MY_COMPILER/frontend/lexer/TokenStream.java

package frontend.lexer;

import java.util.ArrayList;

public class TokenStream {
    private ArrayList<Token> tokens;
    private int currentIndex;

    public TokenStream(ArrayList<Token> tokens) {
        this.tokens = tokens;
    }

    public Token read() {
        if (currentIndex < tokens.size()) {
            return tokens.get(currentIndex++);
        } else {
            return null;
        }
    }

    public void recall() {
        if (currentIndex > 0) {
            currentIndex--;
        }
    }

    public int getCurrentIndex() {
        return currentIndex;
    }

    public void resetIndex(int index) {
        currentIndex = index;
    }

    public Token peek(int step) {
        if (currentIndex + step < tokens.size()) {
            return tokens.get(currentIndex + step);
        } else {
            return null;
        }
    }
}