Added setSchema

- The right way. Should be done similarly in snowplow/snowplow-ios-tracker#47

Author: jonalmeida

src/main/java/com/snowplowanalytics/snowplow/tracker/Constants.java

@@ -14,9 +14,11 @@
 package com.snowplowanalytics.snowplow.tracker;
 
 public class Constants {
-    public static final String DEFAULT_PLATFORM = "pc";
-    public static final String DEFAULT_VENDOR = "com.snowplowanalytics.snowplow";
+    public static final String DEFAULT_VENDOR = "iglu:com.snowplowanalytics.snowplow";
+    public static final String DEFAULT_SCHEMA_TAG = "jsonschema";
+    public static final String DEFAULT_SCHEMA_VERSION = "1-0-0";
     public static final String SCHEMA_PAYLOAD_DATA = "iglu:com.snowplowanalytics.snowplow/payload_data/jsonschema/1-0-0";
 
     public static final String EVENT_PAGE_VIEW = "pv";
+
 }

src/main/java/com/snowplowanalytics/snowplow/tracker/Tracker.java

@@ -21,12 +21,16 @@ public class Tracker {
     private Emitter emitter;
     private String appId;
     private String namespace;
+    private String contextSchema;
+    private String unstructSchema;
 
     public Tracker(Emitter emitter, String appId, boolean base64Encoded, String namespace) {
         this.emitter = emitter;
         this.appId = appId;
         this.base64Encoded = base64Encoded;
         this.namespace = namespace;
+        this.setSchema(Constants.DEFAULT_VENDOR, Constants.DEFAULT_SCHEMA_TAG,
+                Constants.DEFAULT_SCHEMA_VERSION);
     }
 
     private Payload completePayload(Payload payload, Map context, double timestamp) {
@@ -48,6 +52,11 @@ private void addTrackerPayload(Payload payload) {
         this.emitter.addToBuffer(payload);
     }
 
+    public void setSchema(String vendor, String schemaTag, String version) {
+        this.contextSchema = vendor + "/contexts/" + schemaTag + version;
+        this.unstructSchema = vendor + "/unstruct_event/" + schemaTag + version;
+    }
+
     public void trackPageView(String pageUrl, String pageTitle, String referrer, Map context) {
         trackPageView(pageUrl,pageTitle, referrer,context, 0);
     }