How to make a deep copy of lucene TokenStream object - solr

Question

I am trying to create a custom solr filter which will keep only the token that has maximum integer value. In doing so, I have written the following code so far:
public final class MaxValueTokenFilter extends TokenFilter {
private final CharTermAttribute termAttribute = addAttribute(CharTermAttribute.class);
public MaxValueTokenFilter(TokenStream in) {
super(in);
}
#Override
public boolean incrementToken() throws IOException {
TokenStream clonedTokenStream = DeepCopy???(input);
int maxVal = 0;
//increamenting the clonedTokenStream should not increment the actual tokenStream
while (clonedToken.incrementToken()) {
final String term = termAttribute.toString();
int currentNumber = Integer.parseInt(term);
if(currentNumber > maxVal)
{
maxVal = currentNumber;
}
}
//increment the actual token to match the maximum value
while (input.incrementToken()) {
final String term = termAttribute.toString();
int currentNumber = Integer.parseInt(term);
if(currentNumber == maxVal)
{
return true;
}
}
return false;
}
#Override
public void reset() throws IOException {
super.reset();
}
}
Can somebody help me to make the DeepCopy of the TokenStream object so that incrementing the copied TokenStream does not increment the actual TokenStream.