simple accumulator

public class AccumulatingProfiler {
	public class AccumulatingProfileStep implements Comparable<AccumulatingProfileStep>, Serializable {
		private static final long serialVersionUID = 1L;
		public String name;
		public Long lastStartTime;
		public Long accumulatedTime;
		
		public AccumulatingProfileStep(String name) {
			this.name = name;
			this.lastStartTime = 0L;
			this.accumulatedTime = 0L;
		}
		
		public int compareTo(AccumulatingProfileStep o) {
			return this.accumulatedTime.compareTo(o.accumulatedTime);
		}
		
		public String toString() {
			return name + ": " + accumulatedTime/(1000*1000) + "ms";
		}
	}
	
	private Map<String, AccumulatingProfileStep> steps = new HashMap<>();
	
	public void start(String stepName) {
		AccumulatingProfileStep ps = this.steps.get(stepName);
		if (ps == null) {
			ps = new AccumulatingProfileStep(stepName);
			this.steps.put(stepName, ps);
		}
		ps.lastStartTime = System.nanoTime();
	}

	public void end(String stepName) {
		AccumulatingProfileStep ps = this.steps.get(stepName);
		if (ps == null) {
			return;
		}
		ps.accumulatedTime += System.nanoTime() - ps.lastStartTime;
		ps.lastStartTime = 0L;
	}
	

	public Map<String, AccumulatingProfileStep> getSteps() {
		return steps;
	}


	public void setSteps(Map<String, AccumulatingProfileStep> steps) {
		this.steps = steps;
	}
}