SlidingWindowMap - File One

package com.malagasys.slidingwindow;

import java.util.ArrayDeque;
import java.util.Deque;

class SlidingWindow {
    /**
     * Keep track of all of the timestamp of the call.
     */
    private final Deque<Long> callsTimestamp = new ArrayDeque<>();

    /** Width of the window in millisecond. */
    private final long width;

    /** The maximum number of call within the window. */
    private final int maxCount;

    /** Current time of the window */
    private long currentTime;

    SlidingWindow(long width, int maxCall) {
        this.width = width;
        this.maxCount = maxCall;
    }

    /**
     * Log a call occuring at the given timestamp.
     * @param timestamp
     */
    public void logcall(long timestamp) {
        if (callsTimestamp.size() >= maxCount) {
            throw new IllegalStateException("Maximum number of call reached.");
        }
        callsTimestamp.add(timestamp);
    }

    public boolean isFull() {
        return callsTimestamp.size() == maxCount;
    }

    /**
     * Slide the window so that the end of the window matches the given timestamp.
     */
    public void slideTo(long currentTimestamp) {
        currentTime = currentTimestamp;
        long windowLeft = currentTime - width;

        //Strip methodcalls that fall out of the window from the head of the queue.
        boolean stop = false;
        do {
            Long first = callsTimestamp.peekFirst();
            if (first == null || first >= windowLeft) {
                stop = true;
            } else {
                if (first != null) {
                    //this call falls out the window ==> remove it.
                    callsTimestamp.removeFirst();
                }
            }
        } while (!stop);
    }
}