for Hao

gistfile1.java

package com.example.test;

import java.io.Closeable;
import java.io.IOException;

public abstract class Parser<Input, Reader, Result> {
  public Result parse(Input input) throws IOException {
		if (null == input) {
			return null;
		}

		Result result = doParse(input, makeReader(input));

		if (input instanceof Closeable) {
			((Closeable) input).close();
		}

		return result;
	}

	protected abstract Reader makeReader(Input input);

	protected abstract Result doParse(Input input, Reader reader);
}