1 files changed, 51 insertions, 0 deletions
diff --git a/src/main/java/com/att/research/mdbc/tables/StagingTable.java b/src/main/java/com/att/research/mdbc/tables/StagingTable.java
new file mode 100644
index 0000000..c16f11c
--- /dev/null
+++ b/src/main/java/com/att/research/mdbc/tables/StagingTable.java
@@ -0,0 +1,51 @@
+package com.att.research.mdbc.tables;
+
+import java.io.Serializable;
+import java.util.Deque;
+import java.util.HashMap;
+import java.util.LinkedList;
+import java.util.Set;
+import org.apache.commons.lang3.tuple.Pair;
+import org.json.JSONObject;
+
+import com.att.research.logging.EELFLoggerDelegate;
+
+public class StagingTable implements Serializable{
+	/**
+	 * 
+	 */
+	private static final long serialVersionUID = 7583182634761771943L;
+	private transient static EELFLoggerDelegate logger = EELFLoggerDelegate.getLogger(StagingTable.class);
+	//primary key -> Operation
+	private HashMap<String,Deque<Operation>> operations;
+	
+	public StagingTable() {
+		operations = new HashMap<>();
+	}
+	
+	synchronized public void addOperation(String key, OperationType type, String oldVal, String newVal) {
+		if(!operations.containsKey(key)) {
+			operations.put(key, new LinkedList<>());
+		}
+		operations.get(key).add(new Operation(type,newVal,oldVal));
+	}
+	
+	synchronized public Deque<Pair<String,Operation>> getIterableSnapshot() throws NoSuchFieldException{
+		Deque<Pair<String,Operation>> response=new LinkedList<Pair<String,Operation>>();
+		//\TODO: check if we can just return the last change to a given key 
+		Set<String> keys = operations.keySet();
+		for(String key : keys) {
+			Deque<Operation> ops = operations.get(key);
+			if(ops.isEmpty()) {
+				logger.error(EELFLoggerDelegate.errorLogger, "Invalid state of the Operation data structure when creating snapshot");
+				throw new NoSuchFieldException("Invalid state of the operation data structure");
+			}
+			response.add(Pair.of(key,ops.getLast()));
+		}
+		return response;
+	}
+	
+	synchronized public void clean() {
+		operations.clear();
+	}
+}