Add block worker report and worker report.

servers/src/main/java/tachyon/worker/BlockWorkerReport.java

@@ -0,0 +1,39 @@
+package tachyon.worker;
+
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Represents the data the CoreWorker will send to the master in its periodic heartbeat.
+ */
+// TODO: Make this a thrift object?
+public class BlockWorkerReport extends WorkerReport {
+  private final long mWorkerId;
+  private final List<Long> mUsedBytesOnTiers;
+  private final List<Long> mRemovedBlocks;
+  private final Map<Long, List<Long>> mAddedBlocks;
+
+  public BlockWorkerReport(long workerId, List<Long> usedBytesOnTiers, List<Long> removedBlocks,
+      Map<Long, List<Long>> addedBlocks) {
+    mWorkerId = workerId;
+    mUsedBytesOnTiers = usedBytesOnTiers;
+    mRemovedBlocks = removedBlocks;
+    mAddedBlocks = addedBlocks;
+  }
+
+  public Map<Long, List<Long>> getAddedBlocks() {
+    return mAddedBlocks;
+  }
+
+  public List<Long> getRemovedBlocks() {
+    return mRemovedBlocks;
+  }
+
+  public List<Long> getUsedBytesOnTiers() {
+    return mUsedBytesOnTiers;
+  }
+
+  public long getWorkerId() {
+    return mWorkerId;
+  }
+}

servers/src/main/java/tachyon/worker/TachyonWorker.java

@@ -80,8 +80,8 @@ public void run() {
         }
 
         try {
-          BlockReport blockReport = mCoreWorker.getBlockReport();
-          cmd = mMasterClient.worker_heartbeat(mWorkerId, blockReport.getUsedBytes(),
+          BlockWorkerReport blockReport = mCoreWorker.getReport();
+          cmd = mMasterClient.worker_heartbeat(mWorkerId, blockReport.getUsedBytesOnTiers(),
               blockReport.getRemovedBlocks(), blockReport.getAddedBlocks());
           lastHeartbeatMs = System.currentTimeMillis();
         } catch (IOException e) {

servers/src/main/java/tachyon/worker/WorkerReport.java

@@ -0,0 +1,8 @@
+package tachyon.worker;
+
+/**
+ * Represents a report from the worker to the master. Each worker type should implement its own
+ * version of the report.
+ */
+public class WorkerReport {
+}