fix: Remove System.out.println statements (#16)

README.md

@@ -17,7 +17,7 @@ Java 1.7 and later.
 
 ### Add the Dependency
 
-The SDK is available via Maven Central and jCenter.
+The SDK is available via Maven Central.
 
 #### Gradle
 
@@ -223,6 +223,15 @@ Call<Void> singleResult = api.uploadEvents(batch);
 Response<Void> singleResponse = singleResult.execute();
 ```
 
+### Logging
+
+By default, logging is ignored.  Please implement your own LogHandler to handle log statements.
+
+```java
+Logger.setLogHandler(new DefaultLogHandler());
+Logger.info("Statement");
+```
+
 ### License
 
 [Apache License 2.0](http://www.apache.org/licenses/LICENSE-2.0)

build.gradle

@@ -7,12 +7,12 @@ apply from: '.scripts/maven.gradle'
 
 buildscript {
     repositories {
-        jcenter()
+        mavenCentral()
     }
 }
 
 repositories {
-    jcenter()
+    mavenCentral()
 }
 
 sourceCompatibility = JavaVersion.VERSION_1_7
@@ -47,6 +47,9 @@ ext {
     junit_version = "4.12"
     threetenbp_version = "1.3.5"
     json_fire_version = "1.8.0"
+    slf4j_core_version = "1.2.3"
+    slf4j_classic_version = "1.2.3"
+    slf4j_version = "1.7.30"
 }
 
 dependencies {
@@ -58,4 +61,7 @@ dependencies {
     compile "io.gsonfire:gson-fire:$json_fire_version"
     compile "org.threeten:threetenbp:$threetenbp_version"
     testCompile "junit:junit:$junit_version"
+    testCompile "ch.qos.logback:logback-core:$slf4j_core_version"
+    testCompile "ch.qos.logback:logback-classic:$slf4j_classic_version"
+    testCompile "org.slf4j:slf4j-api:$slf4j_version"
 }

src/main/java/com/mparticle/ApiClient.java

@@ -12,7 +12,6 @@
 import java.util.Map;
 
 import okhttp3.Interceptor;
-import okhttp3.MediaType;
 import okhttp3.OkHttpClient;
 import okhttp3.Protocol;
 import okhttp3.RequestBody;
@@ -145,9 +144,9 @@ static class RateLimitInterceptor implements Interceptor {
 
     @Override
     public Response intercept(Chain chain) throws IOException {
-      System.out.println("Starting request: " + chain.request().toString());
+      Logger.info("Starting request: " + chain.request().toString());
       if (retryAfter != null && System.currentTimeMillis() < retryAfter) {
-        System.out.println("This endpoint is currently rate-limited, please retry after" + retryAfter + "ms, returning a local 429 response");
+        Logger.info("This endpoint is currently rate-limited, please retry after" + retryAfter + "ms, returning a local 429 response");
         return new Response.Builder()
                 .request(chain.request())
                 .addHeader("RETRY_AFTER", retryAfter.toString())
@@ -159,8 +158,8 @@ public Response intercept(Chain chain) throws IOException {
       }
 
       Response response = chain.proceed(chain.request());
-      System.out.println("Response " + response.code());
-      System.out.println(response);
+      Logger.info("Response " + response.code());
+      Logger.info(String.valueOf(response));
       if (response.code() == 429) {
         //Most HttpUrlConnectionImpl's are case insensitive, but the interface
         //doesn't actually restrict it so let's be safe and check.
@@ -170,17 +169,17 @@ public Response intercept(Chain chain) throws IOException {
         }
         try {
           if (retryAfterString == null) {
-            System.out.println("No Retry-After value found");
+            Logger.info("No Retry-After value found");
           } else {
             long parsedThrottle = Long.parseLong(retryAfterString) * 1000;
             if (parsedThrottle > 0) {
               retryAfter = System.currentTimeMillis() + parsedThrottle;
-              System.out.println("Retry-After value: " + parsedThrottle);
-              System.out.println("Next request may not be attempted for " + retryAfter + "ms");
+              Logger.info("Retry-After value: " + parsedThrottle);
+              Logger.info("Next request may not be attempted for " + retryAfter + "ms");
             }
           }
         } catch (NumberFormatException nfe) {
-          System.out.println("Unable to parse retry-after header, next request will not be rate-limited.");
+          Logger.info("Unable to parse retry-after header, next request will not be rate-limited.");
         }
       }
       return response;

src/main/java/com/mparticle/Logger.java

@@ -0,0 +1,55 @@
+package com.mparticle;
+
+public class Logger {
+    private static AbstractLogHandler logHandler;
+    public enum LogLevel {
+        INFO, ERROR
+    }
+
+    public static void info(String message) {
+        if(getLogHandler() != null)
+            getLogHandler().log(LogLevel.INFO, null, message);
+    }
+
+    public static void error(String message) {
+        if(getLogHandler() != null)
+            getLogHandler().log(LogLevel.ERROR, null, message);
+    }
+
+    public static void error(Throwable error) {
+        if(getLogHandler() != null)
+            getLogHandler().log(LogLevel.ERROR, error, error.toString());
+    }
+
+    /**
+     * Testing method. Use this method to intercept Logs, or customize what happens when something is logged.
+     * For example, you can use this method to throw an exception every time an "error" log is called.
+     * @param logListener
+     */
+    public static void setLogHandler(AbstractLogHandler logListener) {
+        Logger.logHandler = logListener;
+    }
+
+    public static AbstractLogHandler getLogHandler() {
+        return logHandler;
+    }
+
+    public abstract static class AbstractLogHandler {
+
+        public void log(LogLevel priority, Throwable error, String message) {
+            if (message != null) {
+                switch (priority) {
+                    case ERROR:
+                        error(error, message);
+                        break;
+                    case INFO:
+                        info(message);
+                }
+            }
+        }
+
+        public abstract void info(String message);
+        public abstract void error(Throwable error, String message);
+    }
+}
+

src/test/java/com/mparticle/client/DefaultLogHandler.java

@@ -0,0 +1,24 @@
+package com.mparticle.client;
+
+import com.mparticle.Logger.AbstractLogHandler;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class DefaultLogHandler extends AbstractLogHandler {
+
+    private static final Logger Log = LoggerFactory.getLogger(DefaultLogHandler.class);
+    @Override
+    public void info(String message) {
+        Log.info(message);
+
+    }
+
+    @Override
+    public void error(Throwable error, String message) {
+        if (error != null) {
+            Log.error(error.toString());
+        } else {
+            Log.error(message);
+        }
+    }
+}

src/test/java/com/mparticle/client/EventsApiTest.java

@@ -2,6 +2,7 @@
 
 import com.google.gson.Gson;
 import com.mparticle.ApiClient;
+import com.mparticle.Logger;
 import com.mparticle.model.*;
 import org.junit.Assert;
 import org.junit.Before;
@@ -28,6 +29,18 @@ public void setup() {
                 .createService(EventsApi.class);
     }
 
+    @Test
+    public void logStringWtihLogger() {
+        Logger.setLogHandler(new DefaultLogHandler());
+        Logger.info("Test");
+        Assert.assertNotNull(Logger.getLogHandler());
+    }
+
+    @Test
+    public void logStringNoLogger() {
+        Logger.info("Test");
+        Assert.assertNull(Logger.getLogHandler());
+    }
 
     @Test
     public void uploadUserIdentitiesAndAttributes() throws Exception {