Wrapping HTTPURLConnection

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Map;
import java.util.Map.Entry;

import com.google.appengine.repackaged.com.google.common.base.StringUtil;

public class URLFetch {
	private String url;
	private String method;
	private String cookie;
	private String response;
	private Integer responseCode;
	private boolean isConnected = false;
	
	public URLFetch(String url, String method){
		this.url = url;
		this.method = method;
	}
	
	public String getCookie() throws IOException{
		if(!isConnected){
			throw new IOException("まだ接続していません");
		}
		return this.cookie;
	}
	public String getResponse() throws IOException{
		if(!isConnected){
			throw new IOException("まだ接続していません");
		}
		return this.response;
	}
	public Integer getResponseCode() throws IOException{
		if(!isConnected){
			throw new IOException("まだ接続していません");
		}
		return this.responseCode;
	}
	
	public void newConnection(String url, String method){
		this.url = url;
		this.method = method;
		this.cookie = null;
		this.response = null;
		this.responseCode = null;
		this.isConnected = false;
	}

	public void doConnect(Map<String, String> params, String cookie) throws IOException{
		URL url = new URL(this.url);
		HttpURLConnection con = (HttpURLConnection) url.openConnection();
		con.setRequestMethod(this.method);
		if(method.toLowerCase().equals("get")){
			con.setDoInput(true);
			if(cookie != null){
				con.setInstanceFollowRedirects(false);
				con.setRequestProperty("Cookie", cookie);
			}
			con.connect();
		}else if(method.toLowerCase().equals("post")){
			if(params != null){
				con.setRequestProperty("Content-type", "application/x-www-form-urlencoded");
			}
			if(cookie != null){
				con.setInstanceFollowRedirects(false);
				con.setRequestProperty("Cookie", cookie);
			}
			con.setDoInput(true);
			con.setDoOutput(true);
			
			con.connect();
			if(params != null){
				OutputStreamWriter osw = new OutputStreamWriter(con.getOutputStream());
				osw.write(makeParams(params));
				osw.flush();
				osw.close();
			}
		}
		this.cookie = con.getHeaderField("Set-Cookie");
		this.responseCode = con.getResponseCode();
	    BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream(), "UTF-8"));
	    String result = "";
	    String line;
	    while ((line = in.readLine()) != null) {
	        result += line;
	    }
	    this.response = result;
	    this.isConnected = true;
	    con.disconnect();
	}
	
	private String makeParams(Map<String, String> params){
		if(params.isEmpty())
			return null;
		String result = "";
		for(Entry<String, String> e: params.entrySet()){
			result += e.getKey()+"="+e.getValue()+"&";
		}
		result = StringUtil.stripSuffix(result, "&");
		return result;
	}
}