLocalHost().getHostAddress()).getHostName(); } if (isNotBlank(hostName)) { hostName = hostName.trim(); } } catch (Exception ex) { log.warn("", ex); } } return hostName; } public static String getPortNumber() { String portNumber = System.getProperty(SYSPROP_PORT_NUMBER, System.getProperty("http.port", System.getProperty("https.port", UNKNOWN))); if (UNKNOWN.equals(portNumber)) { try { portNumber = "31415"; } catch (Exception ex) { log.warn("", ex); } } return portNumber; } public static String getIpAddress() { String ipAddress = System.getProperty(SYSPROP_IP_ADDRESS, UNKNOWN); if (UNKNOWN.equals(ipAddress)) { try { Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces(); while (interfaces.hasMoreElements()) { NetworkInterface networkInterface = interfaces.nextElement(); Enumeration<InetAddress> inetAddresses = networkInterface.getInetAddresses(); while (inetAddresses.hasMoreElements()) { InetAddress inetAddress = inetAddresses.nextElement(); if (!inetAddress.isLoopbackAddress()) { ipAddress = inetAddress.getHostAddress(); } } } } catch (Exception ex) { log.warn("", ex); } finally { } } if (UNKNOWN.equals(ipAddress)) { try { ipAddress = InetAddress.getLocalHost().getHostAddress(); } catch (UnknownHostException ex) { log.warn("", ex); ipAddress = "127.0.0.1"; } } return ipAddress; } /** * This method will return the timezone in RFC822 format. </p> The format * ("-+HH:MM") has advantages over the older timezone codes ("AAA"). The * difference of 5 hours from GMT is obvious with "-05:00" but only implied * with "EST". There is no ambiguity saying "-06:00", but you don't know if * "CST" means Central Standard Time ("-06:00") or China Standard Time * ("+08:00"). The timezone codes need to be loaded on the system, and * definitions are not standardized between systems. Therefore, to remain * agnostic to operating systems and databases, the RFC822 format is the * best choice. */ public static String getTimezoneOffset() { String tz = timezoneFormatter.format(new Date()); if (tz != null && tz.length() == 5) { return tz.substring(0, 3) + ":" + tz.substring(3, 5); } return null; } /** * @param timezoneOffset * see description for {@link #getTimezoneOffset()} * @return a date object that represents the local date and time at the * passed in offset */ public static Date getLocalDateForOffset(String timezoneOffset) { long currentTime = System.currentTimeMillis(); int myOffset = TimeZone.getDefault().getOffset(currentTime); int theirOffset = TimeZone.getTimeZone("GMT" + timezoneOffset).getOffset(currentTime); return new Date(currentTime - myOffset + theirOffset); } /** * Useful method to sleep that catches and ignores the * {@link InterruptedException} * * @param ms * milliseconds to sleep */ public static void sleep(long ms) { if (ms > 0) { try { Thread.sleep(ms); } catch (InterruptedException e) { log.info("Interrupted while sleeping for " + ms); } } } public static boolean isSystemPropertySet(String propName, boolean defaultValue) { return "true".equalsIgnoreCase(System.getProperty(propName, Boolean.toString(defaultValue))); } /** * Checks to see if a specific port is available. * * @param port * the port to check for availability */ public static boolean isPortAvailable(int port) { if (port < 1 || port > 65535) { throw new IllegalArgumentException("Invalid start port: " + port); } ServerSocket ss = null; DatagramSocket ds = null; try { ss = new ServerSocket(port); ss.setReuseAddress(true); ds = new DatagramSocket(port); ds.setReuseAddress(true); return true; } catch (IOException e) { } finally { if (ds != null) { ds.close(); } if (ss != null) { try { ss.close(); } catch (IOException e) { /* should not be thrown */ } } } return false; } public static void unzip(InputStream in, File toDir) { try { ZipInputStream is = new ZipInputStream(in); ZipEntry entry = null; do { entry = is.getNextEntry(); if (entry != null) { if (entry.isDirectory()) { File dir = new File(toDir, entry.getName()); dir.mkdirs(); dir.setLastModified(entry.getTime()); } else { File file = new File(toDir, entry.getName()); if (!file.getParentFile().exists()) { file.getParentFile().mkdirs(); file.getParentFile().setLastModified(entry.getTime()); } FileOutputStream fos = new FileOutputStream(file); try { IOUtils.copy(is, fos); file.setLastModified(entry.getTime()); } finally { IOUtils.closeQuietly(fos); } } } } while (entry != null); } catch (IOException e) { throw new IoException(e); } } }