import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.util.zip.CRC32;
import java.util.zip.Checksum;
/**
* Uses CRC32 algorithm for creating fingerprint.
*
* @author Alex Objelean
*/
public class CRC32HashBuilder {
/**
* {@inheritDoc}
*/
public String getHash(final InputStream input) throws IOException {
if (input == null) {
throw new IllegalArgumentException("Content cannot be null!");
}
final Checksum checksum = new CRC32();
final byte[] bytes = new byte[1024];
int len = 0;
while ((len = input.read(bytes)) >= 0) {
checksum.update(bytes, 0, len);
}
final String hash = new BigInteger(Long.toString(checksum.getValue()))
.toString(16);
return hash;
}
}