Miscellany

import java.net.InetAddress;
import java.io.InputStream;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.text.ParseException;
import java.util.StringTokenizer;
 
public final class NetworkInfo {
	private final static String getMacAddress() throws IOException {
		String os = System.getProperty("os.name");
 
		try {
			if(os.startsWith("Windows")) {
				return windowsParseMacAddress(windowsRunIpConfigCommand());
			} else if(os.startsWith("Linux")) {
				return linuxParseMacAddress(linuxRunIfConfigCommand());
			} else {
				throw new IOException("unknown operating system: " + os);
			}
		} catch(ParseException ex) {
			ex.printStackTrace();
			throw new IOException(ex.getMessage());
		}
	}
 
 
	/*
	 * Linux stuff
	 */
	private final static String linuxParseMacAddress(String ipConfigResponse) throws ParseException {
		String localHost = null;
		try {
			localHost = InetAddress.getLocalHost().getHostAddress();
		} catch(java.net.UnknownHostException ex) {
			ex.printStackTrace();
			throw new ParseException(ex.getMessage(), 0);
		}
 
		StringTokenizer tokenizer = new StringTokenizer(ipConfigResponse, "\n");
		String lastMacAddress = null;
 
		while(tokenizer.hasMoreTokens()) {
			String line = tokenizer.nextToken().trim();
			boolean containsLocalHost = line.indexOf(localHost) >= 0;
 
			// see if line contains IP address
			if(containsLocalHost && lastMacAddress != null) {
				return lastMacAddress;
			}
 
			// see if line contains MAC address
			int macAddressPosition = line.indexOf("HWaddr");
			if(macAddressPosition <= 0) continue;
 
			String macAddressCandidate = line.substring(macAddressPosition + 6).trim();
			if(linuxIsMacAddress(macAddressCandidate)) {
				lastMacAddress = macAddressCandidate;
				continue;
			}
		}
 
		ParseException ex = new ParseException
			("cannot read MAC address for " + localHost + " from [" + ipConfigResponse + "]", 0);
		ex.printStackTrace();
		throw ex;
	}
 
 
	private final static boolean linuxIsMacAddress(String macAddressCandidate) {
		// TODO: use a smart regular expression
		if(macAddressCandidate.length() != 17) return false;
		return true;
	}
 
 
	private final static String linuxRunIfConfigCommand() throws IOException {
		Process p = Runtime.getRuntime().exec("ifconfig");
		InputStream stdoutStream = new BufferedInputStream(p.getInputStream());
 
		StringBuffer buffer= new StringBuffer();
		for (;;) {
			int c = stdoutStream.read();
			if (c == -1) break;
			buffer.append((char)c);
		}
		String outputText = buffer.toString();
 
		stdoutStream.close();
 
		return outputText;
	}
 
 
 
	/*
	 * Windows stuff
	 */
	private final static String windowsParseMacAddress(String ipConfigResponse) throws ParseException {
		String localHost = null;
		try {
			localHost = InetAddress.getLocalHost().getHostAddress();
		} catch(java.net.UnknownHostException ex) {
			ex.printStackTrace();
			throw new ParseException(ex.getMessage(), 0);
		}
 
		StringTokenizer tokenizer = new StringTokenizer(ipConfigResponse, "\n");
		String lastMacAddress = null;
 
		while(tokenizer.hasMoreTokens()) {
			String line = tokenizer.nextToken().trim();
 
			// see if line contains IP address
			if(line.endsWith(localHost) && lastMacAddress != null) {
				return lastMacAddress;
			}
 
			// see if line contains MAC address
			int macAddressPosition = line.indexOf(":");
			if(macAddressPosition <= 0) continue;
 
			String macAddressCandidate = line.substring(macAddressPosition + 1).trim();
			if(windowsIsMacAddress(macAddressCandidate)) {
				lastMacAddress = macAddressCandidate;
				continue;
			}
		}
 
		ParseException ex = new ParseException("cannot read MAC address from [" + ipConfigResponse + "]", 0);
		ex.printStackTrace();
		throw ex;
	}
 
 
	private final static boolean windowsIsMacAddress(String macAddressCandidate) {
		// TODO: use a smart regular expression
		if(macAddressCandidate.length() != 17) return false;
 
		return true;
	}
 
 
	private final static String windowsRunIpConfigCommand() throws IOException {
		Process p = Runtime.getRuntime().exec("ipconfig /all");
		InputStream stdoutStream = new BufferedInputStream(p.getInputStream());
 
		StringBuffer buffer= new StringBuffer();
		for (;;) {
			int c = stdoutStream.read();
			if (c == -1) break;
			buffer.append((char)c);
		}
		String outputText = buffer.toString();
 
		stdoutStream.close();
 
		return outputText;
	}
 
 
 
	/*
	 * Main
	 */
	public final static void main(String[] args) {
		try {
			System.out.println("Network infos");
 
			System.out.println("  Operating System: " + System.getProperty("os.name"));
			System.out.println("  IP/Localhost: " + InetAddress.getLocalHost().getHostAddress());
			System.out.println("  MAC Address: " + getMacAddress());
		} catch(Throwable t) {
			t.printStackTrace();
		}
	}
}