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Spamcheck.java
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Spamcheck.java
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// 4. Write a simple program to illustrate spam check.
import java.net.*;
public class Spamcheck {
public static final String BLACKHOLE = "sbl.spamhaus.org";
public static void main(String[] args) throws UnknownHostException {
for (String arg : args) {
if (isSpammer(arg)) {
System.out.println(arg + " is a known spammer.");
} else {
System.out.println(arg + " appears legitimate.");
}
}
}
private static boolean isSpammer(String arg) {
try {
InetAddress address = InetAddress.getByName(arg);
byte[] quad = address.getAddress();
// Reverse the octet order to form the correct query
String query = BLACKHOLE;
for (int i = quad.length - 1; i >= 0; i--) {
int unsignedByte = quad[i] < 0 ? quad[i] + 256 : quad[i];
query = unsignedByte + "." + query;
}
InetAddress.getByName(query);
return true; // If no exception, the IP is listed
} catch (UnknownHostException e) {
return false; // Not listed in the blacklist
}
}
}