possibility to use other connection managers (besides HttpClient)

src/main/java/com/ecwid/mailchimp/MailChimpAPIConnection.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2012 Ecwid, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.ecwid.mailchimp;
+
+import java.io.Closeable;
+import java.io.IOException;
+
+/**
+ * Abstract connection manager to access MailChimp API service point.
+ * 
+ * @author Vasily Karyaev <[email protected]>
+ */
+public interface MailChimpAPIConnection extends Closeable {
+
+	/**
+	 * Make a POST request to MailChimp API service point.
+	 * 
+	 * @param url URL to post data to
+	 * @param payload data to post
+	 * 
+	 * @return service endpoint response body if the response was successful (a 2xx status code)
+	 * 
+	 * @throws IOException if an I/O error occurred during the communication,
+	 * or if the service point response was unsuccessful (>= 300 status code)
+	 */
+	public String post(String url, String payload) throws IOException;
+
+	/**
+	 * Release resources associated with the connection.
+	 */
+	@Override
+	public void close();
+}

src/main/java/com/ecwid/mailchimp/MailChimpClient.java

@@ -19,6 +19,7 @@
 import com.google.gson.Gson;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonParser;
+import java.io.Closeable;
 import java.io.IOException;
 import java.io.UnsupportedEncodingException;
 import java.net.URLEncoder;
@@ -35,18 +36,48 @@
  * 
  * @author Vasily Karyaev <[email protected]>
  */
-public class MailChimpClient {
+public class MailChimpClient implements Closeable {
 	private static final Logger log = Logger.getLogger(MailChimpClient.class.getName());
 
-	private final HttpClient http = new DefaultHttpClient();
+	private final MailChimpAPIConnection connection;
+
+	/**
+	 * Construct a {@code MailChimpClient} object accessing MailChimp API service point
+	 * through the specified connection manager.
+	 * 
+	 * @param connection connection manager to be used to access the service point
+	 */
+	public MailChimpClient(MailChimpAPIConnection connection) {
+		this.connection = connection;
+	}
+
+	/**
+	 * Construct a {@code MailChimpClient} object accessing MailChimp API service point
+	 * through the default connection manager (based on Apache HttpClient library).
+	 */
+	public MailChimpClient() {
+		this(new MailChimpAPIConnection() {
+			final HttpClient http = new DefaultHttpClient();
+
+			@Override
+			public String post(String url, String payload) throws IOException {
+				HttpPost post = new HttpPost(url);
+				post.setEntity(new StringEntity(URLEncoder.encode(payload, "UTF-8")));
+				return http.execute(post, new BasicResponseHandler());
+			}
+
+			@Override
+			public void close() {
+				http.getConnectionManager().shutdown();
+			}
+		});
+	}
 
 	private String execute(String url, String request) throws IOException {
 		if(log.isLoggable(Level.FINE)) {
 			log.fine("Post to "+url+" : "+request);
 		}
-		HttpPost post = new HttpPost(url);
-		post.setEntity(new StringEntity(URLEncoder.encode(request, "UTF-8")));
-		String response = http.execute(post, new BasicResponseHandler());
+		String response = connection.post(url, request);
 		if(log.isLoggable(Level.FINE)) {
 			log.fine("Response: "+response);
 		}
@@ -99,9 +130,10 @@ private String buildUrl(MailChimpMethod<?> method) throws UnsupportedEncodingExc
 	}
 
 	/**
-	 * Release resources.
+	 * Release resources associated with the connection to MailChimp API service point.
 	 */
+	@Override
 	public void close() {
-		http.getConnectionManager().shutdown();
+		connection.close();
 	}
 }